how to update the battery level for every 5seconds in ble in android

Solution 1:

If I well understood your question, you will need a Timer in order to check you battery level regularly.

For instance, you could use this code after starting your device control activity, maybe at the end of the onServiceConnected method :

please put the timer at the end of onServiceConnected() method of mServiceConnection object

Timer timer = new Timer("batteryTimer");
TimerTask task = new TimerTask() {
@Override
public void run() {
mBluetoothLeService.getBattery();
}
};
timer.scheduleAtFixedRate(task, 0, 5000);

And do not forget to call timer.cancel() when the activity is finishing.

And in the service, you could put something like that :

public void getBattery() {

if (mBluetoothGatt == null) {
Log.e(TAG, "lost connection");
} 

BluetoothGattService batteryService = mBluetoothGatt.getService(Battery_Service_UUID);
if(batteryService == null) {
Log.d(TAG, "Battery service not found!");
return;
}

BluetoothGattCharacteristic batteryLevel = batteryService.getCharacteristic(Battery_Level_UUID);
if(batteryLevel == null) {
Log.d(TAG, "Battery level not found!");
return;
}

mBluetoothGatt.readCharacteristic(batteryLevel);
}

It is an example which would need to be modified but that gives you an idea on how to do it.

Somebody already did access to the battery value in the link below : How to get the battery level after connect to the BLE device?