我的应用依赖于在后台与外部硬件保持同步的 Service。因为该服务在 main 线程上运行，所以它使用 IntentService 异步执行任何繁重的工作。这是解释控制流的代码的最小化示例:

public class MyService extends Service {
  private final Handler handler = new Handler();

  void someMethodDoesCallBarAsynchronously(){
    Intent i = new Intent(this, MyIntentService.class);
    i.putAction(ACTION_FOO);
    i.putExtra(EXTRA_RECEIVER, new MyResultReceiver(handler));
    startService(toGetScannerStatus);
  }

  void receivedFooResult(String bar){
    //...
  }

  public class MyResultReceiver extends ResultReceiver{

    public MyResultReceiver(Handler handler){
      super(handler);
    }

    @Override
    protected void onReceiveResult(int resultCode, Bundle resultData) {
      super.onReceiveResult(resultCode, resultData);

      switch(resultCode){
        case RESULT_CODE_FOO:
          receivedFooResult(resultData.getString(FOO_RESULT));
        break;
      }
    }
  }
}

public class MyIntentService extends IntentService {

  public MyIntentService(){super("MyIntentService");}

  @Override
  protected void onHandleIntent(Intent intent) {
    switch (intent.getAction()) {
      case ACTION_FOO:
        ResultReceiver receiver = intent.getParcelableExtra(EXTRA_RECEIVER);
        Bundle bundle = new Bundle()
        bundle.putString(FOO_RESULT, foo());
        receiver.send(RESULT_CODE_FOO, b);
      break;
  }
}

现在，经过半年和一些更新，Android Studio 提示 MyResultReceiver 实现了 Parcelable 但没有提供 CREATOR 字段。问题一，MyResultReceiver 是一个内部类，所以我必须把它放到一个自己的类中。我无法将其设为 static，因为它必须包含对 MyService 的引用。这仍然很容易:

public class MyService extends Service {
  private final Handler handler = new Handler();

  void someMethodDoesCallBarAsynchronously(){
    Intent i = new Intent(this, MyIntentService.class);
    i.putAction(ACTION_FOO);
    i.putExtra(EXTRA_RECEIVER, new MyResultReceiver(this, handler));
    startService(toGetScannerStatus);
  }

  void receivedFooResult(String bar){
    //...
  }
}

public class MyResultReceiver extends ResultReceiver{
  private final MyService myService;

  public MyResultReceiver(MyService s, Handler handler){
    super(handler);
    this.myService = myService;
  }

  @Override
  protected void onReceiveResult(int resultCode, Bundle resultData) {
    super.onReceiveResult(resultCode, resultData);

    switch(resultCode){
      case RESULT_CODE_FOO:
        myService.receivedFooResult(resultData.getString(FOO_RESULT));
      break;
    }
  }
}

现在我可以添加一个公共(public)静态字段。但是如何正确实现CREATOR？

public class MyResultReceiver extends ResultReceiver {

  public static final Parcelable.Creator<MyResultReceiver> CREATOR
    = new Parcelable.Creator<MyResultReceiver>() {
        public MyResultReceiver[] newArray(int size) {
          return new MyResultReceiver[size];
        }
        public MyResultReceiver createFromParcel(Parcel in) {
          // ???
        }
      };

如果您想:为什么需要这样做？它将用于什么？

最佳答案

恕我直言，您当前的架构太复杂了:您可以在一个 Service 中轻松做到这一点，但当涉及到您的问题时，这取决于您:您不需要创建任何 CREATOR 因为你得到的是一个 lint 警告，只需像这样添加 SuppressLint 注释:

@SuppressLint("ParcelCreator")
public class MyResultReceiver extends ResultReceiver {

关于Android Service为IntentService扩展ResultReceiver，CREATOR如何实现？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33889229/