android - 方法 channel 在 Flutter 模块中不起作用

Question

我在 flutter 开发文档中编写演示代码来显示电池电量。
但是代码不起作用，方法 channel 在调用时显示日志错误:
- 未处理的异常:MissingPluginException(在 channel samples.flutter.dev/battery 上找不到方法 getBatteryLevel 的实现)
请帮我!谢谢大家!

Answer 1

假设您在 native 应用程序中使用缓存的 flutter 引擎。
您的应用程序类应该设置 FlutterPluginCache。

class Application : MultiDexApplication() {
    lateinit var flutterEngine : FlutterEngine

    override fun onCreate() {
        super.onCreate()

        // Instantiate a FlutterEngine.
        flutterEngine = FlutterEngine(this)

        // Start executing Dart code to pre-warm the FlutterEngine.
        flutterEngine.dartExecutor.executeDartEntrypoint(
                DartExecutor.DartEntrypoint.createDefault()
        )

        // Cache the FlutterEngine to be used by FlutterActivity.
        FlutterEngineCache
                .getInstance()
                .put("flutter_engine_id", flutterEngine)
    }
}

在您的应用程序的 Activity 中，获取 flutter 引擎并设置方法调用处理程序。

 class FlutterDemoActivity : FlutterActivity() {
      private val CHANNEL = "samples.flutter.dev/battery"
      private val flutter_engine_id = "flutter_engine_id"

      @SuppressLint("SetTextI18n")
      override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_flutter_demo)
        
        //Get your flutter engine using engine id. 
        val engine = FlutterEngineCache.getInstance().get(flutter_engine_id)
        engine?.let{
          //Set method call handler to that engine.
          MethodChannel(it.dartExecutor.binaryMessenger, 
          CHANNEL).setMethodCallHandler {
             call, result ->
             if(call.method=="getBatteryLevel"){
               result.success(89) //send whatever you need here.
            }
          }
        }
      }
    }