How to determine whether battery is low intially?

Question

I registered to receive ACTION_BATTERY_LOW and ACTION_BATTERY_OKAY in an activity and change some behavior according to this.

But I want to know the initial state, when the activity starts. Currently I do it with the following code:

Intent intent = registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 100);
int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100);
boolean batteryLow = 
    (status == BatteryManager.BATTERY_STATUS_DISCHARGING 
           || status == BatteryManager.BATTERY_STATUS_NOT_CHARGING)
    && level * 100 / scale < 15;

This code is both too verbose and maybe different from what android thinks is low. For example, emulator does not report status==discharging, when I issue "power ac off" command to the telnet. I have to issue "power status discharging" as well. Not sure about real device.

Is there any other way?

Answer 1

As I have found out, the code in the question is the simplest possible one. The warning is shown at 15% battery level, and this value is not available through public API. There is also another level of 10%, when the screen dims. These values are defined during build time, maybe some manufacturers or android versions change it.

See also this answer.

Answer 2

Thats as verbose as i can make this

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

return BatteryManager.BATTERY_STATUS_DISCHARGING && level / (float)scale < 15;