Android Studio Battery Checker 2-3

BatteryReceiver.java

public class BatteryReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {

        /* 省略 */

        if (action != null && action.equals(Intent.ACTION_BATTERY_CHANGED)) {

            /* 省略 */

            // バッテリー残量
            int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
            int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
            int percentage = level * 100 / scale;
            percentageLabel.setText(context.getString(R.string.percentage_label, percentage));
        }
      
    }
}