How can I launch an android app on upon pressing the volume up or volume down button?

Question

I have a requirements in a personal safety app where a user has to launch an app as soon as possible via pressing the volume up or volume down button. What is the procedure to add this functionality?

Alcaraz

really an interesting question!! – Flatus

if my answer is feasible than raise and accept that we can close it. – Flatus

Answer 1

There is no broadcast event for volume change.

However, there is an undocumented action called "android.media.VOLUME_CHANGED_ACTION" which you could use, but it probably won't work on all devices/versions so it is not recommended.

Using other buttons (e.g. media buttons) would be possible though.

EDIT: Code sample (using the undocumented action):

AndroidManifest.xml

...
<receiver android:name="VolumeChangeReceiver" >
    <intent-filter>
        <action android:name="android.media.VOLUME_CHANGED_ACTION" />
    </intent-filter>
</receiver>
...

VolumeChangeReceiver.java

public class VolumeChangeReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals("android.media.VOLUME_CHANGED_ACTION")) {
            int newVolume = intent.getIntExtra("android.media.EXTRA_VOLUME_STREAM_VALUE", 0);
            int oldVolume = intent.getIntExtra("android.media.EXTRA_PREV_VOLUME_STREAM_VALUE", 0);
            if (newVolume != oldVolume) {
                Intent i = new Intent();
                i.setClass(context, YourActivity.class);
                i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(i);
            }
        }
    }
}

See this question if you want to unlock the screen when launching your app.

Stationery

@MuhammadMaqsoodurRehman I added a code sample (based on my first and second links), I don't have the SDK now so it's not tested. Keep in mind that since this is an unofficial method, it will not work on all devices/versions. – Stationery

Answer 2

I've used this code to listen for the volume button before,

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ((keyCode == KeyEvent.KEYCODE_VOLUME_DOWN)){
        //Do something
    }
    if ((keyCode == KeyEvent.KEYCODE_VOLUME_UP)){
        //Do something
    }
    return true;
}

This method gets event of volume up and down.

Doge

hi deepali he wants to launch app itself while this code may work from inside the acticity while before app launch is it possible?? – Flatus

@MuhammadMaqsoodurRehman than theres are two posibilities, either you need to do something with firm-ware or else you can launch app first time normally and from the next time you can launch with the help of broadcast receiver. – Flatus