Android-自定义PopupWindow，flutter开发实战详解pdf

在Flutter中，自定义PopupWindow可以通过OverlayEntry来实现。以下是一个简单的自定义PopupWindow的示例代码：

import 'package:flutter/material.dart';
 
class CustomPopupWindow extends StatefulWidget {
  @override
  _CustomPopupWindowState createState() => _CustomPopupWindowState();
}
 
class _CustomPopupWindowState extends State<CustomPopupWindow> {
  OverlayEntry? _overlayEntry;
  bool _isPopupShowing = false;
 
  void _showPopup(BuildContext context) {
    if (_overlayEntry != null) return;
 
    RenderBox renderBox = context.findRenderObject() as RenderBox;
    var size = renderBox.size;
    var offset = renderBox.localToGlobal(Offset.zero);
 
    _overlayEntry = OverlayEntry(builder: (context) {
      return Positioned(
        left: offset.dx,
        top: offset.dy + size.height,
        width: size.width,
        child: Material(
          color: Colors.white,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              ListTile(
                title: Text('选项一'),
                onTap: () {
                  // 处理选项点击事件
                  _removePopup();
                },
              ),
              ListTile(
                title: Text('选项二'),
                onTap: () {
                  // 处理选项点击事件
                  _removePopup();
                },
              ),
              // 其他选项...
            ],
          ),
        ),
      );
    });
 
    Overlay.of(context).insert(_overlayEntry!);
    setState(() {
      _isPopupShowing = true;
    });
  }
 
  void _removePopup() {
    _overlayEntry?.remove();
    _overlayEntry = null;
    setState(() {
      _isPopupShowing = false;
    });
  }
 
  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        if (_isPopupShowing) {
          _removePopup();
        } else {
          _showPopup(context);
        }
      },
      child: Container(
        alignment: Alignment.center,
        color: Colors.blue,
        child: Text(
          '点击显示Popup',
          style: TextStyle(color: Colors.white),
        ),
      ),
    );
  }
}
 
void main() {
  runApp(MyApp());
}
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('自定义PopupWindow示例'),
        ),
        body: Center(
          child: CustomPopupWindow(),