【內存泄漏】Android內存泄漏---Handler

Handler咱們常常用在程序中，發送消息，然而這裏涉及到內存泄漏隱患，非靜態內部類引發的。

非靜態內部類引發內存泄漏，詳見http://blog.csdn.net/qq_29266921/article/details/54847402

舉個栗子：

public class MainActivity extends AppCompatActivity {

    private Handler mHandler = new Handler() {

        @Override

        public void handleMessage(Message msg) {

            //...

        }

    };

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        loadData();

    }

    private void loadData(){

        //...request

        Message message = Message.obtain();

        mHandler.sendMessage(message);

    }

}

建議去看上面的連接，而後你就會知道非靜態匿名內部類，和非靜態內部類引發內存泄漏緣由是同樣的。

上面的代碼能夠更加安全，修改以下：

public class MainActivity extends AppCompatActivity {

    private MyHandler mHandler = new MyHandler(this);

    private TextView mTextView ;

    private static class MyHandler extends Handler {

        private WeakReference<Context> reference;

        public MyHandler(Context context) {

            reference = new WeakReference<>(context);

        }

        @Override

        public void handleMessage(Message msg) {

            MainActivity activity = (MainActivity) reference.get();

            if(activity != null){

                activity.mTextView.setText("");

            }

        }

    }

  

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        mTextView = (TextView)findViewById(R.id.textview);

        loadData();

    }

  

    private void loadData() {

        //...request

        Message message = Message.obtain();

        mHandler.sendMessage(message);

    }

  

    @Override

    protected void onDestroy() {

        super.onDestroy();

        mHandler.removeCallbacksAndMessages(null);

    }

}

1.建立一個靜態Handler內部類，而後對Handler持有的對象使用弱引用，這樣在回收時也能夠回收Handler持有的對象。

2.mHandler.removeCallbacksAndMessages(null)移除消息隊列中全部消息和全部的Runnable。固然也能夠使用mHandler.removeCallbacks()或mHandler.removeMessages()來移除指定的Runnable和Message