用户打字时如何避免 EditText 上的多个触发器?

问题描述

当用户输入 EditText 时，我使用以下代码执行搜索:

I use the following code to perform search when user types in an EditText :

EditText queryView = (EditText) findViewById(R.id.querybox);
queryView.addTextChangedListener(new TextWatcher() {
  @Override
  public void afterTextChanged(Editable s) {
    triggerSearch(s.toString()); 
  }
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count, int after) {
  }
  @Override
  public void onTextChanged(CharSequence s, int start, int before, int count) {
  }
});

但是，当用户键入一个单词时，这会触发多次.也就是说，如果用户键入hello"，此代码将触发 5 次值(h"、he"、hel"、hell"、hello").通常，这会很好，但触发搜索很昂贵，我不想将资源浪费在没有多大用处的中间搜索上.我想要的是在用户开始键入后仅触发某个阈值的侦听器，或者是某种框架，它在调用 triggerSearch 之前在侦听器中等待，并且如果在该等待之前触发了另一个事件, 自行取消.

However, this triggers multiple times when the user is typing a word. That is if the user is typing "hello", this code will trigger 5 times with values ("h", "he" , "hel", "hell", "hello"). Normally, this would be fine but the triggered search is expensive and I don't want to waste resources on intermediate searches that are of no great use. What I want is either a listener that triggers only a certain threshold after the user starts typing, or some kind of framework, that waits in the listener before calling triggerSearch, and if another event is triggered before that wait, cancels itself.

推荐答案

由于找不到合适的事件接口，尝试触发延迟搜索.代码实际上非常简单和健壮.

Since couldn't find an appropriate event interface, tried triggering a delayed search. The code is actually pretty simple and robust.

private final int TRIGGER_SERACH = 1;
// Where did 1000 come from? It's arbitrary, since I can't find average android typing speed.
private final long SEARCH_TRIGGER_DELAY_IN_MS = 1000;

  private Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      if (msg.what == TRIGGER_SERACH) {
        triggerSearch();
      }
    }
  };

 queryView.addTextChangedListener(new TextWatcher() {

   @Override
   public void beforeTextChanged(CharSequence charSequence, int i, int i2, int i3) {

   }

   @Override
   public void onTextChanged(CharSequence charSequence, int i, int i2, int i3) {

   }

   @Override
   public void afterTextChanged(Editable s) {
    handler.removeMessages(TRIGGER_SERACH);
    handler.sendEmptyMessageDelayed(TRIGGER_SERACH, SEARCH_TRIGGER_DELAY_IN_MS);
   });

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