flutter在windows环境运行ios真机 flutter支持android版本

• dispose：释放此View时调用，此方法调用后 View 不可用，此方法需要清除所有对象引用，否则会造成内存泄漏。

class MyFlutterView(context: Context) : PlatformView {
override fun getView(): View {
TODO(“Not yet implemented”)
}
override fun dispose() {
TODO(“Not yet implemented”)
}
}

2.3 设置返回的View为TextView

class MyFlutterView(context: Context, messenger: BinaryMessenger, viewId: Int, args: Map<String, Any>?) : PlatformView {
val textView: TextView = TextView(context)
init {
textView.text = “我是Android View”
}
override fun getView(): View {
return textView
}
override fun dispose() {
TODO(“Not yet implemented”)
}
}

说明：

• messenger：用于消息传递，后面介绍 Flutter 与 原生通信时用到此参数
• viewId：View 生成时会分配一个唯一 ID
• args：Flutter 传递的初始化参数

2.4 注册PlatformView

创建PlatformViewFactory

class MyFlutterViewFactory(val messenger: BinaryMessenger) : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
override fun create(context: Context, viewId: Int, args: Any?): PlatformView {
val flutterView = MyFlutterView(context, messenger, viewId, args as Map<String, Any>?)
return flutterView
}
}

创建MyPlugin

class MyPlugin : FlutterPlugin {
override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
val messenger: BinaryMessenger = binding.binaryMessenger
binding
.platformViewRegistry
.registerViewFactory(
“plugins.flutter.io/custom_platform_view”, MyFlutterViewFactory(messenger))
}
companion object {
@JvmStatic
fun registerWith(registrar: PluginRegistry.Registrar) {
registrar
.platformViewRegistry()
.registerViewFactory(
“plugins.flutter.io/custom_platform_view”,
MyFlutterViewFactory(registrar.messenger()))
}
}
override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
}
}

说明：

• plugins.flutter.io/custom_platform_view ，这个字符串在 Flutter 中需要与其保持一致

2.5 在 App 中 MainActivity 中注册

class MainActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
flutterEngine.plugins.add(MyPlugin())
}
}

2.6 嵌入Flutter

void main() => runApp(PlatformViewDemo());
class PlatformViewDemo extends StatelessWidget {
@override
Widget build(BuildContext context) {
Widget? platformView(){
if(defaultTargetPlatform == TargetPlatform.android){
return AndroidView(
viewType: ‘plugins.flutter.io/custom_platform_view’
);
}
}
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: Text(“Flutter Demo”),),
body: Center(
child: platformView(),
),
),
);
}
}

2.7 效果图

三 设置初始化参数

---

3.1 Flutter 端修改如下

AndroidView(
viewType: ‘plugins.flutter.io/custom_platform_view’,
creationParams: {‘text’: ‘Flutter传给AndroidTextView的参数’},
creationParamsCodec: StandardMessageCodec(),
)

说明：

• creationParams ：传递的参数，插件可以将此参数传递给 AndroidView 的构造函数
• creationParamsCodec ：将 creationParams 编码后再发送给平台侧，它应该与传递给构造函数的编解码器匹配。值的范围：
• StandardMessageCodec
• JSONMessageCodec
• StringCodec
• BinaryCodec

3.2 修改 MyFlutterView

class MyFlutterView(context: Context, messenger: BinaryMessenger, viewId: Int, args: Map<String, Any>?) : PlatformView {
val textView: TextView = TextView(context)
init {
args?.also {
textView.text = it[“text”] as String
}
}
override fun getView(): View {
return textView
}
override fun dispose() {
TODO(“Not yet implemented”)
}
}

说明：

• it[“text”]为Flutter端参数text，获取到的值为Flutter传给AndroidTextView的参数

3.3 效果图

四 Flutter 向 Android View 发送消息

---

4.1 修改 Flutter 端，创建 MethodChannel 用于通信

void main() => runApp(PlatformViewDemo());
class PlatformViewDemo extends StatefulWidget {
@override
State createState() => _PlatformViewDemoState();
}
class _PlatformViewDemoState extends State {
static const platform = const MethodChannel(‘com.example.androidflutter.MyFlutterView’);
@override
Widget build(BuildContext context) {
Widget? platformView() {
if (defaultTargetPlatform == TargetPlatform.android) {
return AndroidView(
viewType: ‘plugins.flutter.io/custom_platform_view’,
creationParams: {‘text’: ‘Flutter传给AndroidTextView的参数’},
creationParamsCodec: StandardMessageCodec(),
);
}
}
return MaterialApp(
home: Scaffold(
appBar: AppBar(title: Text(“Flutter”),),
body: Column(children: [
RaisedButton(
child: Text(‘传递参数给原生View’),
onPressed: () {
platform.invokeMethod(‘setText’, {‘name’: ‘张三’, ‘age’: 18});
},
),
Expanded(child: Center(child: platformView(),)),
]),
),
);
}
}

说明：

• MethodChannel(‘com.example.androidflutter.MyFlutterView’)：为原生端MyFlutterView的全路径

4.2 原生View 中也创建一个 MethodChannel 用于通信

class MyFlutterView(context: Context, messenger: BinaryMessenger, viewId: Int, args: Map<String, Any>?):PlatformView, MethodChannel.MethodCallHandler {
val textView: TextView = TextView(context)
private lateinit var methodChannel: MethodChannel
init {
args?.also {
textView.text = it[“text”] as String
methodChannel = MethodChannel(messenger, “com.example.androidflutter.MyFlutterView”)
methodChannel.setMethodCallHandler(this)
}
}