flutter添加水印、添加自定义水印、禁止截屏(Android)
一、前言
现实生活中，我们想要对应用的开发程序内容进行管控，避免暴露出敏感信息。因此，在很多的pc端的开发页面上，经常能看见水印，这种水印的实现，在html、vue等技术上对于开发过的人来说十分的简单。当然，App端同样也有很多的敏感信息，避免暴露出去因此需要加上水印。
自己这次的开发需求上就遇见了，因为是第一次接触flutter，对与很多东西都不懂更别说全局设置什么水印了，所以，在网上查询了好久，诸如“flutter 添加水印”、“fluter设置水印”…查询出来的博客、页面，屁都不是，满屏幕的什么涂鸦的方法乱七八糟，所以自己从pub.dev上面找出来的demo，仔细调试了调试，贴出源码，为各位提供参考，实现效果如下：
实现代码如下：
import 'dart:math';
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:disable_screenshots/disable_screenshots.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State {
@override
Widget build(BuildContext context) {
return MaterialApp(home: RootApp());
}
}
class RootApp extends StatefulWidget {
@override
_RootAppState createState() => _RootAppState();
}
class _RootAppState extends State {
// 初始化插件
DisableScreenshots _plugin = DisableScreenshots();
// 监控截屏行为的stream
StreamSubscription _screenshotsSubscription;
int _screenshotsCount = 0;
bool _disableScreenshots = false;
@override
void initState() {
super.initState();
_screenshotsSubscription = _plugin.onScreenShots.listen((event) {
setState(() {
_screenshotsCount++;
});
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('冷月寒雪'),
),
body: Column(
children: [
Center(
child: Text("监控到截屏次数：$_screenshotsCount"),
),
Center(
child: Text(_disableScreenshots ? "禁止截屏状态" : "允许截屏状态"),
),
RaisedButton(
onPressed: () {
// 添加默认样式的水印
_plugin.addWatermark(context, "默认水印",
rowCount: 4, columnCount: 8);
},
child: Text("添加默认水印")),
RaisedButton(
onPressed: () {
// 添加自定义widget当做水印
_plugin.addCustomWatermark(context,
Watarmark(rowCount: 3, columnCount: 10, text: "冷月韩雪"));
},
child: Text("添加自定义水印")),
RaisedButton(
onPressed: () {
// 移除水印
_plugin.removeWatermark();
},
child: Text("删除水印")),
RaisedButton(
onPressed: () async {
bool flag = !_disableScreenshots;
// 禁用或允许截屏（只支持iOS）
await _plugin.disableScreenshots(flag);
setState(() {
_disableScreenshots = flag;
});
},
child: Text(_disableScreenshots
? "允许截屏（仅android适用）"
: "禁用截屏（仅android适用)")),
RaisedButton(
onPressed: () {
Navigator.of(context).push(MaterialPageRoute(
builder: (_) => Scaffold(
appBar: AppBar(
title: Text("我是新页面"),
),
body: Center(child: Text("new page")),
)));
},
child: Text("进入新页面"))
],
),
);
}
@override
void dispose() {
super.dispose();
//取消截屏监控可以调用cancel()方法
if (_screenshotsSubscription != null) {
_screenshotsSubscription.cancel();
}
}
}
class Watarmark extends StatelessWidget {
final int rowCount;
final int columnCount;
final String text;
const Watarmark(
{Key key,
@required this.rowCount,
@required this.columnCount,
@required this.text})
: super(key: key);
@override
Widget build(BuildContext context) {
return IgnorePointer(
child: Container(
child: Column(
children: creatColumnWidgets(),
)),
);
}
List creatRowWdiges() {
List list = [];
for (var i = 0; i < rowCount; i++) {
final widget = Expanded(
child: Center(
child: Transform.rotate(
angle: pi / 10,
child: Text(
text,
style: TextStyle(
color: Color(0x08000000),
fontSize: 18,
decoration: TextDecoration.none),
),
)));
list.add(widget);
}
return list;
}
List creatColumnWidgets() {
List list = [];
for (var i = 0; i < columnCount; i++) {
final widget = Expanded(
child: Row(
children: creatRowWdiges(),
));
list.add(widget);
}
return list;
}
}
需要依赖如下：
disable_screenshots: ^0.1.0
因为考虑到每个人版本不同的问题，这个依赖有的人会下载sdk报错，所以我把该源码也放在了下面，若果依赖下不出来，就调用源码实现，在上图main方法的 import 'package:disable_screenshots/disable_screenshots.dart 替换成倒入下面的dart文件，这样就可以完成水印的添加了。
import 'dart:io';
import 'dart:math';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
class DisableScreenshots {
static DisableScreenshots _instance;
factory DisableScreenshots() {
if (_instance == null) {
final MethodChannel methodChannel = const MethodChannel(
"com.devlxx.DisableScreenshots/disableScreenshots");
final EventChannel eventChannel =
const EventChannel('com.devlxx.DisableScreenshots/observer');
_instance = DisableScreenshots.private(methodChannel, eventChannel);
}
return _instance;
}
DisableScreenshots.private(this._methodChannel, this._eventChannel);
final MethodChannel _methodChannel;
final EventChannel _eventChannel;
Stream<void> _onScreenShots;
OverlayEntry _overlayEntry;
void addWatermark(BuildContext context, String watermark,
{int rowCount = 3, int columnCount = 10, TextStyle textStyle}) async {
if (_overlayEntry != null) {
_overlayEntry.remove();
}
OverlayState overlayState = Overlay.of(context);
_overlayEntry = OverlayEntry(
builder: (context) => DisableScreenshotsWatarmark(
rowCount: rowCount,
columnCount: columnCount,
text: watermark,
textStyle: textStyle ??
const TextStyle(
color: Color(0x08000000),
fontSize: 18,
decoration: TextDecoration.none),
));
overlayState.insert(_overlayEntry);
// return await _methodChannel.invokeMethod("addWatermark", ['我是水印']);
}
void addCustomWatermark(BuildContext context, Widget widget) {
if (_overlayEntry != null) {
_overlayEntry.remove();
}
OverlayState overlayState = Overlay.of(context);
_overlayEntry = OverlayEntry(builder: (context) => widget);
overlayState.insert(_overlayEntry);
}
void removeWatermark() async {
if (_overlayEntry != null) {
_overlayEntry.remove();
_overlayEntry = null;
}
}
Stream<void> get onScreenShots {
if (_onScreenShots == null) {
_onScreenShots = _eventChannel.receiveBroadcastStream();
}
return _onScreenShots;
}
/// 只支持安卓
Future<void> disableScreenshots(bool disable) async {
if (Platform.isAndroid) {
return await _methodChannel
.invokeMethod("disableScreenshots", {"disable": disable});
} else {
print('仅Android平台支持禁用屏幕截图');
}
}
}
class DisableScreenshotsWatarmark extends StatelessWidget {
final int rowCount;
final int columnCount;
final String text;
final TextStyle textStyle;
const DisableScreenshotsWatarmark({
Key key,
@required this.rowCount,
@required this.columnCount,
@required this.text,
@required this.textStyle,
}) : super(key: key);
@override
Widget build(BuildContext context) {
return IgnorePointer(
child: Container(
child: Column(
children: creatColumnWidgets(),
)),
);
}
List<Widget> creatRowWdiges() {
List<Widget> list = [];
for (var i = 0; i < rowCount; i++) {
final widget = Expanded(
child: Center(
child: Transform.rotate(
angle: pi / 10, child: Text(text, style: textStyle))));
list.add(widget);
}
return list;
}
List<Widget> creatColumnWidgets() {
List<Widget> list = [];
for (var i = 0; i < columnCount; i++) {
final widget = Expanded(
child: Row(
children: creatRowWdiges(),
));
list.add(widget);
}
return list;
}
}
有自定义水印、默认水印的方法，同时还有安卓系统的禁止截屏功能，需要用的到的同学参考参考吧。如有疑问，欢迎留言。