public class MainActivity extends Activity  {

    /**
     * 先宣告一個 IntentFilter 物件
     */
    private IntentFilter   mIntentFilter;


    private TextView textview;

    private MyHandler handler = new MyHandler(this);

    private class MyHandler extends Handler {
        private WeakReference<Context> mWeakReference;
        private String tag;

        public MyHandler(Context context) {
            mWeakReference = new WeakReference<Context>(context);

        }

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if (msg.what == 0) {

                mIntentFilter = new IntentFilter();
                mIntentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
                registerReceiver(mIntentReceiver, mIntentFilter);
                sendEmptyMessageDelayed(0, 15000);
            }
        }
    }



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        handler.sendEmptyMessageDelayed(0, 15000);

    }

    @Override
    protected void onResume() {
        super.onResume();
        // 註冊訊息處理器

    }

    //宣告訊息處理過程
    private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            //要看看是不是我們要處理的訊息
            if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
                //電池電量，數字
                Log.d("Battery", "" + intent.getIntExtra("level", 0));
                //電池最大容量
                Log.d("Battery", "" + intent.getIntExtra("scale", 0));
                //電池伏數
                Log.d("Battery", "" + intent.getIntExtra("voltage", 0));
                //電池溫度
                Log.d("Battery", "" + intent.getIntExtra("temperature", 0));

                //電池狀態，返回是一個數字
                // BatteryManager.BATTERY_STATUS_CHARGING 表示是充電狀態
                // BatteryManager.BATTERY_STATUS_DISCHARGING 放電中
                // BatteryManager.BATTERY_STATUS_NOT_CHARGING 未充電
                // BatteryManager.BATTERY_STATUS_FULL 電池滿
                Log.d("Battery", "" + intent.getIntExtra("status", BatteryManager.BATTERY_STATUS_UNKNOWN));

                //充電型別 BatteryManager.BATTERY_PLUGGED_AC 表示是充電器，不是這個值，表示是 USB
                Log.d("Battery", "" + intent.getIntExtra("plugged", 0));

                //電池健康情況，返回也是一個數字
                //BatteryManager.BATTERY_HEALTH_GOOD 良好
                //BatteryManager.BATTERY_HEALTH_OVERHEAT 過熱
                //BatteryManager.BATTERY_HEALTH_DEAD 沒電
                //BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE 過電壓
                //BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE 未知錯誤
                Log.d("Battery", "" + intent.getIntExtra("health", BatteryManager.BATTERY_HEALTH_UNKNOWN));
            }
        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 登出廣播
        unregisterReceiver(mIntentReceiver);
    }

}