如何在颤动中绘制其他应用程序？

Question

我想即使我的 Flutter 应用关闭也显示警告框或弹出。和这张图差不多

Answer 1

你可以查看这个插件system_alert_window

一个 Flutter 插件，用于在所有其他应用程序以及回调事件上显示 Truecaller 之类的叠加窗口。

Answer 2

将此添加到您的 pubspec 文件中

dependencies:
  system_alert_window: ^0.3.2+1

运行

flutter pub get

导入你的飞镖代码

import 'package:system_alert_window/system_alert_window.dart';

示例代码取自here

import 'package:flutter/material.dart';
import 'dart:async';

import 'package:flutter/services.dart';
import 'package:system_alert_window/system_alert_window.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _platformVersion = 'Unknown';
  bool _isShowingWindow = false;
  bool _isUpdatedWindow = false;

  @override
  void initState() {
    super.initState();
    _initPlatformState();
    _checkPermissions();
    SystemAlertWindow.registerOnClickListener(callBack);
  }

  // Platform messages are asynchronous, so we initialize in an async method.
  Future<void> _initPlatformState() async {
    String platformVersion;
    // Platform messages may fail, so we use a try/catch PlatformException.
    try {
      platformVersion = await SystemAlertWindow.platformVersion;
    } on PlatformException {
      platformVersion = 'Failed to get platform version.';
    }

    // If the widget was removed from the tree while the asynchronous platform
    // message was in flight, we want to discard the reply rather than calling
    // setState to update our non-existent appearance.
    if (!mounted) return;

    setState(() {
      _platformVersion = platformVersion;
    });
  }

  Future<void> _checkPermissions() async {
    await SystemAlertWindow.checkPermissions;
  }

  void _showOverlayWindow() {
    if (!_isShowingWindow) {
      SystemWindowHeader header = SystemWindowHeader(
          title: SystemWindowText(text: "Incoming Call", fontSize: 10, textColor: Colors.black45),
          padding: SystemWindowPadding.setSymmetricPadding(12, 12),
          subTitle: SystemWindowText(text: "9898989899", fontSize: 14, fontWeight: FontWeight.BOLD, textColor: Colors.black87),
          decoration: SystemWindowDecoration(startColor: Colors.grey[100]),
          button: SystemWindowButton(text: SystemWindowText(text: "Personal", fontSize: 10, textColor: Colors.black45), tag: "personal_btn"),
          buttonPosition: ButtonPosition.TRAILING);
      SystemWindowBody body = SystemWindowBody(
        rows: [
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Some body", fontSize: 12, textColor: Colors.black45),
              ),
            ],
            gravity: ContentGravity.CENTER,
          ),
          EachRow(columns: [
            EachColumn(
                text: SystemWindowText(text: "Long data of the body", fontSize: 12, textColor: Colors.black87, fontWeight: FontWeight.BOLD),
                padding: SystemWindowPadding.setSymmetricPadding(6, 8),
                decoration: SystemWindowDecoration(startColor: Colors.black12, borderRadius: 25.0),
                margin: SystemWindowMargin(top: 4)),
          ], gravity: ContentGravity.CENTER),
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Notes", fontSize: 10, textColor: Colors.black45),
              ),
            ],
            gravity: ContentGravity.LEFT,
            margin: SystemWindowMargin(top: 8),
          ),
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Some random notes.", fontSize: 13, textColor: Colors.black54, fontWeight: FontWeight.BOLD),
              ),
            ],
            gravity: ContentGravity.LEFT,
          ),
        ],
        padding: SystemWindowPadding(left: 16, right: 16, bottom: 12, top: 12),
      );
      SystemWindowFooter footer = SystemWindowFooter(
          buttons: [
            SystemWindowButton(
              text: SystemWindowText(text: "Simple button", fontSize: 12, textColor: Color.fromRGBO(250, 139, 97, 1)),
              tag: "simple_button",
              padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
              width: 0,
              height: SystemWindowButton.WRAP_CONTENT,
              decoration: SystemWindowDecoration(startColor: Colors.white, endColor: Colors.white, borderWidth: 0, borderRadius: 0.0),
            ),
            SystemWindowButton(
              text: SystemWindowText(text: "Focus button", fontSize: 12, textColor: Colors.white),
              tag: "focus_button",
              width: 0,
              padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
              height: SystemWindowButton.WRAP_CONTENT,
              decoration: SystemWindowDecoration(
                  startColor: Color.fromRGBO(250, 139, 97, 1), endColor: Color.fromRGBO(247, 28, 88, 1), borderWidth: 0, borderRadius: 30.0),
            )
          ],
          padding: SystemWindowPadding(left: 16, right: 16, bottom: 12),
          decoration: SystemWindowDecoration(startColor: Colors.white),
          buttonsPosition: ButtonPosition.CENTER);
      SystemAlertWindow.showSystemWindow(
          height: 230,
          header: header,
          body: body,
          footer: footer,
          margin: SystemWindowMargin(left: 8, right: 8, top: 200, bottom: 0),
          gravity: SystemWindowGravity.TOP);
      setState(() {
        _isShowingWindow = true;
      });
    } else if (!_isUpdatedWindow) {
      SystemWindowHeader header = SystemWindowHeader(
          title: SystemWindowText(text: "Outgoing Call", fontSize: 10, textColor: Colors.black45),
          padding: SystemWindowPadding.setSymmetricPadding(12, 12),
          subTitle: SystemWindowText(text: "8989898989", fontSize: 14, fontWeight: FontWeight.BOLD, textColor: Colors.black87),
          decoration: SystemWindowDecoration(startColor: Colors.grey[100]),
          button: SystemWindowButton(text: SystemWindowText(text: "Personal", fontSize: 10, textColor: Colors.black45), tag: "personal_btn"),
          buttonPosition: ButtonPosition.TRAILING);
      SystemWindowBody body = SystemWindowBody(
        rows: [
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Updated body", fontSize: 12, textColor: Colors.black45),
              ),
            ],
            gravity: ContentGravity.CENTER,
          ),
          EachRow(columns: [
            EachColumn(
                text: SystemWindowText(text: "Updated long data of the body", fontSize: 12, textColor: Colors.black87, fontWeight: FontWeight.BOLD),
                padding: SystemWindowPadding.setSymmetricPadding(6, 8),
                decoration: SystemWindowDecoration(startColor: Colors.black12, borderRadius: 25.0),
                margin: SystemWindowMargin(top: 4)),
          ], gravity: ContentGravity.CENTER),
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Notes", fontSize: 10, textColor: Colors.black45),
              ),
            ],
            gravity: ContentGravity.LEFT,
            margin: SystemWindowMargin(top: 8),
          ),
          EachRow(
            columns: [
              EachColumn(
                text: SystemWindowText(text: "Updated random notes.", fontSize: 13, textColor: Colors.black54, fontWeight: FontWeight.BOLD),
              ),
            ],
            gravity: ContentGravity.LEFT,
          ),
        ],
        padding: SystemWindowPadding(left: 16, right: 16, bottom: 12, top: 12),
      );
      SystemWindowFooter footer = SystemWindowFooter(
          buttons: [
            SystemWindowButton(
              text: SystemWindowText(text: "Updated Simple button", fontSize: 12, textColor: Color.fromRGBO(250, 139, 97, 1)),
              tag: "updated_simple_button",
              padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
              width: 0,
              height: SystemWindowButton.WRAP_CONTENT,
              decoration: SystemWindowDecoration(startColor: Colors.white, endColor: Colors.white, borderWidth: 0, borderRadius: 0.0),
            ),
            SystemWindowButton(
              text: SystemWindowText(text: "Focus button", fontSize: 12, textColor: Colors.white),
              tag: "focus_button",
              width: 0,
              padding: SystemWindowPadding(left: 10, right: 10, bottom: 10, top: 10),
              height: SystemWindowButton.WRAP_CONTENT,
              decoration: SystemWindowDecoration(
                  startColor: Color.fromRGBO(250, 139, 97, 1), endColor: Color.fromRGBO(247, 28, 88, 1), borderWidth: 0, borderRadius: 30.0),
            )
          ],
          padding: SystemWindowPadding(left: 16, right: 16, bottom: 12),
          decoration: SystemWindowDecoration(startColor: Colors.white),
          buttonsPosition: ButtonPosition.CENTER);
      SystemAlertWindow.updateSystemWindow(
          height: 230,
          header: header,
          body: body,
          footer: footer,
          margin: SystemWindowMargin(left: 8, right: 8, top: 200, bottom: 0),
          gravity: SystemWindowGravity.TOP);
      setState(() {
        _isUpdatedWindow = true;
      });
    } else {
      setState(() {
        _isShowingWindow = false;
        _isUpdatedWindow = false;
      });
      SystemAlertWindow.closeSystemWindow();
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('System Alert Window Example App'),
        ),
        body: Center(
          child: Column(
            children: <Widget>[
              Text('Running on: $_platformVersion\n'),
              Padding(
                padding: const EdgeInsets.symmetric(vertical: 8.0),
                child: MaterialButton(
                  onPressed: _showOverlayWindow,
                  textColor: Colors.white,
                  child: !_isShowingWindow
                      ? Text("Show system alert window")
                      : !_isUpdatedWindow ? Text("Update system alert window") : Text("Close system alert window"),
                  color: Colors.deepOrange,
                  padding: const EdgeInsets.symmetric(vertical: 8.0),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

///
/// Whenever a button is clicked, this method will be invoked with a tag (As tag is unique for every button, it helps in identifying the button).
/// You can check for the tag value and perform the relevant action for the button click
///
void callBack(String tag) {
  print(tag);
  switch (tag) {
    case "simple_button":
    case "updated_simple_button":
      SystemAlertWindow.closeSystemWindow();
      break;
    case "focus_button":
      print("Focus button has been called");
      break;
    default:
      print("OnClick event of $tag");
  }
}