Detecting the device being plugged in

问题:

I would like to be able to detect whether or not the device is plugged in. I would like to be able to just query that the same way we can do for the connectivity state. Is that possible or do I need to create a broadcast receiver that listens for the battery events?

回答1:

Apparently the ACTION_BATTERY_CHANGED is a "sticky broadcast" which means you can register for it and receive it any time after it has been broadcast. To get the plugged state you can do something like:

public void onCreate() {
    BroadcastReceiver receiver = new BroadcastReceiver() {
        public void onReceive(Context context, Intent intent) {
            int plugged = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, -1);
            if (plugged == BatteryManager.BATTERY_PLUGGED_AC) {
                // on AC power
            } else if (plugged == BatteryManager.BATTERY_PLUGGED_USB) {
                // on USB power
            } else if (plugged == 0) {
                // on battery power
            } else {
                // intent didnt include extra info
            }
        }
    };
    IntentFilter filter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
    registerReceiver(receiver, filter);
}