当Activity被销毁时，为什么Service会破坏自我？

Question

我想从一个Activity启动一个服务，然后让它继续运行，即使活动退出/结束。然后，当我再次启动应用程序活动时，它会重新连接到现有服务。

我已经阅读了关于bindService的文档，但是每次按下后退按钮退出活动时，服务的onUnBind都会被自动调用，从而有效地终止服务。我想我必须在服务未绑定之前手动调用unbindService。

我不知道，一旦Activity被销毁，成员变量mService，mBound和tv必须在创建新Activity时重新填充，所以下面的简单代码将显示“bindService started”并不奇怪。但我认为LocalService实例中的所有成员变量都是相同的，没有变化，所以“bindService已经开始.Val =”+ mService.myval;每次重新启动一项新活动应该保持不变，不是吗？

主要信息

public class MainActivity extends AppCompatActivity
{
    LocalService mService;
    Boolean mBound = false;
    TextView tv;

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

        tv = (TextView)findViewById(R.id.textView);    
    }

    @Override
    protected void onStart()
    {
        super.onStart();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
    }

    @Override
    protected void onDestroy()
    {
        super.onDestroy();
    }

    public void onButtonStart(View v)
    {
        String str;

        // Bind to LocalService
        if (!mBound)
        {
            Intent intent = new Intent(this, LocalService.class);

            if (!bindService(intent, mConnection, Context.BIND_AUTO_CREATE))
            {
                unbindService(mConnection);
                str = "bindService failed?!";
            }
            else
            {
                str = "bindService started.";
            }
        }
        else
            str = "bindService already Started. Val = " + mService.myval;

        tv.setText(str);
    }  

    public void onButtonStop(View v)
    {
        if (mBound)
        {
            mService.stop();
            unbindService(mConnection);
            mBound = false;

            tv.setText("Stopped Service");
        }
        else
            tv.setText("Service is not running");
    }

    private ServiceConnection mConnection = new ServiceConnection()
    {
        @Override
        public void onServiceConnected(ComponentName className, IBinder service)
        {
            // We've bound to LocalService, cast the IBinder and get LocalService instance
            LocalService.LocalBinder binder = (LocalService.LocalBinder) service;
            mService = binder.getService();
            mBound = true;
        }

        @Override
        public void onServiceDisconnected(ComponentName arg0)
        {
            mBound = false;
        }
    };   
 }

本地服务

public class LocalService extends Service
{
    private final IBinder mBinder = new LocalBinder();
    private final Random mGenerator = new Random();
    public int myval = getRandomNumber();

    @Override
    public void onCreate()
    {
        super.onCreate();
    }

    // Service is being Destroyed
    @Override
    public void onDestroy()
    {
        super.onDestroy();
    }

    public int getRandomNumber()
    {
        return mGenerator.nextInt(100);
    }

    @Override
    public IBinder onBind(Intent intent)
    {
        return mBinder;
    }

    // Client is Unbinding via the unbindService() call
    @Override
    public boolean onUnbind(Intent intent)
    {
        return super.onUnbind(intent);
    }

    public class LocalBinder extends Binder
    {
        public LocalService getService()
        {
            return LocalService.this;
        }
    }   
}

Answer 1

另一答案