update tree if items are added or removed - fix #278

examples/example1/src/example1.d

@@ -580,7 +580,7 @@ extern (C) int UIAppMain(string[] args) {
             gbgrid.addChild(grid);
             line4.addChild(gbgrid);
 
-            GroupBox gbtree = new GroupBox("tree", "TreeWidget"d, Orientation.Horizontal);
+            GroupBox gbtree = new GroupBox("tree", "TreeWidget"d, Orientation.Vertical);
             auto tree = new TreeWidget("gbtree");
             //tree.layoutWidth(WRAP_CONTENT).layoutHeight(FILL_PARENT);
             tree.maxHeight(200.pointsToPixels);
@@ -606,6 +606,38 @@ extern (C) int UIAppMain(string[] args) {
             tree3.newChild("g3_5", "Group 3 item 5"d);
             tree3.newChild("g3_6", "Group 3 item 6"d);
             gbtree.addChild(tree);
+            tree.items.selectItem(tree1);
+            // test adding new tree items
+            HorizontalLayout newTreeItem = new HorizontalLayout();
+            newTreeItem.layoutWidth = FILL_PARENT;
+            EditLine edNewTreeItem = new EditLine("newTreeItem", "new item"d);
+            edNewTreeItem.layoutWidth = FILL_PARENT;
+            Button btnAddItem = new Button("btnAddTreeItem", "Add"d);
+            Button btnRemoveItem = new Button("btnRemoveTreeItem", "Remove"d);
+            newTreeItem.addChild(edNewTreeItem);
+            newTreeItem.addChild(btnAddItem);
+            newTreeItem.addChild(btnRemoveItem);
+            btnAddItem.click = delegate(Widget source) {
+                import std.random;
+                dstring label = edNewTreeItem.text;
+                string id = "item%d".format(uniform(1000000, 9999999, rndGen));
+                TreeItem item = tree.items.selectedItem;
+                if (item) {
+                    Log.d("Creating new tree item ", id, " ", label);
+                    TreeItem newItem = new TreeItem(id, label);
+                    item.addChild(newItem);
+                }
+                return true;
+            };
+            btnRemoveItem.click = delegate(Widget source) {
+                TreeItem item = tree.items.selectedItem;
+                if (item) {
+                    Log.d("Removing tree item ", item.id, " ", item.text);
+                    item.parent.removeChild(item);
+                }
+                return true;
+            };
+            gbtree.addChild(newTreeItem);
             line4.addChild(gbtree);
 
             controls.addChild(line4);

src/dlangui/core/collections.d

@@ -242,6 +242,7 @@ struct ObjectList(T) {
     protected int _count;
     /** returns count of items */
     @property int count() const { return _count; }
+    alias length = count;
     /** get item by index */
     T get(int index) {
         assert(index >= 0 && index < _count, "child index out of range");
@@ -280,7 +281,7 @@ struct ObjectList(T) {
         if (item is null)
             return -1;
         for (int i = 0; i < _count; i++)
-            if (_list[i] == item)
+            if (_list[i] is item)
                 return i;
         return -1;
     }

src/dlangui/widgets/tree.d

@@ -253,32 +253,50 @@ class TreeItem {
     /// returns child by index
     TreeItem child(int index) { return _children.get(index); }
     /// adds child, returns added item
-    TreeItem addChild(TreeItem item) {
+    TreeItem addChild(TreeItem item, int index = -1) {
-        return _children.add(item).parent(this).level(_level + 1);
+        TreeItem res = _children.insert(item, index).parent(this).level(_level + 1);
+        root.onUpdate(res);
+        return res;
     }
     /// removes child, returns removed item
     TreeItem removeChild(int index) {
+        if (index < 0 || index >= _children.count)
+            return null;
         TreeItem res = _children.remove(index);
-        if (res !is null)
+        TreeItem newSelection = null;
+        if (res !is null) {
             res.parent = null;
+            if (root && root.selectedItem is res) {
+                if (index < _children.count)
+                    newSelection = _children[index];
+                else if (index > 0)
+                    newSelection = _children[index - 1];
+                else
+                    newSelection = this;
+            }
+        }
+        root.selectItem(newSelection);
+        root.onUpdate(this);
         return res;
     }
+    /// removes child by reference, returns removed item
+    TreeItem removeChild(TreeItem child) {
+        TreeItem res = null;
+        int index = _children.indexOf(child);
+        return removeChild(index);
+    }
     /// removes child by ID, returns removed item
     TreeItem removeChild(string ID) {
         TreeItem res = null;
         int index = _children.indexOf(ID);
-        if (index < 0)
+        return removeChild(index);
-            return null;
-        res = _children.remove(index);
-        if (res !is null)
-            res.parent = null;
-        return res;
     }
     /// returns index of widget in child list, -1 if passed widget is not a child of this widget
     int childIndex(TreeItem item) { return _children.indexOf(item); }
     /// notify listeners
     protected void onUpdate(TreeItem item) {
-        root.onUpdate(item);
+        if (root)
+            root.onUpdate(item);
     }
     protected void toggleExpand(TreeItem item) {
         root.toggleExpand(item);