设备休眠时将Android应用置于前台

Question

I successfully used the AlarmManager to set an alarm in the future and I was able to have a BroadcastReceiver getting called at alarm time. I read that you can use the PowerManager to turn device on in case it went to sleep and use the KeyguardManager to unlock the device.

But I also need to start my app or bring it into foreground. Will this be done automatically? I can not find a hint to this in the Internet.

Answer 1

您可以通过以主要活动为目的在广播接收器中发送startActivity来实现。

Answer 2

Got it :)

//The Main Activity
public class FullscreenActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
    }

    Context context=this;
    Alarm alarm = new Alarm();

    public void onDummyButton(View view) {
        alarm.SetAlarm(this);
    }

}



//The Alarm Receiver
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;

import java.util.Calendar;

public class Alarm extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        //Log.d("Alarm", "onReceive");
        // Put here YOUR code.

        // Start the MainActivity
        Intent i = new Intent(context, FullscreenActivity.class);
        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(i);

        Toast.makeText(context, "Alarm !!!!!!!!!!", Toast.LENGTH_LONG).show(); // For example
    }

    public void SetAlarm(Context context)
    {
        AlarmManager am =( AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
        Intent i = new Intent(context, Alarm.class);
        PendingIntent pi = PendingIntent.getBroadcast(context, 0, i, 0);

        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis() + 1000 * 15);
        //calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY));
        //calendar.set(Calendar.MINUTE, calendar.get(Calendar.MINUTE)+1);

        am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 1000 * 60 * 10, pi); // Millisec * Second * Minute

        Toast.makeText(context, "Alarm scheduled for: " + calendar.get(Calendar.HOUR_OF_DAY)+':'+calendar.get(Calendar.MINUTE)+':'+calendar.get(Calendar.SECOND), Toast.LENGTH_LONG).show();
    }

    public void CancelAlarm(Context context)
    {
        Intent intent = new Intent(context, Alarm.class);
        PendingIntent sender = PendingIntent.getBroadcast(context, 0, intent, 0);
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        alarmManager.cancel(sender);
    }