Android BatteryManager not reporting correct charging status

Question

I am having a little trouble getting whether a device is charging or not, but only on some devices. Namely the Sony Xperia Z and Xperia E.

The battery status always reports the phone as plugged out. I have tested the app on a Samsung Galaxy S4 and a Galaxy S2 and it works correctly on those.

I have a BroadcastReceiver, PowerConnectionReceiver, which is registered in the manifest to receive plugged in/plugged out events. When the receiver gets an intent, it calls another intent to get the current battery status:

@Override
public void onReceive(Context c, Intent intent) {
    Context context = c.getApplicationContext();


    try{

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

        int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
        boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING;

        int chargePlug = batteryStatus.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
        usbCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_USB;
        acCharge = chargePlug == BatteryManager.BATTERY_PLUGGED_AC;

        Toast.makeText(context, "Battery charging " + isCharging , Toast.LENGTH_SHORT).show();

        } catch (Exception e) {
        Log.e(TAG, e.toString());
        }

Can anybody see any obvious flaw in that code? I am stumped. Both the Sony Xperia Z I tried it on (where it doesn't work correctly) and the Samsung Galaxy S4 I tried it on are running Android 4.2.

Answer 1

Can anybody see any obvious flaw in that code?

You are assuming that ACTION_BATTERY_CHANGED has been broadcast, reflecting the new charging status, before whatever broadcast you are listening to ("plugged in/plugged out events") has been broadcast. I am not aware that this is a requirement. If the device sends its "plugged in/plugged out events" before ACTION_BATTERY_CHANGED, your code will be seeing the last ACTION_BATTERY_CHANGED, before the "plugged in/plugged out event".

Answer 2

in your code you have:

int status = batteryStatus.getIntExtra(BatteryManager.EXTRA_STATUS, -1);
boolean isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING;

in a try block and then when you log your output it is outside of the try block:

Toast.makeText(context, "Battery charging " + isCharging , Toast.LENGTH_SHORT).show();

Try putting your toast in your try block or expand the scope of isCharging:

public boolean isCharging;

public void method()
{
    try
    {
        ...
        isCharging = status == BatteryManager.BATTERY_STATUS_CHARGING;
    }catch(Exception e){...}
    Toast.makeText(context, "Battery charging " + isCharging , Toast.LENGTH_SHORT).show();
}