corrected overlay positions

2021-09-06 16:46:15 +05:30
parent 0a384f3c45
commit ae2e8b740f
2 changed files with 112 additions and 109 deletions
@@ -0,0 +1,145 @@
+import 'package:flutter/material.dart';
+
+class AnchoredOverlay extends StatelessWidget {
+  final bool showOverlay;
+  final Widget Function(BuildContext, Offset anchor) overlayBuilder;
+  final Widget child;
+
+  AnchoredOverlay({
+    this.showOverlay = false,
+    required this.overlayBuilder,
+    required this.child,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return new Container(
+      child: new LayoutBuilder(
+          builder: (BuildContext context, BoxConstraints constraints) {
+        return new OverlayBuilder(
+          showOverlay: showOverlay,
+          overlayBuilder: (BuildContext overlayContext) {
+            RenderBox box = context.findRenderObject() as RenderBox;
+            final center =
+                box.size.center(box.localToGlobal(const Offset(0.0, 0.0)));
+            return overlayBuilder(overlayContext, center);
+          },
+          child: child,
+        );
+      }),
+    );
+  }
+}
+
+class OverlayBuilder extends StatefulWidget {
+  final bool showOverlay;
+  final Widget Function(BuildContext) overlayBuilder;
+  final Widget child;
+
+  OverlayBuilder({
+    this.showOverlay = false,
+    required this.overlayBuilder,
+    required this.child,
+  });
+
+  @override
+  _OverlayBuilderState createState() => new _OverlayBuilderState();
+}
+
+class _OverlayBuilderState extends State<OverlayBuilder> {
+  OverlayEntry? overlayEntry;
+
+  @override
+  void initState() {
+    super.initState();
+
+    if (widget.showOverlay) {
+      WidgetsBinding.instance?.addPostFrameCallback((_) => showOverlay());
+    }
+  }
+
+  @override
+  void didUpdateWidget(OverlayBuilder oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    WidgetsBinding.instance
+        ?.addPostFrameCallback((_) => syncWidgetAndOverlay());
+  }
+
+  @override
+  void reassemble() {
+    super.reassemble();
+    WidgetsBinding.instance
+        ?.addPostFrameCallback((_) => syncWidgetAndOverlay());
+  }
+
+  @override
+  void dispose() {
+    if (isShowingOverlay()) {
+      hideOverlay();
+    }
+
+    super.dispose();
+  }
+
+  bool isShowingOverlay() => overlayEntry != null;
+
+  void showOverlay() {
+    overlayEntry = OverlayEntry(
+      builder: widget.overlayBuilder,
+    );
+    if (overlayEntry != null) {
+      addToOverlay(overlayEntry!);
+    }
+  }
+
+  void addToOverlay(OverlayEntry entry) async {
+    print('addToOverlay');
+    Overlay.of(context)?.insert(entry);
+  }
+
+  void hideOverlay() {
+    print('hideOverlay');
+    overlayEntry?.remove();
+    overlayEntry = null;
+  }
+
+  void syncWidgetAndOverlay() {
+    if (isShowingOverlay() && !widget.showOverlay) {
+      hideOverlay();
+    } else if (!isShowingOverlay() && widget.showOverlay) {
+      showOverlay();
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return widget.child;
+  }
+}
+
+class CenterAbout extends StatelessWidget {
+  final Offset position;
+  final Widget child;
+
+  CenterAbout({
+    required this.position,
+    required this.child,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    var size = MediaQuery.of(context).size;
+
+    return Positioned(
+      bottom: size.height - position.dy,
+      left: position.dx,
+      child: FractionalTranslation(
+        translation: const Offset(-0.5, 0.0),
+        child: Padding(
+          padding: const EdgeInsets.only(bottom: 32.0),
+          child: child,
+        ),
+      ),
+    );
+  }
+}