Get battery level before broadcast receiver responds for Intent.ACTION_BATTERY_CHANGED

This is how to get the battery level without registering a receiver:

Intent batteryIntent = context.getApplicationContext().registerReceiver(null,
                    new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
int rawlevel = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
double scale = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
double level = -1;
if (rawlevel >= 0 && scale > 0) {
    level = rawlevel / scale;
}

It can use a null BroadcastReceiver because of the sticky nature of the broadcast.

It uses the getApplicationContext() trick in case you are in a intent receiver and get the exception:

android.content.ReceiverCallNotAllowedException:
IntentReceiver components are not
allowed to register to receive
intents

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