Merge pull request #250 from PolymerElements/issue-243

Fix #243
PolymerElements · Jun 1, 2016 · 46cca14 · 46cca14
2 parents d3cef7d + 5342ec5
commit 46cca14
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Showing 2 changed files with 46 additions and 60 deletions.
diff --git a/iron-list.html b/iron-list.html
@@ -620,7 +620,6 @@
             if (physicalOffset > this._scrollPosition) {
               return this.grid ? vidx - (vidx % this._itemsPerRow) : vidx;
             }
-
             // Handle a partially rendered final row in grid mode
             if (this.grid && this._virtualCount - 1 === vidx) {
               return vidx - (vidx % this._itemsPerRow);
@@ -639,21 +638,17 @@
       if (this._lastVisibleIndexVal === null) {
         if (this.grid) {
           var lastIndex = this.firstVisibleIndex + this._estRowsInView * this._itemsPerRow - 1;
-          this._lastVisibleIndexVal = lastIndex > this._virtualCount ? this._virtualCount : lastIndex;
+          this._lastVisibleIndexVal = Math.min(this._virtualCount, lastIndex);
         } else {
           var physicalOffset = this._physicalTop;
-
           this._iterateItems(function(pidx, vidx) {
-            physicalOffset += this._getPhysicalSizeIncrement(pidx);
-
-            if(physicalOffset <= this._scrollBottom) {
-              if (this.grid) {
-                var lastIndex = vidx - vidx % this._itemsPerRow + this._itemsPerRow - 1;
-                this._lastVisibleIndexVal = lastIndex > this._virtualCount ? this._virtualCount : lastIndex;
-              } else {
-                this._lastVisibleIndexVal = vidx;
-              }
+            if (physicalOffset < this._scrollBottom) {
+              this._lastVisibleIndexVal = vidx;
+            } else {
+              // Break _iterateItems
+              return true;
             }
+            physicalOffset += this._getPhysicalSizeIncrement(pidx);
           });
         }
       }
@@ -1067,10 +1062,11 @@
         this._virtualCount = this.items ? this.items.length : 0;
         this._collection = this.items ? Polymer.Collection.get(this.items) : null;
         this._physicalIndexForKey = {};
+        this._firstVisibleIndexVal = null;
+        this._lastVisibleIndexVal = null;
 
         this._resetScrollPosition(0);
         this._removeFocusedItem();
-
         // create the initial physical items
         if (!this._physicalItems) {
           this._physicalCount = Math.max(1, Math.min(DEFAULT_PHYSICAL_COUNT, this._virtualCount));
@@ -1081,6 +1077,7 @@
         this._physicalStart = 0;
 
       } else if (change.path === 'items.splices') {
+
         this._adjustVirtualIndex(change.value.indexSplices);
         this._virtualCount = this.items ? this.items.length : 0;
 

diff --git a/test/basic.html b/test/basic.html
@@ -81,55 +81,44 @@
       });
     });
 
-    test('first visible index', function(done) {
+    test('first visible index', function() {
       container.data = buildDataSet(100);
+      Polymer.dom.flush();
+      assert.equal(list.firstVisibleIndex, 0);
+      list.scroll(0, container.itemHeight * 10);
+      list.fire('scroll');
+      assert.equal(list.firstVisibleIndex, 10);
+      list.scroll(0, container.itemHeight * 50);
+      list.fire('scroll');
+      assert.equal(list.firstVisibleIndex, 50);
+      list.scrollToIndex(60);
+      Polymer.dom.flush();
+      assert.equal(list.firstVisibleIndex, 60);
+      list.scrollToIndex(0);
+      Polymer.dom.flush();
+      assert.equal(list.firstVisibleIndex, 0);
+    });
 
-      flush(function() {
-        var setSize = list.items.length;
-        var rowHeight = container.itemHeight;
-        var viewportHeight = list.offsetHeight;
-        var scrollToItem;
-
-        function checkFirstVisible() {
-          assert.equal(list.firstVisibleIndex, scrollToItem);
-          assert.equal(getFirstItemFromList(list).textContent, scrollToItem);
-        }
-
-        function checkLastVisible() {
-          var visibleItemsCount = Math.floor(viewportHeight / rowHeight);
-          assert.equal(list.lastVisibleIndex, scrollToItem + visibleItemsCount - 1);
-          assert.equal(getLastItemFromList(list).textContent, scrollToItem + visibleItemsCount - 1);
-        }
-
-        function doneScrollDown() {
-          checkFirstVisible();
-          checkLastVisible();
-          scrollToItem = 1;
-          flush(function() {
-            simulateScroll({
-              list: list,
-              contribution: rowHeight,
-              target: scrollToItem*rowHeight,
-              onScrollEnd: doneScrollUp
-            });
-          });
-        }
-
-        function doneScrollUp() {
-          checkFirstVisible();
-          checkLastVisible();
-          done();
-        }
-        scrollToItem = 50;
-
-        simulateScroll({
-          list: list,
-          contribution: 50,
-          target: scrollToItem*rowHeight,
-          onScrollEnd: doneScrollDown
-        });
-
-      });
+    test('last visible index', function() {
+      container.data = buildDataSet(1);
+      container.itemHeight = 1000;
+      Polymer.dom.flush();
+      assert.equal(list.lastVisibleIndex, 0);
+      container.data = buildDataSet(2);
+      container.itemHeight = 50;
+      Polymer.dom.flush();
+      assert.equal(list.lastVisibleIndex, 1);
+      container.data = buildDataSet(10);
+      Polymer.dom.flush();
+      list.scrollToIndex(8);
+      Polymer.dom.flush();
+      assert.equal(list.lastVisibleIndex, 9);
+      container.itemHeight = 50;
+      container.data = buildDataSet(100);
+      Polymer.dom.flush();
+      list.scroll(0, 100);
+      list.fire('scroll');
+      assert.equal(list.lastVisibleIndex, ((list._scrollTop + container.listHeight) / container.itemHeight) - 1);
     });
 
     test('scroll to index', function(done) {