EditText延迟搜索

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使用Handler的延迟发送实现：

private static final int MESSAGE_SEARCH = 0x1;
private static long INTERVAL = 1000; // 输入变化时间间隔

Handler mHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if (msg.what == MESSAGE_SEARCH){
                mTextView.setText("搜索key:" + mEditText.getText().toString());
            }
        }
};

// 设置监听
mEditText.addTextChangedListener(new TextWatcher() {

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) { }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {}

    @Override
    public void afterTextChanged(Editable s) {
        if (mHandler.hasMessages(MESSAGE_SEARCH)) {
            mHandler.removeMessages(MESSAGE_SEARCH);
        }
            mHandler.sendEmptyMessageDelayed(MESSAGE_SEARCH, INTERVAL);
        }
    });

一般使用Handler会有一个内存泄漏的提示：

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可以使用WeakReference弱引用来避免：

    MyHandler mHandler = new MyHandler(this);

    private static class MyHandler extends Handler {
        WeakReference<SearchEditActivity> mActivityReference;

        MyHandler(SearchEditActivity activity) {
            mActivityReference= new WeakReference<SearchEditActivity>(activity);
        }

        @Override
        public void handleMessage(Message msg) {
            SearchEditActivity activity = mActivityReference.get();
            if (activity != null) {
                activity.handleMessage(msg);
            }
        }
    }

    private void handleMessage(Message message){
        if (message.what == MESSAGE_SEARCH){
            mTextView.setText("搜索key:" + mEditText.getText().toString());
        }
    }

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