我想让一个飞镖后台服务永远运行(隔离),它将通过 websockets 与服务器通信。我有一个适用于 Android 的 API,它收集信息以发送到服务器。如何调用使用回调的 Android 方法以及来自后台隔离的所有内容?
编辑
到目前为止,在 dart 中,我创建了一个 Isolate 以在后台定期调用 poolSong 方法,即使用户正在使用另一个应用程序或屏幕已关闭。
但这给了我下面的错误......在 github 问题上,他们说我不能从不同的 Isolate 发送平台消息,除非它是主要的。但是,如果我从主隔离中执行此操作,则当用户退出应用程序时,隔离也将终止。
主要飞镖
class _MyHomePageState extends State<MyHomePage> {
final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();
static const platform = const MethodChannel('mainService');
static _poolSong(SendPort sendPort) async {
const oneSec = const Duration(seconds:1);
new Timer.periodic(oneSec, (Timer t) => platform.invokeMethod('poolSong'));
}
@override
void initState() {
super.initState();
ReceivePort receivePort = ReceivePort();
Isolate.spawn(_poolSong, receivePort.sendPort);
}
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MainActivityJava
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GeneratedPluginRegistrant.registerWith(this);
new MethodChannel(getFlutterView(), CHANNEL).setMethodCallHandler(
(call, result) -> {
if (call.method.equals("startService"))
startService();
if (call.method.equals("poolSong"))
poolSong();
}
);
}
错误
E/flutter (25412): [ERROR:flutter/runtime/dart_isolate.cc(717)] Isolate (765499726) 'main.dart:_poolSong()' exited with an error
E/flutter (25412): [ERROR:flutter/shell/common/shell.cc(186)] Dart Error: Unhandled exception:
E/flutter (25412): error: native function 'Window_sendPlatformMessage' (4 arguments) cannot be found
E/flutter (25412): #0 Window.sendPlatformMessage (dart:ui/window.dart:811:9)
E/flutter (25412): #1 BinaryMessages._sendPlatformMessage (package:flutter/src/services/platform_messages.dart:39:15)
E/flutter (25412): #2 BinaryMessages.send (package:flutter/src/services/platform_messages.dart:87:12)
E/flutter (25412): #3 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:286:49)
E/flutter (25412): <asynchronous suspension>
E/flutter (25412): #4 _MyHomePageState._poolSong.<anonymous closure> (package:musictie/main.dart:37:54)
E/flutter (25412): #5 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:382:19)
E/flutter (25412): #6 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
E/flutter (25412): #7 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)