flame/doc/examples/with_widgets_overlay/lib/example_game.dart

import 'package:flame/game.dart';
import 'package:flame/gestures.dart';
import 'package:flame/palette.dart';

import 'package:flutter/material.dart';

class ExampleGame extends Game with HasWidgetsOverlay, TapDetector {
  bool isPaused = false;

  @override
  void update(double dt) {}

  @override
  void render(Canvas canvas) {
    canvas.drawRect(const Rect.fromLTWH(100, 100, 100, 100),
        Paint()..color = BasicPalette.white.color);
  }

  @override
  void onTap() {
    if (isPaused) {
      removeWidgetOverlay('PauseMenu');
      isPaused = false;
    } else {
      addWidgetOverlay(
          'PauseMenu',
          Center(
            child: Container(
              width: 100,
              height: 100,
              color: const Color(0xFFFF0000),
              child: const Center(child: const Text('Paused')),
            ),
          ));
      isPaused = true;
    }
  }
}