How to detect app opening event

Question

I have a requirement that whenever an app is opened by user, an event should be generated based on which I have to do some processing in my app. I realize that android do not broadcast that event. Hence, I am stuck and looking for a work around.

I have also come across some apps that do the similar thing such as:

Avast Mobile Security: Scans the app when it is opened.

Vault: Shows password keypad when a locked app is opened.

Can anyone tell me how these apps are detecting the app opening event or point me in right direction to do.

I have previously done some Windows API Hooking and not sure if I could use this technique in android also. I have come across some runtime code injection frameworks like "Cydia Substrate" and "Xposed". Can these things solve my problems?

score 0 · Answer 1 · answered Mar 27 '14 at 18:52

0

It is handled within each Activity's onStart() or onCreate() method. I would put your check inside onStart().

@Override
    protected void onStart()  { 
        super.onStart();
//..Do processing.
}

You can save certain items inside onStop or onPause methods so that data persists after the user leaves the App.

If it's a Fragment, then u have to do it in onAttach:

    @Override
    public void onAttach(Activity activity) {
//..Do Processing.
        super.onAttach(activity);    
    }

answered Mar 27 '14 at 18:52

Gene

10,819
1
66
58

You are talking about my own app. Actually I need to detect when any app is opened by the user not my own app. – Faheem Mar 28 '14 at 13:00
Hrm... maybe try BroadCast Receiver http://developer.android.com/intl/zh-tw/reference/android/content/BroadcastReceiver.html – Gene Mar 28 '14 at 17:52
Android does not broadcast the app opening event. So it cannot be done through broadcast receivers. I need some other solution – Faheem Mar 28 '14 at 18:52
@Faheem Thanks a lot! But if its, for example malicious process, thats starts for a seconds and then kills itself. There is a possibility that it will run between alarm checks, right? – eu.vl Jul 24 '14 at 08:40
Yes off course !!! You can reduce Alarm Period. If want some security related tasks (like detecting malicious process or application) ... I do not recommend this approach as this approach won't yield perfect results. – Faheem Jul 24 '14 at 08:56

score -1 · Accepted Answer · answered Jul 24 '14 at 05:43

I have solved the problem by taking a workaround. It is not the exact solution but my problem has been solved. What I have done is that I have used AlarmManager to launch a repeated service (say After 10 seconds) which checks for new application top of the activity stack every time. If the Application is different from the last application (already saved) this is the new app that has been opened. The major drawback of this approach is that it eats up battery but you can select a suitable period and do not wake up the device.

This service launching code is given below:

//Start a Service that is started every 5 seconds
AlarmManager alarm = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Calendar cal = Calendar.getInstance();
Intent intent = new Intent(MyActivity.this, MyService.class);
PendingIntent pintent = PendingIntent.getService(context, 0, intoo, 0);
alarm.setRepeating(AlarmManager.RTC, cal.getTimeInMillis(), 5*1000, pintent);

In MyService.java you should check for new application on top of the activity stack.

How to detect app opening event

2 Answers2