检测插入的设备

Question

我希望能够检测设备是否已插入。我希望能够以与连接状态相同的方式查询。这是可能的还是我需要创建一个侦听电池事件的广播接收器？

Answer 1

显然ACTION_BATTERY_CHANGED是“粘性广播”，这意味着您可以在广播后的任何时间注册并接收它。要获得插入状态，您可以执行以下操作：

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);
}