blocks|key|2158323|text|表现不好吗？还是没什么关系？|type|blockquote|depth|inlineStyleRanges|entityRanges|data|2158324|这不重要。设置者只分配对象。|unstyled|2158325|如果我多次设置侦听器，它是否会覆盖以前的侦听器，还是会为该事件设置多个侦听器？|2158326|在您的复选框的每个实例中，只有一个名为setOnCheckedChangeListener。ListView是一个特殊的案例，因为它的循环机制。|offset|length|style|CODE|2158327|entityMap^0|0|0|0|J|Q|1A|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$]]|$1|E|3|F|5|6|7|Q|8|@]|9|@]|A|$]]|$1|G|3|H|5|D|7|R|8|@$I|S|J|T|K|L]|$I|U|J|V|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|D|7|W|8|@]|9|@]|A|$]]]|N|$]]

<blockquote>
 Is it bad in terms of performance? Or it doesn't matter?
</blockquote>

It does not matter. The setter just assign the object.

<blockquote>
 And if I set the listener multiple times whether it will overwrite
 previous listener or will i have multiple listeners for this event?
</blockquote>

you will have just one for each instance of the checkbox upon you called <code>setOnCheckedChangeListener</code>. The <code>ListView</code> is particular case due of its recycling mechanism

blocks|key|2158348|text|您设置的每个侦听器都将覆盖前一个监听器(如果有的话)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2158349|设置一个侦听器或其他任何东西都会消耗大量的时间，但是这里还创建了一个新的匿名类，这将花费更长的时间。|2158350|为了最大限度地提高性能，我要做一些调整：|2158351|使用convertViews缓存视图|ordered-list-item|offset|length|style|CODE|2158352|使用ViewHolder模式避免多次findViewById调用|2158353|对所有复选框使用单个侦听器，并仅在缓存的视图上设置它(如果是convertView+==+null)|2158354|将CheckBox所在项目的位置保存为复选框的标记|2158355|下面是一个例子：|2158356|private+static+class+ViewHolder+{
++++CheckBox+checkBox;
}

private+CompoundButton.OnCheckedChangeListener+mCheckListener+=+new+CompoundButton
++++++++.OnCheckedChangeListener()+{
++++@Override
++++public+void+onCheckedChanged(CompoundButton+buttonView,+boolean+isChecked)+{
++++++++Log.e("TAG",+"CheckBox+position:+"+%2B+buttonView.getTag());
++++}
};

@Override
public+View+getView(int+position,+View+convertView,+ViewGroup+parent)+{
++++ViewHolder+holder;
++++if+(convertView+==+null)+{
++++++++/*+Inflate+the+layout+here+*/

++++++++holder+=+new+ViewHolder();
++++++++holder.checkBox+=+(CheckBox)+convertView.findViewById(R.id.checkbox);
++++++++/*+Find+other+views+in+you+layout+here+*/

++++++++holder.checkBox.setOnCheckedChangeListener(mCheckListener);
++++++++//+Set+the+holder+as+tag,+so+you+can+fetch+it+later+for+re-use
++++++++convertView.setTag(holder);
++++}+else+{
++++++++//+Fetch+the+holder
++++++++holder+=+(ViewHolder)+convertView.getTag();
++++}

++++//+Set+the+checkbox+position
++++holder.checkBox.setTag(position);

++++return+convertView;
}|code-block|syntax|javascript|2158357|如果您不熟悉使用convertViews和ViewHolder模式，则应该查看解释这一切的ListView的世界。|2158358|entityMap|0|LINK|mutability|MUTABLE|url|https://www.youtube.com/watch?v=wDBM6wVEO70^0|0|0|0|2|B|0|2|A|I|C|0|U|J|0|0|0|0|8|C|L|A|19|B|0|0^^$0|@$1|2|3|4|5|6|7|19|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1A|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1B|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|1C|8|@$I|1D|J|1E|K|L]]|9|@]|A|$]]|$1|M|3|N|5|H|7|1F|8|@$I|1G|J|1H|K|L]|$I|1I|J|1J|K|L]]|9|@]|A|$]]|$1|O|3|P|5|H|7|1K|8|@$I|1L|J|1M|K|L]]|9|@]|A|$]]|$1|Q|3|R|5|H|7|1N|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1O|8|@]|9|@]|A|$]]|$1|U|3|V|5|W|7|1P|8|@]|9|@]|A|$X|Y]]|$1|Z|3|10|5|6|7|1Q|8|@$I|1R|J|1S|K|L]|$I|1T|J|1U|K|L]]|9|@$I|1V|J|1W|1|1X]]|A|$]]|$1|11|3|-4|5|6|7|1Y|8|@]|9|@]|A|$]]]|12|$13|$5|14|15|16|A|$17|18]]]]

Each listener that you set will overwrite the previous one (if any). Setting a listener, or anything else, will consume a super small amount of time, however here you're also creating a new anonymous class which will take longer.

For the maximum performance, I would make a few adjustments:

<ol>
<li>Use <code>convertView</code>s to cache the views</li>
<li>Use <code>ViewHolder</code> pattern to avoid multiple <code>findViewById</code> calls</li>
<li>Use a single listener for all checkboxes and set it only on the cached views (if <code>convertView == null</code>)</li>
<li>Save the position of the item that the CheckBox is located in as the CheckBox's tag</li>
</ol>

Here's an example:

<pre><code>private static class ViewHolder {
 CheckBox checkBox;
}

private CompoundButton.OnCheckedChangeListener mCheckListener = new CompoundButton
 .OnCheckedChangeListener() {
 @Override
 public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
 Log.e("TAG", "CheckBox position: " + buttonView.getTag());
 }
};

@Override
public View getView(int position, View convertView, ViewGroup parent) {
 ViewHolder holder;
 if (convertView == null) {
 /* Inflate the layout here */

 holder = new ViewHolder();
 holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkbox);
 /* Find other views in you layout here */

 holder.checkBox.setOnCheckedChangeListener(mCheckListener);
 // Set the holder as tag, so you can fetch it later for re-use
 convertView.setTag(holder);
 } else {
 // Fetch the holder
 holder = (ViewHolder) convertView.getTag();
 }

 // Set the checkbox position
 holder.checkBox.setTag(position);

 return convertView;
}
</code></pre>

If you're not familiar with using <code>convertViews</code> and the <code>ViewHolder</code> pattern you should watch <a href="https://www.youtube.com/watch?v=wDBM6wVEO70" rel="nofollow">The World of ListView</a> that explains it all.

I've a question about ListView and listeners. 
Suppose i have a listview in my app. Each item of it contains a checkbox. 
And i've the following code:

<pre><code>public View getView(final int position, View convertView, ViewGroup parent) {

 CheckBox checkbox = (CheckBox)v.findViewById(R.id.checkbox);

 checkbox.setOnCheckedChangeListener(new OnCheckedChangeListener(){

 public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
 // some code
 } 
 });

}
</code></pre>

As you can see I set setOnCheckedChangeListener every time when getView method is called.
So is it right way to set listener? Or should I set it once? Is it bad in terms of performance? Or it doesn't matter? And if I set the listener multiple times whether it will overwrite previous listener or will i have multiple listeners for this event?

Multiple listeners

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个关于ListView和听众的问题。假设我的应用程序中有一个列表视图。其中的每一项都包含一个复选框。我有以下代码：public View getView(final int position, View convertView, ViewGroup parent) {    CheckBox checkbox =...

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