lists, partial implementation

src/dlangui/widgets/controls.d

@@ -370,6 +370,7 @@ class ScrollBar : WidgetGroup, OnClickHandler {
 
     protected void layoutButtons(Rect irc) {
         Rect r;
+        _indicator.visibility = Visibility.Visible;
         if (_orientation == Orientation.Vertical) {
             _indicator.layout(irc);
             if (_scrollArea.top < irc.top) {

src/dlangui/widgets/lists.d

@@ -0,0 +1,205 @@
+module dlangui.widgets.lists;
+
+import dlangui.widgets.widget;
+import dlangui.widgets.controls;
+
+/// list widget adapter provides items for list widgets
+interface ListAdapter {
+    /// returns number of widgets in list
+    @property int itemCount();
+    /// return list item widget by item index
+    Widget itemWidget(int index);
+}
+
+class ListWidget : WidgetGroup {
+    protected Orientation _orientation = Orientation.Vertical;
+    /// returns linear layout orientation (Vertical, Horizontal)
+    @property Orientation orientation() { return _orientation; }
+    /// sets linear layout orientation
+    @property LinearLayout orientation(Orientation value) { 
+        _orientation = value;
+        _scrollbar.orientation = value;
+        requestLayout(); 
+        return this; 
+    }
+
+    protected Rect[] _itemRects;
+    protected ScrollBar _scrollbar;
+
+    protected ListAdapter _adapter;
+    /// get adapter
+    @property ListAdapter adapter() { return _adapter; }
+    /// set adapter
+    @property ListWidget adapter(ListAdapter adapter) { 
+        _adapter = adapter; 
+        onAdapterChanged();
+        return this; 
+    }
+
+    /// returns number of widgets in list
+    @property int itemCount() {
+        if (_adapter !is null)
+            return _adapter.itemCount;
+        return 0;
+    }
+
+    /// return list item widget by item index
+    Widget itemWidget(int index) {
+        if (_adapter !is null)
+            return _adapter.itemWidget(index);
+        return null;
+    }
+
+    void onAdapterChanged() {
+        requestLayout();
+    }
+
+	this(string ID = null, Orientation orientation = Orientation.Vertical) {
+		super(ID);
+        _orientation = orientation;
+        _scrollbar = new ScrollBar("listscroll", orientation);
+        _scrollbar.visibility = Visibility.Gone;
+	}
+
+    /// Measure widget according to desired width and height constraints. (Step 1 of two phase layout).
+    override void measure(int parentWidth, int parentHeight) {
+        if (visibility == Visibility.Gone) {
+            _measuredWidth = _measuredHeight = 0;
+            return;
+        }
+        Rect m = margins;
+        Rect p = padding;
+        // calc size constraints for children
+        int pwidth = parentWidth;
+        int pheight = parentHeight;
+        if (parentWidth != SIZE_UNSPECIFIED)
+            pwidth -= m.left + m.right + p.left + p.right;
+        if (parentHeight != SIZE_UNSPECIFIED)
+            pheight -= m.top + m.bottom + p.top + p.bottom;
+        _scrollbar.measure(pwidth, pheight);
+        int sbsize = _orientation == Orientation.Vertical ? _scrollbar.measuredWidth : _scrollbar.measuredHeight;
+        // measure children
+		Point sz;
+        Point sbsz;
+        for (int i = 0; i < itemCount; i++) {
+            Widget w = itemWidget(i);
+            if (w is null || w.visibility == Visibility.Gone)
+                continue;
+            w.measure(pwidth, pheight);
+            if (_orientation == Orientation.Vertical) {
+                // Vertical
+                if (sz.x < w.measuredWidth)
+                    sz.x = w.measuredWidth;
+                sz.y += w.measuredHeight;
+            } else {
+                // Horizontal
+                w.measure(pwidth, pheight);
+                if (sz.y < w.measuredHeight)
+                    sz.y = w.measuredHeight;
+                sz.x += w.measuredWidth;
+            }
+        }
+        bool needScrollbar;
+        if (_orientation == Orientation.Vertical) {
+            if (pheight != SIZE_UNSPECIFIED && sz.y > pheight) {
+                // need scrollbar
+                if (pwidth != SIZE_UNSPECIFIED) {
+                    pwidth -= sbsize;
+                    sbsz.x = sbsize;
+                    needScrollbar = true;
+                }
+            }
+        } else {
+            if (pwidth != SIZE_UNSPECIFIED && sz.x > pwidth) {
+                // need scrollbar
+                if (pheight != SIZE_UNSPECIFIED) {
+                    pheight -= sbsize;
+                    sbsz.y = sbsize;
+                    needScrollbar = true;
+                }
+            }
+        }
+        if (needScrollbar) {
+            // recalculate with scrollbar
+            sz.x = sz.y = 0;
+            for (int i = 0; i < itemCount; i++) {
+                Widget w = itemWidget(i);
+                if (w is null || w.visibility == Visibility.Gone)
+                    continue;
+                w.measure(pwidth, pheight);
+                if (_orientation == Orientation.Vertical) {
+                    // Vertical
+                    if (sz.x < w.measuredWidth)
+                        sz.x = w.measuredWidth;
+                    sz.y += w.measuredHeight;
+                } else {
+                    // Horizontal
+                    w.measure(pwidth, pheight);
+                    if (sz.y < w.measuredHeight)
+                        sz.y = w.measuredHeight;
+                    sz.x += w.measuredWidth;
+                }
+            }
+        }
+        measuredContent(parentWidth, parentHeight, sz.x + sbsz.x, sz.y + sbsz.y);
+    }
+
+    /// Set widget rectangle to specified value and layout widget contents. (Step 2 of two phase layout).
+    override void layout(Rect rc) {
+        if (visibility == Visibility.Gone) {
+            return;
+        }
+        _pos = rc;
+        applyMargins(rc);
+        applyPadding(rc);
+
+        if (_itemRects.length < itemCount)
+            _itemRects.length = itemCount;
+
+        Rect r;
+		Point sz;
+        Point sbsz;
+        int sbsize = _orientation == Orientation.Vertical ? _scrollbar.measuredWidth : _scrollbar.measuredHeight;
+        r = rc;
+        for (int i = 0; i < itemCount; i++) {
+
+            Widget w = itemWidget(i);
+            if (w is null || w.visibility == Visibility.Gone)
+                continue;
+            if (_orientation == Orientation.Vertical) {
+                w.measure(rc.width, SIZE_UNSPECIFIED);
+                // Vertical
+                if (sz.x < w.measuredWidth)
+                    sz.x = w.measuredWidth;
+                sz.y += w.measuredHeight;
+                r.bottom =
+            } else {
+                // Horizontal
+                w.measure(pwidth, pheight);
+                if (sz.y < w.measuredHeight)
+                    sz.y = w.measuredHeight;
+                sz.x += w.measuredWidth;
+            }
+        }
+
+        _needLayout = false;
+    }
+    /// Draw widget at its position to buffer
+    override void onDraw(DrawBuf buf) {
+        if (visibility != Visibility.Visible)
+            return;
+        super.onDraw(buf);
+        Rect rc = _pos;
+        applyMargins(rc);
+        applyPadding(rc);
+        ClipRectSaver(buf, rc);
+		for (int i = 0; i < _children.count; i++) {
+			Widget item = _children.get(i);
+			if (item.visibility != Visibility.Visible)
+				continue;
+			item.onDraw(buf);
+		}
+    }
+
+}
+