FileDialog - move to file in list by typing first letters of its name - fix #312

src/dlangui/dialogs/filedlg.d

@@ -212,6 +212,39 @@ class FileDialog : Dialog, CustomGridCellAdapter {
         return openDirectory(_path, null);
     }
 
+    protected void locateFileInList(dstring pattern) {
+        if (!pattern.length)
+            return;
+        int selection = _fileList.row;
+        if (selection < 0)
+            selection = 0;
+        int index = -1; // first matched item
+        string mask = pattern.toUTF8;
+        // search forward from current row to end of list
+        for(int i = selection; i < _entries.length; i++) {
+            string fname = baseName(_entries[i].name);
+            if (fname.startsWith(mask)) {
+                index = i;
+                break;
+            }
+        }
+        if (index < 0) {
+            // search from beginning of list to current position
+            for(int i = 0; i < selection && i < _entries.length; i++) {
+                string fname = baseName(_entries[i].name);
+                if (fname.startsWith(mask)) {
+                    index = i;
+                    break;
+                }
+            }
+        }
+        if (index >= 0) {
+            // move selection
+            _fileList.selectCell(1, index + 1);
+            window.update();
+        }
+    }
+
     protected bool openDirectory(string dir, string selectedItemPath) {
         dir = buildNormalizedPath(dir);
         Log.d("FileDialog.openDirectory(", dir, ")");
@@ -502,6 +535,12 @@ class FileDialog : Dialog, CustomGridCellAdapter {
         _fileList.cellPopupMenu = &getCellPopupMenu;
         _fileList.menuItemAction = &handleAction;
 
+        _fileList.keyEvent = delegate(Widget source, KeyEvent event) {
+            if (_shortcutHelper.onKeyEvent(event))
+                locateFileInList(_shortcutHelper.text);
+            return false;
+        };
+
         rightPanel.addChild(_edPath);
         rightPanel.addChild(_fileList);
         rightPanel.addChild(fnlayout);
@@ -530,6 +569,8 @@ class FileDialog : Dialog, CustomGridCellAdapter {
 
     }
 
+    protected TextTypingShortcutHelper _shortcutHelper;
+
     /// Set widget rectangle to specified value and layout widget contents. (Step 2 of two phase layout).
     override void layout(Rect rc) {
         super.layout(rc);

src/dlangui/widgets/widget.d

@@ -1792,6 +1792,57 @@ class WidgetGroupDefaultDrawing : WidgetGroup {
     }
 }
 
+/// helper for locating items in list, tree, table or other controls by typing their name
+struct TextTypingShortcutHelper {
+    int timeoutMillis = 800; // expiration time for entered text; after timeout collected text will be cleared
+    private long _lastUpdateTimeStamp;
+    private dchar[] _text;
+    /// cancel text collection (next typed text will be collected from scratch)
+    void cancel() {
+        _text.length = 0;
+        _lastUpdateTimeStamp = 0;
+    }
+    /// returns collected text string - use it for lookup
+    @property dstring text() { return _text.dup; }
+    /// pass key event here; returns true if search text is updated and you can move selection using it
+    bool onKeyEvent(KeyEvent event) {
+        long ts = currentTimeMillis;
+        if (_lastUpdateTimeStamp && ts - _lastUpdateTimeStamp > timeoutMillis)
+            cancel();
+        if (event.action == KeyAction.Text) {
+            _text ~= event.text;
+            _lastUpdateTimeStamp = ts;
+            return _text.length > 0;
+        }
+        if (event.action == KeyAction.KeyDown || event.action == KeyAction.KeyUp) {
+            switch (event.keyCode) with (KeyCode) {
+                case LEFT:
+                case RIGHT:
+                case UP:
+                case DOWN:
+                case HOME:
+                case END:
+                case TAB:
+                case PAGEUP:
+                case PAGEDOWN:
+                case BACK:
+                    cancel();
+                    break;
+                default:
+                    break;
+            }
+        }
+        return false;
+    }
+
+    /// cancel text typing on some mouse events, if necessary
+    void onMouseEvent(MouseEvent event) {
+        if (event.action == MouseAction.ButtonUp || event.action == MouseAction.ButtonDown)
+            cancel();
+    }
+}
+
+
 enum ONE_SECOND = 10_000_000L;
 
 /// Helper to handle animation progress