我有一个粘性服务（START_STICKY从中返回onStartCommand），它在 中执行一些代码AsyncTask，但是我在如何以及何时开始、绑定、停止、取消绑定方面遇到了一些问题。我只希望在父活动还活着的时候服务，我不希望它在应用程序关闭时在后台徘徊，但我需要该服务在方向变化中幸存下来。我目前不需要该服务在整个活动期间都处于活动状态，因此我在我的主要工作完成后调用 stopSelf() AsyncTask，Service然后Service在需要时再次启动。有时我需要中断服务正在进行的工作，取消AsyncTask并以不同的数据重新开始。问题是，无论我做什么——我似乎都无法在所有不同的可能情况下都做到这一点。谁能看看并告诉我我做错了什么？
我Service的是：
public class ChordCalculatorService extends Service {
private final IBinder mBinder = new LocalBinder();
private AsyncTask<SearchData, SearchStatusData, List<Item>> currentTask;
@Override
public void onCreate() {}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// We want this service to continue running until it is explicitly
// stopped, so return sticky.
return START_STICKY;
}
/**
* Class for clients to access. Because we know this service always runs in
* the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
public ChordCalculatorService getService() {
return ChordCalculatorService.this;
}
}
@Override
public void onDestroy() {
super.onDestroy();
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
public SearchData getSearchData() {
return searchData;
}
public void startWork() {
if (currentTask != null && currentTask.getStatus() == Status.RUNNING) {
currentTask.cancel(true);
}
if(searchData != null) {
Worker task = new Worker();
currentTask = task.execute(new SearchData[] { searchData });
} else {
Message msg = handler.obtainMessage(ERROR, "No search data set");
handler.sendMessage(msg);
}
}
class Worker extends AsyncTask<SearchData, SearchStatusData, List<Item>> {
// ... code ...
@Override
protected void onPostExecute(List<Item> result) {
Message msg = handler.obtainMessage(COMPLETE, new StatusData(Status.STATUS_FINISHED, result));
handler.sendMessage(msg);
stopSelf();
}
}
}
目前，Service当我的自定义创建时，我已经开始View：
public class MyCustomView extends BasicFretBoardView {
private ServiceConnection conn;
private MyService myService;
private boolean isServiceStarted;
private boolean isServiceBound;
public MyCustomView(Context context, AttributeSet attr) {
super(context, attr);
startService();
}
public void startService() {
Intent serviceIntent = new Intent(getContext(), MyService.class);
conn = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
myService = ((LocalBinder) service).getService();
myService.registerHandler(serviceHandler);
}
@Override
public void onServiceDisconnected(ComponentName name) {
myService = null;
}
};
// Explicitly start the service. Don't use BIND_AUTO_CREATE, since it
// causes an implicit service stop when the last binder is removed.
getContext().startService(serviceIntent);
getContext().bindService(serviceIntent, conn, 0);
isServiceStarted = true;
isServiceBound = true;
}
public void stopService() {
if (isServiceStarted) {
Intent serviceIntent = new Intent(getContext(), MyService.class);
getContext().stopService(serviceIntent);
isServiceStarted = false;
}
unBindService();
}
public void unBindService() {
if(isServiceBound) {
getContext().unbindService(conn);
isServiceBound = false;
}
}
// gets called based on some user interaction
private void startServiceWork() {
if(!isServiceStarted) {
startService();
} else {
myService.cancelCalcalation();
}
myService.setData(data);
myService.startWork();
}
}
并在以下位置处理停止服务Activity：
public class CustomChordActivity extends Activity {
// ... code ...
@Override
public void onBackPressed() {
super.onBackPressed();
}
@Override
protected void onPause() {
if(isFinishing()) {
chordsView.stopService();
}
super.onPause();
}
@Override
protected void onStop() {
super.onStop();
}
@Override
protected void onDestroy() {
chordsView.unBindService();
super.onDestroy();
}
@Override
protected void finalize() throws Throwable {
super.finalize();
}
}