java - 如何将位图从服务发送到 java、android 中的主程序？

Question

我正在我的应用程序中创建一项服务来下载图像，我不清楚如何将结果(位图)从服务发送到主要 Activity 。我可以这样做吗？或者在服务中只能将下载的图像保存在某处并仅发送无用的消息？

Answer 1

尝试从 Activity 绑定(bind)到服务，然后将 Activity 的实例传递给服务。在这种情况下，您可以将位图从服务传递到 Activity 。但是，您需要非常小心，不要引入内存泄漏

类似这样的事情:

class TestActivity extends Activity {
    private BitmapService mBitmapService;
    private final ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName componentName,
                                       IBinder iBinder) {
            BitmapService.BitmapServiceBinder mBinder = (BitmapService.BitmapServiceBinder) iBinder;
            mBitmapService = mBinder.getBitmapService();
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {
        }
    };

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        bindService(new Intent(this, XMLDownloaderService.class), mServiceConnection, BIND_AUTO_CREATE);

    }

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

您的服务方:

public class BitmapService extends BitmapService {

    public class BitmapServiceBinder extends Binder {
        public BitmapService getBitmapService() {
             return BitmapService.this;
        }
    }

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

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

     @Override
     public void onCreate() {
          super.onCreate();
           if (mBinder == null) {
               mBinder = new BitmapServiceBinder();
           }
     }
}