活动实例化ResultReceiver并覆盖onReceiveResult.然后,活动将Intent发送到IntentService,并将ResultReceiver包含为额外的.一旦IntentService完成处理,它就会将消息发送回ResultReceiver并在onReceiveResult中处理它.
问题是如果用户导航离开Activity,结果仍然会发送回ResultReceiver,从而导致所有类型的问题.有没有办法阻止这种行为?我已经尝试在活动的onDestroy()中停止IntentService,但结果仍然被发回.
这是一个活动示例
public class Foo extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Intent i = new Intent(this,SampleIntentService.class); i.putExtra("receiver",mReceiver); startService(i); } @Override public void onDestroy() { stopService(new Intent(this,SampleIntentService.class)); mReceiver = null; super.onDestroy(); } ResultReceiver mReceiver = new ResultReceiver(new Handler()) { @Override protected void onReceiveResult(int resultCode,Bundle resultData) { // Handle response from IntentService here } }; }
这是一个示例IntentService
public class SampleIntentService extends IntentService { public SampleIntentService() { super(SampleIntentService.class.getName()); } @Override protected void onHandleIntent(Intent intent) { ResultReceiver rec = intent.getParcelableExtra("receiver"); if (rec != null) { rec.send(200,null); } } }
解决方法
我通过创建自定义ResultReceiver解决了这个问题,如下所示.
public class SampleResultReceiver extends ResultReceiver { private Receiver mReceiver; public SampleResultReceiver(Handler handler) { super(handler); } public void setReceiver(Receiver receiver) { mReceiver = receiver; } public interface Receiver { void onReceiveResult(int resultCode,Bundle resultData); } @Override protected void onReceiveResult(int resultCode,Bundle resultData) { if (mReceiver != null) { mReceiver.onReceiveResult(resultCode,resultData); } } }
然后在我的活动中,我执行以下操作:
public class Foo extends Activity implements Receiver { private SampleResultReceiver mReceiver; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mReceiver = new SampleResultReceiver(new Handler()); mReceiver.setReceiver(this); Intent i = new Intent(this,mReceiver); startService(i); } @Override public void onDestroy() { if (mReceiver != null) { mReceiver.setReceiver(null); } super.onDestroy(); } @Override protected void onReceiveResult(int resultCode,Bundle resultData) { // Handle response from IntentService here } }
这将导致发送到您的自定义ResultReceiver的任何消息在活动被销毁后无处可能结束:)