我有一个具有 CountdownTimer 的后台服务。随着 CountdownTimer 倒计时，我向 Activity 发送广播。当 CountdownTimer 倒计时时，Activity 会收到警报，我可以停止服务并取消注册接收器。
我已将正常的接收器注销方法从 onStop 和 onPause 移到我自己的方法中，一旦收到带有“timer_finished”的广播，我就会调用该方法。这样我就可以在不注销的情况下离开 Activity。
如果用户当前正在查看 Activity，则一切正常。如果用户离开 Activity，则 CoundownTimer 仍在运行，但 Activity 没有接收到广播。
我该如何做到这一点，以便 Activity 接收最终广播“timer_finished”？
public class CountDownBroadcastService extends Service {
private static final String TAG = CountDownBroadcastService.class.getSimpleName();
public static final String COUNTDOWN_BR = "com.carefreegroup.rr3.countdown_br";
Intent bi = new Intent(COUNTDOWN_BR);
CountDownTimer cdt = null;
Context mContext;
@Override
public void onCreate() {
super.onCreate();
mContext = this;
Log.i(TAG, "Starting timer...");
cdt = new CountDownTimer(10000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
Log.i(TAG, "Countdown seconds remaining: " + millisUntilFinished / 1000);
bi.putExtra("countdown", millisUntilFinished);
bi.putExtra("timer_status", "timer_not_finished");
sendBroadcast(bi);
}
@Override
public void onFinish() {
Log.i(TAG, "Timer finished");
bi.putExtra("timer_status", "timer_finished");
sendBroadcast(bi);
}
};
cdt.start();
}
@Override
public void onDestroy() {
cdt.cancel();
Log.i(TAG, "Timer cancelled");
super.onDestroy();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e(TAG, "start of oncreate");
setContentView(R.layout.loneworker);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.drawable.ic_launcher);
setTitle("Lone Worker");
nfcscannerapplication = (NfcScannerApplication) getApplication();
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
tvCountDown = (TextView)findViewById(R.id.tvloneworkercountdown);
callFinished = (Button)findViewById(R.id.buttonlwcallfinished);
callFinished.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Log.e(TAG, "inside callFinished");
//maybe alert carer is safe***************************************
setCountDownFinished();
}
});
startService(new Intent(this, CountDownBroadcastService.class));
Log.i(TAG, "Started service");
}//end of onCreate
private BroadcastReceiver br = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
updateGUI(intent); // or whatever method used to update your GUI fields
}
};
public void onResume() {
super.onResume();
registerReceiver(br, new IntentFilter(CountDownBroadcastService.COUNTDOWN_BR));
Log.i(TAG, "Registered broacast receiver");
}
private void updateGUI(Intent intent) {
if (intent.getExtras() != null) {
long millisUntilFinished = intent.getLongExtra("countdown", 0);
//Log.i(TAG, "Countdown seconds remaining: " + millisUntilFinished / 1000);
String status = intent.getStringExtra("timer_status");
if(status.equalsIgnoreCase("timer_not_finished")){
tvCountDown.setText("Countdown seconds remaining: " + millisUntilFinished / 1000);
}else if(status.equalsIgnoreCase("timer_finished")){
setCountDownFinished();
}
}
}//end of updateGUI
public void setCountDownFinished(){
tvCountDown.setText("0");
unregisterReceiver(br);
Log.i(TAG, "Unregistered broacast receiver");
stopService(new Intent(this, CountDownBroadcastService.class));
Log.e(TAG, "Stopped CountDownBroadcastService");
}// end of setCountDownFinished()
}