Checks if device is charging

checkForPower.java

private boolean checkForPower() { 
        // It is very easy to subscribe to changes to the battery state, but you can get the current 
        // state by simply passing null in as your receiver.  Nifty, isn't that? 
        IntentFilter filter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        Intent batteryStatus = this.registerReceiver(null, filter);
 
 
        // There are currently three ways a device can be plugged in. We should check them all. 
        int chargePlug = batteryStatus.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
        boolean usbCharge = (chargePlug == BatteryManager.BATTERY_PLUGGED_USB);
        boolean acCharge = (chargePlug == BatteryManager.BATTERY_PLUGGED_AC);
        boolean wirelessCharge = false;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            wirelessCharge = (chargePlug == BatteryManager.BATTERY_PLUGGED_WIRELESS);
        } 
        return (usbCharge || acCharge || wirelessCharge);
    } 
}