我想从Service
对象中调用Activity
对象中的方法,但是我发现无法正常地从MainActivity
中调用方法。
我希望我的代码能更好地解释我的意思:
服务:
public class Timer extends Service {
public Vibrator v;
public MainActivity ma;
public CountDownTimer mycounter;
public static final String MY_SERVICE = "de.example.timer.MY_SERVICE";
public IBinder onBind(Intent arg0)
{
return null;
}
public void onCreate()
{
super.onCreate();
ma = new MainActivity();
v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
startService();
}
public void startService()
{
mycounter = null; //delete counter
mycounter = new CountDownTimer(5000, 100){
public void onTick(long millisUntilFinished) {
//ma.timer.setText(ma.formatTime(millisUntilFinished+1000));
//ma.builder.setContentText("Timer: " + ma.formatTime(millisUntilFinished+1000)); //update Timer
//ma.notificationManager.notify(MainActivity.MY_NOTIFICATION_ID, ma.builder.build());
//It is not possible to call a methode this way in a service..
}
public void onFinish() {
//ma.timer.setText("00:00:00");
v.vibrate(1000);
mycounter.cancel();
mycounter.start();
}
};
mycounter.start();
}
public void onDestroy()
{
super.onDestroy();
mycounter.cancel();
}
}
活动:
public class MainActivity extends Activity {
private ImageButton imagebutton;
public Vibrator v;
public TextView timer;
public boolean pressed;
public String output;
public long waitingtime;
public Timer service;
public static final int MY_NOTIFICATION_ID = 1;
public NotificationManager notificationManager;
public Context context;
public Builder builder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
pressed = false;
waitingtime = 600000; // Standartmäßig auf 10 min
v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
imagebutton = (ImageButton) findViewById(R.id.imageButton1);
imagebutton.setBackgroundResource(R.drawable.start);
timer = (TextView) findViewById(R.id.timer);
timer.setText(formatTime(waitingtime));
Intent intent = new Intent (this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
| Intent.FLAG_ACTIVITY_SINGLE_TOP);
PendingIntent pend = PendingIntent.getActivity(this, 0, intent, 0);
notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
context = getApplicationContext();
builder = new NotificationCompat.Builder(context)
.setSmallIcon(R.drawable.notlogosmall)
.setContentTitle("Start!")
.setContentText("Timer set to " + waitingtime/1000 + " seconds")
.setContentIntent (pend)
.setTicker("Go!")
.setWhen(System.currentTimeMillis())
.setDefaults(0)
.setAutoCancel(false)
.setOngoing(true);
}
public void press(View view){
if(pressed == false){
imagebutton.setBackgroundResource(R.drawable.stop);
pressed = true;
notificationManager.notify(MY_NOTIFICATION_ID, builder.build()); //Notification
v.vibrate(100);
hidebuttons();
startService(new Intent(Timer.MY_SERVICE));
}
else{
imagebutton.setBackgroundResource(R.drawable.start);
pressed = false;
notificationManager.cancel(1);
timer.setText(formatTime(waitingtime));
showbuttons();
stopService(new Intent(Timer.MY_SERVICE));
v.vibrate(100);
}
}
如何从另一个类的对象中调用一个对象的方法?
一种简化的方法是从Activity发送一个意图,并在Service的onStartCommand()方法中对其进行处理。不要忘记提供正确的操作/附加意图,并在onStartCommand()]中进行检查
编辑:
活动:
添加私人班级:
private class CustomReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { if (intent.getAction().equals(ACTION_CUSTOM_ACTION)) { doCustomAction(); } } }
添加私人字段:
private CustomReceiver mCustomReceiver;
在onCreate()方法中:
mCustomReceiver = new CustomReceiver();
在onResume()或其他生命周期方法中:
(至上一步)生命周期方法中IntentFilter filter = new IntentFilter(ACTION_CUSTOM_ACTION); registerReceiver(mCustomReceiver , filter);
在onPause()或其他paired
unregisterReceiver(mCustomReceiver );
在活动中,只要您想调用使用Service方法:
startService(new Intent(SOME_ACTION));
在使用中:
@Override public int onStartCommand(Intent intent, int flags, int startId) { if (intent == null) { return START_STICKY; } String action = intent.getAction(); if (action == null) { return START_STICKY; } else if (action.equals(SOME_ACTION)) { invokeSomeServiceMethod();// here you invoke service method } return START_STICKY; }
注意,
START_STICKY
可能不是您的最佳选择,请阅读文档中的模式。
然后,当您想通知活动已完成时,请致电:
startActivity(ACTION_CUSTOM_ACTION);
这将触发广播接收者,您可以在其中处理结束事件。
似乎有很多代码,但实际上没有什么困难。
接受的答案没有错,但不必要的复杂。