标签：parent baseline value hive 干什么 内存 lan div hold
首先我们要知道setTag方法是干什么的，SDK解释为
Tags
Unlike IDs, tags are not used to identify views. Tags are essentially an extra piece of information that can be associated with a view. They are most often used as a convenience to store data related to views in the views themselves rather than by putting them in a separate structure.
Tag不像ID是用标示view的。
Tag从本质上来讲是就是相关联的view的额外的信息。
它们经经常使用来存储一些view的数据。这样做很方便而不用存入另外的单独结构。
Tag有一个特点，绑定数据到指定控件（view），而不显示出来。
setTag是android的view类中非常实用的一个方法，
与setId()不同。findViewById找到的是对象本身。
而setTag(),取出来的是对象所指向的对象。
在同一个类中，存取数据非常方便，不用数据库建库，
也比sharePreference更节约内存。
setTag（Object tag)方法比較简单
比方
TextView tvExecutor = (TextView)findViewById(R.id.t);
tvExecutor.setTag(selectedUserMap);
这个selectedUserMap
能够使Map<String, String> selectedUserMap这个对象。
也能够是LinkedList<CarEntity> mList 这个对象。
能够存储各种暂时数据，可是还不能称其为存储方式。
在开发中，我们能够使用setTag(),getTag(),存取数据。
可不能够一个对象。设置多个Tag呢？答案是肯定的
在res/values/strings.xml中加入
<span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"><span style="line-height: 18px;"><span style="color:#cc0000;"><resources></span></span></span>
<span style="color:#cc0000;"><span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"><item type="id" name="tag_a</span><span style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif; background-color: rgb(240, 240, 240);">"></item></span></span>
<span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"><span style="color:#cc0000;"><item type="id" name="tag_b"></item></span></span>
<span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"><span style="color:#cc0000;"></resources></span></span>
<span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"> </span>
在activity中，使用的时候写成
<span face="Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif" style="font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif;"></span>
<code style="border: 0px; vertical-align: baseline; background-color: rgb(238, 238, 238); font-family: Consolas, Menlo, Monaco, ‘Lucida Console‘, ‘Liberation Mono‘, ‘DejaVu Sans Mono‘, ‘Bitstream Vera Sans Mono‘, ‘Courier New‘, monospace, serif; padding: 0px; margin: 0px;"><span style="color:#cc0000;"><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"><span style="font-family: Arial; font-size: 14px; line-height: 26px;">tvExecutor</span></span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">.</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">setTag</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">(</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">R</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">.</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"><span color="#00008b">id.tag_a</span></span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">,</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"> </span><span class="str" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">"逗比"</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">);</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"> <span style="font-family: Arial; font-size: 14px; line-height: 26px;">tvExecutor</span></span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">.</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">setTag</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">(</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">R</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">.</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"><span color="#00008b">id.tag_b</span></span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">,</span><span class="pln" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;"> </span><span class="str" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">"2货"</span><span class="pun" style="border: 0px; vertical-align: baseline; background-color: transparent; padding: 0px; margin: 0px;">);</span></span></code>
其有用的最多的是convertView中
1. 对于使用了LayoutInflater对象进行View扩充的Tag的使用
在之前。在adapter中，我们在getView中是这么些的代码：
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder();
convertView = inflater.inflate(R.layout.vlist2, null);
holder.img = (ImageView) convertView.findViewById(R.id.img);
holder.title = (TextView) convertView.findViewById(R.id.title);
holder.info = (TextView)
convertView.findViewById(R.id.info);
// setTag的妙用
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
……略
}
样例3 在onClick点击事件中。使用tag
View中的setTag(Onbect)表示给View加入一个格外的数据。以后能够用getTag()将这个数据取出来。
能够用在多个Button加入一个监听器，每一个Button都设置不同的setTag。这个监听器就通过getTag来分辨是哪个Button 被按下。
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class Main extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button1 = (Button) findViewById(R.id.Button01);
Button button2 = (Button) findViewById(R.id.Button02);
Button button3 = (Button) findViewById(R.id.Button03);
Button button4 = (Button) findViewById(R.id.Button04);
MyListener listener = new MyListener();
button1.setTag(1);
button1.setOnClickListener(listener);
button2.setTag(2);
button2.setOnClickListener(listener);
button3.setTag(3);
button3.setOnClickListener(listener);
button4.setTag(4);
button4.setOnClickListener(listener);
}
public class MyListener implements View.OnClickListener {
@Override
public void onClick(View v) {
int tag = (Integer) v.getTag();
switch (tag) {
case 1:
System.out.println("button1 click");
break;
case 2:
System.out.println("button2 click");
break;
case 3:
System.out.println("button3 click");
break;
case 4:
System.out.println("button4 click");
break;
}
}
}
}
Android setTag()与getTag(),与set多个setTag()
标签：parent baseline value hive 干什么 内存 lan div hold
原文地址：http://www.cnblogs.com/tlnshuju/p/6882871.html
