如何將服務對象傳遞給MyActivity？

Question

首先：我在Android編程方面做得更好

我已經使用Service創建了簡單的TCP套接字。

觸發MainActivity的按鈕時，客戶端將連接到服務器。

現在，我想使用Service的Socket對象在MainActivity創建PrintWriter對象。

我知道可以使用JSON將對象從Service傳遞到Activity 。

我通過互聯網搜索，但不知道該如何通過。

請給我簡單的代碼示例以傳遞對象。

MyService.java

public class MyService extends Service{
public static Socket clientsocket;
public static PrintWriter printer;
SendMessage sender;

@Override
public void onCreate() {
Toast.makeText(this, "Created", Toast.LENGTH_LONG).show();
super.onCreate();
}

@Override
public void onDestroy() {
Toast.makeText(this, "Stoped", Toast.LENGTH_LONG).show();
if(clientsocket!=null){
        try{
        clientsocket.close(); 
        Toast.makeText(this, "Socket Closed", Toast.LENGTH_LONG).show();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
  }

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Toast.makeText(this, "Running", Toast.LENGTH_LONG).show();
    SendMessage sender=new SendMessage();
    sender.execute();
    return super.onStartCommand(intent, flags, startId);
}

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

class SendMessage extends AsyncTask<Void, Void, Void>{

    @Override
    protected Void doInBackground(Void... params) {
        try {
            clientsocket = new Socket("192.168.237.1", 6666);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        if(clientsocket!=null){
            Toast.makeText(MyService.this, "Connected", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(MyService.this, "Lost Connection", Toast.LENGTH_LONG).show();
        }
        super.onPostExecute(result);
    }

   }}

MainActivity.java

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

}

public void start(View v){
    startService(new Intent(this,MyService.class));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
     getMenuInflater().inflate(R.menu.main, menu);
     return true;
}

class PrintMessage extends AsyncTask<Void, Void, Void>{

    @Override
    protected Void doInBackground(Void... arg0) {
        return null;
    }
}

@Override
protected void onDestroy() {
    stopService(new Intent(this,MyService.class));
    super.onDestroy();
}}

現在，我需要為MyService.java（在這種情況下如何傳遞對象Socket對象clientsocket ）和MainActivity.java（如何取回傳遞的對象ie clientsocket並使用它來創建PrintWriter對象）的代碼都清晰而完整

Answer 1

請考慮使用事件總線庫，例如greenrobot EventBus :-)當涉及到在應用程序的各個元素之間傳遞數據時，這些工作很奇怪，並且使用起來非常安全。

Answer 2

我個人將使用以下解決方案如何使用Otto事件總線將事件從服務發送到活動？ 使用Otto Event Bus，並僅發送包含數據的類的實例。

public class MainActivity extends ActionBarActivity
{

    @Override
    protected void onResume()
    {
        super.onResume();
        SingletonBus.INSTANCE.getBus().register(this);
    }

    @Override
    protected void onPause()
    {
        SingletonBus.INSTANCE.getBus().unregister(this);
        super.onPause();
    }
    ...
}

和

// you might need to change this as linked in the above link: 
// https://stackoverflow.com/questions/15431768/how-to-send-event-from-service-to-activity-with-otto-event-bus
public enum SingletonBus
{
    INSTANCE;

    private Bus bus;

    private SingletonBus()
    {
        this.bus = new Bus(ThreadEnforcer.ANY);
    }

    public Bus getBus()
    {
        return bus;
    }
}

和

public class MyEvent
{
    private Data data;

    public MyEvent(Data data)
    {
        this.data = data;
    }

    public Data getData()
    {
        return data;
    }
}

和

SingletonBus.INSTANCE.getBus().post(new MyEvent(data));