Merge pull request #6939 from open-craft/content_libraries/previews

Add show/hide previews button to Content Libraries

cms/djangoapps/contentstore/views/component.py

@@ -16,6 +16,7 @@ from xmodule.modulestore.django import modulestore
 from xblock.core import XBlock
 from xblock.django.request import webob_to_django_response, django_to_webob_request
 from xblock.exceptions import NoSuchHandlerError
+from xblock.fields import Scope
 from xblock.plugin import PluginMissingError
 from xblock.runtime import Mixologist
 

cms/djangoapps/contentstore/views/item.py

@@ -264,7 +264,7 @@ def xblock_view_handler(request, usage_key_string, view_name):
                 # pylint: disable=too-many-format-args
                 return HttpResponse(
                     content="Couldn't parse paging parameters: enable_paging: "
-                            "%s, page_number: %s, page_size: %s".format(
+                            "{0}, page_number: {1}, page_size: {2}".format(
                                 request.REQUEST.get('enable_paging', 'false'),
                                 request.REQUEST.get('page_number', 0),
                                 request.REQUEST.get('page_size', 0)
@@ -273,6 +273,8 @@ def xblock_view_handler(request, usage_key_string, view_name):
                     content_type="text/plain",
                 )
 
+            force_render = request.REQUEST.get('force_render', None)
+
             # Set up the context to be passed to each XBlock's render method.
             context = {
                 'is_pages_view': is_pages_view,     # This setting disables the recursive wrapping of xblocks
@@ -281,6 +283,7 @@ def xblock_view_handler(request, usage_key_string, view_name):
                 'root_xblock': xblock if (view_name == 'container_preview') else None,
                 'reorderable_items': reorderable_items,
                 'paging': paging,
+                'force_render': force_render,
             }
 
             fragment = get_preview_fragment(request, xblock, context)

cms/djangoapps/contentstore/views/library.py

@@ -231,4 +231,5 @@ def manage_library_users(request, library_key_string):
         'allow_actions': bool(user_perms & STUDIO_EDIT_ROLES),
         'library_key': unicode(library_key),
         'lib_users_url': reverse_library_url('manage_library_users', library_key_string),
+        'show_children_previews': library.show_children_previews
     })

cms/djangoapps/contentstore/views/preview.py

@@ -113,6 +113,12 @@ class PreviewModuleSystem(ModuleSystem):  # pylint: disable=abstract-method
             if aside_type != 'acid_aside'
         ]
 
+    def render_child_placeholder(self, block, view_name, context):
+        """
+        Renders a placeholder XBlock.
+        """
+        return self.wrap_xblock(block, view_name, Fragment(), context)
+
 
 class StudioPermissionsService(object):
     """
@@ -240,6 +246,7 @@ def _studio_wrap_xblock(xblock, view, frag, context, display_name_only=False):
         template_context = {
             'xblock_context': context,
             'xblock': xblock,
+            'show_preview': context.get('show_preview', True),
             'content': frag.content,
             'is_root': is_root,
             'is_reorderable': is_reorderable,

cms/static/js/spec/views/paged_container_spec.js

 define([ "jquery", "underscore", "js/common_helpers/ajax_helpers", "URI", "js/models/xblock_info",
-    "js/views/paged_container", "js/views/paging_header", "js/views/paging_footer"],
-    function ($, _, AjaxHelpers, URI, XBlockInfo, PagedContainer, PagingHeader, PagingFooter) {
+    "js/views/paged_container", "js/views/paging_header", "js/views/paging_footer", "js/views/xblock"],
+    function ($, _, AjaxHelpers, URI, XBlockInfo, PagedContainer, PagingHeader, PagingFooter, XBlockView) {
 
         var htmlResponseTpl = _.template('' +
-            '<div class="xblock-container-paging-parameters" data-start="<%= start %>" data-displayed="<%= displayed %>" data-total="<%= total %>"/>'
+            '<div class="xblock-container-paging-parameters" ' +
+                'data-start="<%= start %>" ' +
+                'data-displayed="<%= displayed %>" ' +
+                'data-total="<%= total %>" ' +
+                'data-previews="<%= previews %>"></div>'
         );
 
-        function getResponseHtml(options){
+        function getResponseHtml(override_options){
+            var default_options = {
+                start: 0,
+                displayed: PAGE_SIZE,
+                total: PAGE_SIZE + 1,
+                previews: true
+            };
+            var options = _.extend(default_options, override_options);
             return '<div class="xblock" data-request-token="request_token">' +
                 '<div class="container-paging-header"></div>' +
                 htmlResponseTpl(options) +
@@ -14,43 +25,43 @@ define([ "jquery", "underscore", "js/common_helpers/ajax_helpers", "URI", "js/mo
                 '</div>'
         }
 
+        var makePage = function(html_parameters) {
+            return {
+                resources: [],
+                html: getResponseHtml(html_parameters)
+            };
+        };
+
         var PAGE_SIZE = 3;
 
-        var mockFirstPage = {
-            resources: [],
-            html: getResponseHtml({
+        var mockFirstPage = makePage({
                 start: 0,
                 displayed: PAGE_SIZE,
                 total: PAGE_SIZE + 1
-            })
-        };
+        });
 
-        var mockSecondPage = {
-            resources: [],
-            html: getResponseHtml({
+        var mockSecondPage = makePage({
             start: PAGE_SIZE,
             displayed: 1,
             total: PAGE_SIZE + 1
-            })
-        };
+        });
 
-        var mockEmptyPage = {
-            resources: [],
-            html: getResponseHtml({
+        var mockEmptyPage = makePage({
             start: 0,
             displayed: 0,
             total: 0
-            })
-        };
+        });
 
-        var respondWithMockPage = function(requests) {
+        var respondWithMockPage = function(requests, mockPage) {
             var requestIndex = requests.length - 1;
+            if (typeof mockPage == 'undefined') {
                 var request = requests[requestIndex];
                 var url = new URI(request.url);
                 var queryParameters = url.query(true); // Returns an object with each query parameter stored as a value
                 var page = queryParameters.page_number;
-            var response = page === "0" ? mockFirstPage : mockSecondPage;
-            AjaxHelpers.respondWithJson(requests, response, requestIndex);
+                mockPage = page === "0" ? mockFirstPage : mockSecondPage;
+            }
+            AjaxHelpers.respondWithJson(requests, mockPage, requestIndex);
         };
 
         var MockPagingView = PagedContainer.extend({
@@ -65,10 +76,26 @@ define([ "jquery", "underscore", "js/common_helpers/ajax_helpers", "URI", "js/mo
             beforeEach(function () {
                 var feedbackTpl = readFixtures('system-feedback.underscore');
                 setFixtures($("<script>", { id: "system-feedback-tpl", type: "text/template" }).text(feedbackTpl));
-                pagingContainer = new MockPagingView({ page_size: PAGE_SIZE });
+                pagingContainer = new MockPagingView({page_size: PAGE_SIZE});
             });
 
             describe("Container", function () {
+                describe("rendering", function(){
+
+                    it('should set show_previews', function() {
+                       var requests = AjaxHelpers.requests(this);
+                       expect(pagingContainer.collection.showChildrenPreviews).toBe(true); //precondition check
+
+                       pagingContainer.setPage(0);
+                       respondWithMockPage(requests, makePage({previews: false}));
+                       expect(pagingContainer.collection.showChildrenPreviews).toBe(false);
+
+                       pagingContainer.setPage(0);
+                       respondWithMockPage(requests, makePage({previews: true}));
+                       expect(pagingContainer.collection.showChildrenPreviews).toBe(true);
+                   });
+                });
+
                 describe("setPage", function () {
                     it('can set the current page', function () {
                         var requests = AjaxHelpers.requests(this);
@@ -304,8 +331,6 @@ define([ "jquery", "underscore", "js/common_helpers/ajax_helpers", "URI", "js/mo
             });
 
             describe("PagingFooter", function () {
-                var pagingFooter;
-
                 beforeEach(function () {
                     var pagingFooterTpl = readFixtures('paging-footer.underscore');
                     appendSetFixtures($("<script>", { id: "paging-footer-tpl", type: "text/template" }).text(pagingFooterTpl));
@@ -485,5 +510,57 @@ define([ "jquery", "underscore", "js/common_helpers/ajax_helpers", "URI", "js/mo
                     });
                 });
             });
+
+            describe("Previews", function(){
+                describe("Toggle Previews", function(){
+                    var testSendsAjax,
+                        defaultUrl = "/preview/xblock/handler/trigger_previews";
+
+                    testSendsAjax = function (show_previews) {
+                        it("should send " + (!show_previews) + " when showChildrenPreviews was " + show_previews, function(){
+                            var requests = AjaxHelpers.requests(this);
+                            pagingContainer.collection.showChildrenPreviews = show_previews;
+                            pagingContainer.togglePreviews();
+                            AjaxHelpers.expectJsonRequest(requests, 'POST', defaultUrl, { showChildrenPreviews: !show_previews});
+                            AjaxHelpers.respondWithJson(requests, { showChildrenPreviews: !show_previews });
+                        });
+                    };
+                    testSendsAjax(true);
+                    testSendsAjax(false);
+
+                    it("should trigger render on success", function(){
+                        spyOn(pagingContainer, 'render');
+                        var requests = AjaxHelpers.requests(this);
+
+                        pagingContainer.togglePreviews();
+                        AjaxHelpers.respondWithJson(requests, { showChildrenPreviews: true });
+
+                        expect(pagingContainer.render).toHaveBeenCalled();
+                    });
+
+                    it("should not trigger render on failure", function(){
+                        spyOn(pagingContainer, 'render');
+                        var requests = AjaxHelpers.requests(this);
+
+                        pagingContainer.togglePreviews();
+                        AjaxHelpers.respondWithError(requests);
+
+                        expect(pagingContainer.render).not.toHaveBeenCalled();
+                    });
+
+                    it("should send force_render when new block causes page change", function() {
+                        var requests = AjaxHelpers.requests(this);
+                        pagingContainer.setPage(0);
+                        respondWithMockPage(requests);
+                        spyOn(pagingContainer, 'render');
+                        var mockXBlockInfo = new XBlockInfo({id: 'mock-location'});
+                        var mockXBlockView = new XBlockView({model: mockXBlockInfo});
+                        mockXBlockView.model.id = 'mock-location';
+                        pagingContainer.refresh(mockXBlockView, true);
+                        expect(pagingContainer.render).toHaveBeenCalled();
+                        expect(pagingContainer.render.mostRecentCall.args[0].force_render).toEqual('mock-location');
+                    });
+                });
+            });
         });
     });

cms/static/js/spec/views/pages/container_spec.js

@@ -16,6 +16,7 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                     mockXBlockEditorHtml = readFixtures('mock/mock-xblock-editor.underscore'),
                     mockXBlockVisibilityEditorHtml = readFixtures('mock/mock-xblock-visibility-editor.underscore'),
                     PageClass = fixtures.page,
+                    pagedSpecificTests = fixtures.paged_specific_tests,
                     hasVisibilityEditor = fixtures.has_visibility_editor;
 
                 beforeEach(function () {
@@ -305,13 +306,9 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                             }
                         );
 
-                    paginated = function () {
-                        return containerPage instanceof PagedContainerPage;
-                    };
-
                     getDeleteOffset = function () {
                         // Paginated containers will make an additional AJAX request.
-                        return paginated() ? 3 : 2;
+                        return pagedSpecificTests ? 3 : 2;
                     };
 
                     getGroupElement = function () {
@@ -509,6 +506,48 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                         });
                     });
 
+                    describe("Previews", function () {
+
+                        var getButtonIcon, getButtonText;
+
+                        getButtonIcon = function (containerPage) {
+                            return containerPage.$('.action-toggle-preview i');
+                        };
+
+                        getButtonText = function (containerPage) {
+                            return containerPage.$('.action-toggle-preview .preview-text').text().trim();
+                        };
+
+                        if (pagedSpecificTests) {
+                            it('has no text on the preview button to start with', function () {
+                                containerPage = getContainerPage();
+                                expect(getButtonIcon(containerPage)).toHaveClass('fa-refresh');
+                                expect(getButtonIcon(containerPage).parent()).toHaveClass('is-hidden');
+                                expect(getButtonText(containerPage)).toBe("");
+                            });
+
+                            function updatePreviewButtonTest(show_previews, expected_text) {
+                                it('can set preview button to "' + expected_text + '"', function () {
+                                    containerPage = getContainerPage();
+                                    containerPage.updatePreviewButton(show_previews);
+                                    expect(getButtonText(containerPage)).toBe(expected_text);
+                                });
+                            }
+
+                            updatePreviewButtonTest(true, 'Hide Previews');
+                            updatePreviewButtonTest(false, 'Show Previews');
+
+                            it('triggers underlying view togglePreviews when preview button clicked', function () {
+                                containerPage = getContainerPage();
+                                containerPage.render();
+                                spyOn(containerPage.xblockView, 'togglePreviews');
+
+                                containerPage.$('.toggle-preview-button').click();
+                                expect(containerPage.xblockView.togglePreviews).toHaveBeenCalled();
+                            });
+                        }
+                    });
+
                     describe('createNewComponent ', function () {
                         var clickNewComponent;
 
@@ -591,6 +630,7 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                         });
                     });
                 });
+
             });
         }
 
@@ -601,7 +641,8 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                 page: ContainerPage,
                 initial: 'mock/mock-container-xblock.underscore',
                 add_response: 'mock/mock-xblock.underscore',
-                has_visibility_editor: true
+                has_visibility_editor: true,
+                paged_specific_tests: false
             }
         );
 
@@ -612,7 +653,8 @@ define(["jquery", "underscore", "underscore.string", "js/common_helpers/ajax_hel
                 page: PagedContainerPage,
                 initial: 'mock/mock-container-paged-xblock.underscore',
                 add_response: 'mock/mock-xblock-paged.underscore',
-                has_visibility_editor: false
+                has_visibility_editor: false,
+                paged_specific_tests: true
             }
         );
     });

cms/static/js/views/paged_container.js

-define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettext",
+define(["jquery", "underscore", "js/views/utils/view_utils", "js/views/container", "js/utils/module", "gettext",
         "js/views/feedback_notification", "js/views/paging_header", "js/views/paging_footer", "js/views/paging_mixin"],
-    function ($, _, ContainerView, ModuleUtils, gettext, NotificationView, PagingHeader, PagingFooter, PagingMixin) {
+    function ($, _, ViewUtils, ContainerView, ModuleUtils, gettext, NotificationView, PagingHeader, PagingFooter, PagingMixin) {
         var PagedContainerView = ContainerView.extend(PagingMixin).extend({
             initialize: function(options){
                 var self = this;
@@ -24,7 +24,9 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                     bind: function() {},
                     // size() on backbone collections shows how many objects are in the collection, or in the case
                     // of paginator, on the current page.
-                    size: function() { return self.collection._size; }
+                    size: function() { return self.collection._size; },
+                    // Toggles the functionality for showing and hiding child previews.
+                    showChildrenPreviews: true
                 };
             },
 
@@ -47,21 +49,29 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                     url: decodeURIComponent(xblockUrl) + "/" + view,
                     type: 'GET',
                     cache: false,
-                    data: this.getRenderParameters(options.page_number),
+                    data: this.getRenderParameters(options.page_number, options.force_render),
                     headers: { Accept: 'application/json' },
                     success: function(fragment) {
                         self.handleXBlockFragment(fragment, options);
                         self.processPaging({ requested_page: options.page_number });
+                        self.page.updatePreviewButton(self.collection.showChildrenPreviews);
                         self.page.renderAddXBlockComponents();
+                        if (options.force_render) {
+                            var target = $('.studio-xblock-wrapper[data-locator="' + options.force_render + '"]');
+                            // Scroll us to the element with a little buffer at the top for context.
+                            ViewUtils.setScrollOffset(target, ($(window).height() * .10));
+                        }
                     }
                 });
             },
 
-            getRenderParameters: function(page_number) {
+            getRenderParameters: function(page_number, force_render) {
+                // Options should at least contain page_number.
                 return {
                     page_size: this.page_size,
                     enable_paging: true,
-                    page_number: page_number
+                    page_number: page_number,
+                    force_render: force_render
                 };
             },
 
@@ -70,8 +80,10 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                 return Math.ceil(total_count / this.page_size);
             },
 
-            setPage: function(page_number) {
-                this.render({ page_number: page_number});
+            setPage: function(page_number, additional_options) {
+                additional_options = additional_options || {};
+                var options = _.extend({page_number: page_number}, additional_options);
+                this.render(options);
             },
 
             processPaging: function(options){
@@ -80,13 +92,15 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                 var $element = this.$el.find('.xblock-container-paging-parameters'),
                     total = $element.data('total'),
                     displayed = $element.data('displayed'),
-                    start = $element.data('start');
+                    start = $element.data('start'),
+                    previews = $element.data('previews');
 
                 this.collection.currentPage = options.requested_page;
                 this.collection.totalCount = total;
                 this.collection.totalPages = this.getPageCount(total);
                 this.collection.start = start;
                 this.collection._size = displayed;
+                this.collection.showChildrenPreviews = previews;
 
                 this.processPagingHeaderAndFooter();
             },
@@ -112,8 +126,21 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                 this.pagingFooter.render();
             },
 
-            refresh: function(block_added) {
-                if (block_added) {
+            refresh: function(xblockView, block_added, is_duplicate) {
+                if (!block_added) {
+                    return
+                }
+                if (is_duplicate) {
+                    // Duplicated blocks can be inserted onto the current page.
+                    var xblock = xblockView.xblock.element.parents(".studio-xblock-wrapper").first();
+                    var all_xblocks = xblock.parent().children(".studio-xblock-wrapper");
+                    var index = all_xblocks.index(xblock);
+                    if ((index + 1 <= this.page_size) && (all_xblocks.length > this.page_size)) {
+                        // Pop the last XBlock off the bottom.
+                        all_xblocks[all_xblocks.length - 1].remove();
+                        return
+                    }
+                }
                 this.collection.totalCount += 1;
                 this.collection._size +=1;
                 if (this.collection.totalCount == 1) {
@@ -121,15 +148,23 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
                     return
                 }
                 this.collection.totalPages = this.getPageCount(this.collection.totalCount);
-                    var new_page = this.collection.totalPages - 1;
+                var target_page = this.collection.totalPages - 1;
                 // If we're on a new page due to overflow, or this is the first item, set the page.
-                    if (((this.collection.currentPage) != new_page) || this.collection.totalCount == 1) {
-                        this.setPage(new_page);
+                if (((this.collection.currentPage) != target_page) || this.collection.totalCount == 1) {
+                    var force_render = xblockView.model.id;
+                    if (is_duplicate) {
+                        // The duplicate should be on the next page if we've gotten here.
+                        target_page = this.collection.currentPage + 1;
+                    }
+                    this.setPage(
+                        target_page,
+                        {force_render: force_render}
+                    );
+
                 } else {
                     this.pagingHeader.render();
                     this.pagingFooter.render();
                 }
-                }
             },
 
             acknowledgeXBlockDeletion: function (locator){
@@ -157,6 +192,19 @@ define(["jquery", "underscore", "js/views/container", "js/utils/module", "gettex
 
             sortDisplayName: function() {
                 return gettext("Date added");  // TODO add support for sorting
+            },
+
+            togglePreviews: function(){
+                var self = this,
+                    xblockUrl = this.model.url();
+                return $.ajax({
+                    // No runtime, so can't get this via the handler() call.
+                    url: '/preview' + decodeURIComponent(xblockUrl) + "/handler/trigger_previews",
+                    type: 'POST',
+                    data: JSON.stringify({ showChildrenPreviews: !this.collection.showChildrenPreviews}),
+                    dataType: 'json'
+                })
+                .then(self.render).promise();
             }
         });
 

cms/static/js/views/pages/container.js

@@ -140,8 +140,8 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                 return this.xblockView.model.urlRoot;
             },
 
-            onXBlockRefresh: function(xblockView, block_added) {
-                this.xblockView.refresh(block_added);
+            onXBlockRefresh: function(xblockView, block_added, is_duplicate) {
+                this.xblockView.refresh(xblockView, block_added, is_duplicate);
                 // Update publish and last modified information from the server.
                 this.model.fetch();
             },
@@ -214,7 +214,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                         parent_locator: parentLocator
                     });
                 return $.postJSON(this.getURLRoot() + '/', requestData,
-                    _.bind(this.onNewXBlock, this, placeholderElement, scrollOffset))
+                    _.bind(this.onNewXBlock, this, placeholderElement, scrollOffset, false))
                     .fail(function() {
                         // Remove the placeholder if the update failed
                         placeholderElement.remove();
@@ -237,7 +237,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                                 parent_locator: parentElement.data('locator')
                             };
                         return $.postJSON(self.getURLRoot() + '/', requestData,
-                            _.bind(self.onNewXBlock, self, placeholderElement, scrollOffset))
+                            _.bind(self.onNewXBlock, self, placeholderElement, scrollOffset, true))
                             .fail(function() {
                                 // Remove the placeholder if the update failed
                                 placeholderElement.remove();
@@ -269,10 +269,10 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                 this.model.fetch();
             },
 
-            onNewXBlock: function(xblockElement, scrollOffset, data) {
+            onNewXBlock: function(xblockElement, scrollOffset, is_duplicate, data) {
                 ViewUtils.setScrollOffset(xblockElement, scrollOffset);
                 xblockElement.data('locator', data.locator);
-                return this.refreshXBlock(xblockElement, true);
+                return this.refreshXBlock(xblockElement, true, is_duplicate);
             },
 
             /**
@@ -282,14 +282,14 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
              * @param element An element representing the xblock to be refreshed.
              * @param block_added Flag to indicate that new block has been just added.
              */
-            refreshXBlock: function(element, block_added) {
+            refreshXBlock: function(element, block_added, is_duplicate) {
                 var xblockElement = this.findXBlockElement(element),
                     parentElement = xblockElement.parent(),
                     rootLocator = this.xblockView.model.id;
                 if (xblockElement.length === 0 || xblockElement.data('locator') === rootLocator) {
                     this.render({refresh: true, block_added: block_added});
                 } else if (parentElement.hasClass('reorderable-container')) {
-                    this.refreshChildXBlock(xblockElement, block_added);
+                    this.refreshChildXBlock(xblockElement, block_added, is_duplicate);
                 } else {
                     this.refreshXBlock(this.findXBlockElement(parentElement));
                 }
@@ -303,7 +303,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
              * refreshing.
              * @returns {jQuery promise} A promise representing the complete operation.
              */
-            refreshChildXBlock: function(xblockElement, block_added) {
+            refreshChildXBlock: function(xblockElement, block_added, is_duplicate) {
                 var self = this,
                     xblockInfo,
                     TemporaryXBlockView,
@@ -329,7 +329,7 @@ define(["jquery", "underscore", "gettext", "js/views/pages/base_page", "js/views
                 });
                 return temporaryView.render({
                     success: function() {
-                        self.onXBlockRefresh(temporaryView, block_added);
+                        self.onXBlockRefresh(temporaryView, block_added, is_duplicate);
                         temporaryView.unbind();  // Remove the temporary view
                     }
                 });

cms/static/js/views/pages/paged_container.js

@@ -6,11 +6,14 @@ define(["jquery", "underscore", "gettext", "js/views/pages/container", "js/views
         'use strict';
         var PagedXBlockContainerPage = XBlockContainerPage.extend({
 
+            events: {"click .toggle-preview-button": "toggleChildrenPreviews"},
             defaultViewClass: PagedContainerView,
             components_on_init: false,
 
             initialize: function (options){
+                this.events = _.extend({}, XBlockContainerPage.prototype.events, this.events);
                 this.page_size = options.page_size || 10;
+                this.showChildrenPreviews = options.showChildrenPreviews || true;
                 XBlockContainerPage.prototype.initialize.call(this, options);
             },
 
@@ -21,16 +24,28 @@ define(["jquery", "underscore", "gettext", "js/views/pages/container", "js/views
                });
             },
 
-            refreshXBlock: function(element, block_added) {
+            refreshXBlock: function(element, block_added, is_duplicate) {
                 var xblockElement = this.findXBlockElement(element),
                     rootLocator = this.xblockView.model.id;
                 if (xblockElement.length === 0 || xblockElement.data('locator') === rootLocator) {
                     this.render({refresh: true, block_added: block_added});
                 } else {
-                    this.refreshChildXBlock(xblockElement, block_added);
-                }
+                    this.refreshChildXBlock(xblockElement, block_added, is_duplicate);
                 }
+            },
+
+            toggleChildrenPreviews: function(xblockElement) {
+                xblockElement.preventDefault();
+                this.xblockView.togglePreviews();
+            },
+
+            updatePreviewButton: function(show_previews){
+                var text = (show_previews) ? gettext('Hide Previews') : gettext('Show Previews'),
+                    button = $('.nav-actions .button-toggle-preview');
 
+                this.$(".preview-text", button).text(text);
+                this.$('.toggle-preview-button').removeClass("is-hidden");
+            }
         });
         return PagedXBlockContainerPage;
     });

cms/static/sass/elements/_xblocks.scss

@@ -356,6 +356,10 @@
       margin-bottom: 0;
       border-bottom: 1px solid $gray-l4;
       background-color: $gray-l6;
+      &.is-collapsed {
+        border-bottom: 0;
+        border-radius: 3px;
+      }
     }
 
     .xblock-render {

cms/templates/js/mock/mock-container-page.underscore

@@ -39,6 +39,12 @@
                             <span class="action-button-text">Add Component</span>
                         </a>
                    </li>
+                   <li class="action-item action-toggle-preview nav-item">
+                       <a href="#" class="button button-toggle-preview action-button toggle-preview-button is-hidden">
+                           <i class="icon fa fa-refresh"></i>
+                           <span class="action-button-text preview-text"></span>
+                       </a>
+                   </li>
                 </ul>
             </nav>
         </header>

cms/templates/library.html

@@ -27,7 +27,8 @@ from django.utils.translation import ugettext as _
             {
                 isUnitPage: false,
                 page_size: 10,
-                canEdit: ${"true" if can_edit else "false"}
+                canEdit: ${"true" if can_edit else "false"},
+                showChildrenPreviews: ${'true' if show_children_previews else 'false'}
             }
         );
     });
@@ -54,6 +55,12 @@ from django.utils.translation import ugettext as _
                         <i class="icon fa fa-plus icon-inline"></i> <span class="action-button-text">${_("Add Component")}</span>
                     </a>
                 </li>
+                <li class="action-item action-toggle-preview nav-item">
+                    <a href="#" class="button button-toggle-preview action-button toggle-preview-button is-hidden">
+                        <i class="icon fa fa-refresh"></i>
+                        <span class="action-button-text preview-text"></span>
+                    </a>
+                </li>
             </ul>
         </nav>
     </header>

cms/templates/studio_xblock_wrapper.html

@@ -47,7 +47,11 @@ messages = json.dumps(xblock.validate().to_json())
 % endif
 
 <header class="xblock-header xblock-header-${xblock.category}">
-    <div class="xblock-header-primary">
+    <div class="xblock-header-primary
+    % if not show_preview:
+        is-collapsed
+    % endif
+    ">
         <div class="header-details">
             % if show_inline:
             <a href="#" data-tooltip="${_('Expand or Collapse')}" class="action expand-collapse collapse">
@@ -128,14 +132,17 @@ messages = json.dumps(xblock.validate().to_json())
     <div class="wrapper-xblock-message xblock-validation-messages" data-locator="${xblock.location | h}"/>
 % endif
 
-% if is_root or not xblock_url:
+% if show_preview:
+    % if is_root or not xblock_url:
         <article class="xblock-render">
         ${content}
         </article>
-% else:
+    % else:
         <div class="xblock-message-area">
         ${content}
-% endif
+        </div>
+    % endif
+ % endif   
 
 % if not is_root:
     </section>

common/lib/xmodule/xmodule/library_root_xblock.py

@@ -3,11 +3,12 @@
 """
 import logging
 
-from xblock.core import XBlock
-from xblock.fields import Scope, String, List
-from xblock.fragment import Fragment
 from xmodule.studio_editable import StudioEditableModule
 
+from xblock.fields import Scope, String, List, Boolean
+from xblock.fragment import Fragment
+from xblock.core import XBlock
+
 log = logging.getLogger(__name__)
 
 # Make '_' a no-op so we can scrape strings
@@ -32,6 +33,12 @@ class LibraryRoot(XBlock):
         scope=Scope.settings,
         xml_node=True,
     )
+    show_children_previews = Boolean(
+        display_name="Hide children preview",
+        help="Choose if preview of library contents is shown",
+        scope=Scope.user_state,
+        default=True
+    )
     has_children = True
     has_author_view = True
 
@@ -69,10 +76,22 @@ class LibraryRoot(XBlock):
 
         children_to_show = self.children[item_start:item_end]  # pylint: disable=no-member
 
+        force_render = context.get('force_render', None)
+
         for child_key in children_to_show:  # pylint: disable=E1101
+            # Children must have a separate context from the library itself. Make a copy.
+            child_context = context.copy()
+            child_context['show_preview'] = self.show_children_previews
             child = self.runtime.get_block(child_key)
             child_view_name = StudioEditableModule.get_preview_view_name(child)
-            rendered_child = self.runtime.render_child(child, child_view_name, context)
+
+            if unicode(child.location) == force_render:
+                child_context['show_preview'] = True
+
+            if child_context['show_preview']:
+                rendered_child = self.runtime.render_child(child, child_view_name, child_context)
+            else:
+                rendered_child = self.runtime.render_child_placeholder(child, child_view_name, child_context)
             fragment.add_frag_resources(rendered_child)
 
             contents.append({
@@ -87,7 +106,8 @@ class LibraryRoot(XBlock):
                 'can_add': can_add,
                 'first_displayed': item_start,
                 'total_children': children_count,
-                'displayed_children': len(children_to_show)
+                'displayed_children': len(children_to_show),
+                'previews': self.show_children_previews
             })
         )
 
@@ -106,3 +126,9 @@ class LibraryRoot(XBlock):
         Always returns the raw 'library' field from the key.
         """
         return self.scope_ids.usage_id.course_key.library
+
+    @XBlock.json_handler
+    def trigger_previews(self, request_body, suffix):  # pylint: disable=unused-argument
+        """ Enable or disable previews in studio for library children. """
+        self.show_children_previews = request_body.get('showChildrenPreviews', self.show_children_previews)
+        return {'showChildrenPreviews': self.show_children_previews}

common/test/acceptance/pages/studio/container.py

@@ -500,6 +500,12 @@ class XBlockWrapper(PageObject):
         """
         self.q(css=self._bounded_selector('span.message-text a')).first.click()
 
+    def is_placeholder(self):
+        """
+        Checks to see if the XBlock is rendered as a placeholder without a preview.
+        """
+        return not self.q(css=self._bounded_selector('.wrapper-xblock article')).present
+
     @property
     def group_configuration_link_name(self):
         """

common/test/acceptance/pages/studio/library.py

@@ -69,6 +69,25 @@ class LibraryEditPage(LibraryPage, PaginatedMixin):
         """
         return self._get_xblocks()
 
+    def are_previews_showing(self):
+        """
+        Determines whether or not previews are showing for XBlocks
+        """
+        return all([not xblock.is_placeholder() for xblock in self.xblocks])
+
+    def toggle_previews(self):
+        """
+        Clicks the preview toggling button and waits for the previews to appear or disappear.
+        """
+        toggle = not self.are_previews_showing()
+        self.q(css='.toggle-preview-button').click()
+        EmptyPromise(
+            lambda: self.are_previews_showing() == toggle,
+            'Preview is visible: %s' % toggle,
+            timeout=30
+        ).fulfill()
+        self.wait_until_ready()
+
     def click_duplicate_button(self, xblock_id):
         """
         Click on the duplicate button for the given XBlock

common/test/acceptance/tests/studio/test_studio_library.py

@@ -51,7 +51,6 @@ class LibraryEditPageTest(StudioLibraryTest):
         Then one XBlock is displayed
         And displayed XBlock are second one
         """
-        self.browser.save_screenshot('library_page')
         self.assertEqual(len(self.lib_page.xblocks), 0)
 
         # Create a new block:
@@ -343,6 +342,161 @@ class LibraryNavigationTest(StudioLibraryTest):
         self.assertEqual(self.lib_page.xblocks[-1].name, '11')
         self.assertEqual(self.lib_page.get_page_number(), '1')
 
+    def test_previews(self):
+        """
+        Scenario: Ensure the user is able to hide previews of XBlocks.
+        Given that I have a library in Studio with 40 XBlocks
+        Then previews are visible
+        And when I click the toggle previews button
+        Then the previews will not be visible
+        And when I click the toggle previews button
+        Then the previews are visible
+        """
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        self.assertFalse(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        self.assertTrue(self.lib_page.are_previews_showing())
+
+    def test_previews_navigation(self):
+        """
+        Scenario: Ensure preview settings persist across navigation.
+        Given that I have a library in Studio with 40 XBlocks
+        Then previews are visible
+        And when I click the toggle previews button
+        And click the next page button
+        Then the previews will not be visible
+        And the first XBlock will be the 11th one
+        And the last XBlock will be the 20th one
+        And when I click the toggle previews button
+        And I click the previous page button
+        Then the previews will be visible
+        And the first XBlock will be the first one
+        And the last XBlock will be the 11th one
+        """
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        # Which set of arrows shouldn't matter for this test.
+        self.lib_page.move_forward('top')
+        self.assertFalse(self.lib_page.are_previews_showing())
+        self.assertEqual(self.lib_page.xblocks[0].name, '11')
+        self.assertEqual(self.lib_page.xblocks[-1].name, '20')
+        self.lib_page.toggle_previews()
+        self.lib_page.move_back('top')
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.assertEqual(self.lib_page.xblocks[0].name, '1')
+        self.assertEqual(self.lib_page.xblocks[-1].name, '10')
+
+    def test_preview_state_persistance(self):
+        """
+        Scenario: Ensure preview state persists between page loads.
+        Given that I have a library in Studio with 40 XBlocks
+        Then previews are visible
+        And when I click the toggle previews button
+        And I revisit the page
+        Then the previews will not be visible
+        """
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        self.lib_page.visit()
+        self.lib_page.wait_until_ready()
+        self.assertFalse(self.lib_page.are_previews_showing())
+
+    def test_preview_add_xblock(self):
+        """
+        Scenario: Ensure previews are shown when adding new blocks, regardless of preview setting.
+        Given that I have a library in Studio with 40 XBlocks
+        Then previews are visible
+        And when I click the toggle previews button
+        Then the previews will not be visible
+        And when I add an XBlock
+        Then I will be on the 5th page
+        And the XBlock will have loaded a preview
+        And when I revisit the library
+        And I go to the 5th page
+        Then the top XBlock will be the one I added
+        And it will not have a preview
+        And when I add an XBlock
+        Then the XBlock I added will have a preview
+        And the top XBlock will not have one.
+        """
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        self.assertFalse(self.lib_page.are_previews_showing())
+        add_component(self.lib_page, "problem", "Checkboxes")
+        self.assertEqual(self.lib_page.get_page_number(), '5')
+        first_added = self.lib_page.xblocks[0]
+        self.assertIn("Checkboxes", first_added.name)
+        self.assertFalse(self.lib_page.xblocks[0].is_placeholder())
+        self.lib_page.visit()
+        self.lib_page.wait_until_ready()
+        self.lib_page.go_to_page(5)
+        self.assertTrue(self.lib_page.xblocks[0].is_placeholder())
+        add_component(self.lib_page, "problem", "Multiple Choice")
+        # DOM has detatched the element since last assignment
+        first_added = self.lib_page.xblocks[0]
+        second_added = self.lib_page.xblocks[1]
+        self.assertIn("Multiple Choice", second_added.name)
+        self.assertFalse(second_added.is_placeholder())
+        self.assertTrue(first_added.is_placeholder())
+
+    def test_edit_with_preview(self):
+        """
+        Scenario: Editing an XBlock should show me a preview even if previews are hidden.
+        Given that I have a library in Studio with 40 XBlocks
+        Then previews are visible
+        And when I click the toggle previews button
+        Then the previews will not be visible
+        And when I edit the first XBlock
+        Then the first XBlock will show a preview
+        And the other XBlocks will still be placeholders
+        """
+        self.assertTrue(self.lib_page.are_previews_showing())
+        self.lib_page.toggle_previews()
+        self.assertFalse(self.lib_page.are_previews_showing())
+        target = self.lib_page.xblocks[0]
+        target.edit()
+        target.save_settings()
+        self.assertFalse(target.is_placeholder())
+        self.assertTrue(all([xblock.is_placeholder() for xblock in self.lib_page.xblocks[1:]]))
+
+    def test_duplicate_xblock_pagination(self):
+        """
+        Scenario: Duplicating an XBlock should not shift the page if the XBlock is not at the end.
+        Given that I have a library in Studio with 40 XBlocks
+        When I duplicate the third XBlock
+        Then the page should not change
+        And the duplicate XBlock should be there
+        And it should show a preview
+        And there should not be more than 10 XBlocks visible.
+        """
+        third_block_id = self.lib_page.xblocks[2].locator
+        self.lib_page.click_duplicate_button(third_block_id)
+        self.lib_page.wait_until_ready()
+        target = self.lib_page.xblocks[3]
+        self.assertIn('Duplicate', target.name)
+        self.assertFalse(target.is_placeholder())
+        self.assertEqual(len(self.lib_page.xblocks), 10)
+
+    def test_duplicate_xblock_pagination_end(self):
+        """
+        Scenario: Duplicating an XBlock if it's the last one should bring me to the next page with a preview.
+        Given that I have a library in Studio with 40 XBlocks
+        And when I hide previews
+        And I duplicate the last XBlock
+        The page should change to page 2
+        And the duplicate XBlock should be the first XBlock
+        And it should not be a placeholder
+        """
+        self.lib_page.toggle_previews()
+        last_block_id = self.lib_page.xblocks[-1].locator
+        self.lib_page.click_duplicate_button(last_block_id)
+        self.lib_page.wait_until_ready()
+        self.assertEqual(self.lib_page.get_page_number(), '2')
+        target_block = self.lib_page.xblocks[0]
+        self.assertIn('Duplicate', target_block.name)
+        self.assertFalse(target_block.is_placeholder())
+
 
 class LibraryUsersPageTest(StudioLibraryTest):
     """

lms/templates/studio_render_paged_children_view.html

@@ -8,7 +8,12 @@
 </script>
 % endfor
 
-<div class="xblock-container-paging-parameters" data-start="${first_displayed}" data-displayed="${displayed_children}" data-total="${total_children}"></div>
+<div class="xblock-container-paging-parameters"
+     data-start="${first_displayed}"
+     data-displayed="${displayed_children}"
+     data-total="${total_children}"
+     data-previews="${'true' if previews else 'false'}"
+></div>
 
 <div class="container-paging-header"></div>