Get battery level and state in Android

You don't have to register an actual BroadcastReceiver as Android's BatteryManager is using a sticky Intent:

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
Intent batteryStatus = registerReceiver(null, ifilter);

int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);

float batteryPct = level / (float)scale;

return (int)(batteryPct*100);

This is from the official docs over at https://developer.android.com/training/monitoring-device-state/battery-monitoring.html.

Other answers didn't mention how to access battery status (chraging or not).

IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
Intent batteryStatus = context.registerReceiver(null, ifilter);

// Are we charging / charged?
int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING ||
                     status == BatteryManager.BATTERY_STATUS_FULL;

// How are we charging?
int chargePlug = batteryStatus.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
boolean usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
boolean acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;

try this function no need permisson or any reciver

void getBattery_percentage()
{
      IntentFilter ifilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
      Intent batteryStatus = getApplicationContext().registerReceiver(null, ifilter);
      int level = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
      int scale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
      float batteryPct = level / (float)scale;
      float p = batteryPct * 100;

      Log.d("Battery percentage",String.valueOf(Math.round(p)));
  }

To check battery percentage we use BatteryManager, the following method will return battery percentage.

Source Link

public static float getBatteryLevel(Context context, Intent intent) {
    Intent batteryStatus = context.registerReceiver(null,
            new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    int batteryLevel = -1;
    int batteryScale = 1;
    if (batteryStatus != null) {
        batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, batteryLevel);
        batteryScale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, batteryScale);
    }
    return batteryLevel / (float) batteryScale * 100;
}

one mistake in official docs, you must use double instead float. Because 0.53F * 100F = 52F

int level = batteryStatus != null ? 
batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) : -1; int scale = 
batteryStatus != null ? batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, -1) : -1; 
double batteryPct = (double) level / (double) scale; int percent = (int) (batteryPct * 100D);