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

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?

like image 724
Muhammad Maqsoodur Rehman Avatar asked Jan 13 '14 08:01

Muhammad Maqsoodur Rehman


1 Answers

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.

like image 124
molnarm Avatar answered Sep 21 '22 21:09

molnarm