请问这种写法会不会导致内存泄露：

       static class MyHandler extends Handler {
        WeakReference<Activity> mWeakReference = null;

        public MyHandler(SampleActivity activity) {
            mWeakReference = new WeakReference<Activity>(activity);
        }

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            SampleActivity activity = (SampleActivity) mWeakReference.get();
            if(activity == null) {
                return;
            } else {
                if(msg.what == 0) {
                    //do something
                }
            }
        }
    }

然后我在onCreate方法中初始化一个MyHandler的对象：

    private MyHandler mHandler = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initViews();
        mHandler = new MyHandler(this);
    }