Android常见UI组件之ListView(一)
最后更新于:2022-04-01 20:16:39
**使用ListView显示一个长的项列表**
1、新建一个名为“BasicView5”的Android项目;
2、修改BasicView5.java文件,修改后的程序如下:
~~~
package com.example.basicview5;
import android.os.Bundle;
import android.app.Activity;
import android.app.ListActivity;
import android.view.Menu;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends ListActivity {
String[] presidents = { "Dwight D. Eisenhower", "John F. Kennedy",
"Lyndon B. Johnson", "Richard Nixon", "Gerald Ford",
"Jimmy Carter", "Ronald Reagan", "George H. W. Bush",
"Bill Clinton", "George W. Bush", "Barack Obama" };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// ---no need to call this---//
// setContentView(R.layout.activity_main)
setListAdapter(new ArrayAdapter(this,
android.R.layout.simple_expandable_list_item_1, presidents));
}
public void onListItemClick(ListView parent, View v, int position, long id) {
Toast.makeText(this, "You have selected " + presidents[position],
Toast.LENGTH_SHORT).show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
~~~
3、运行结果:如下图,为点击“Richard Nixon”后的样子:
![](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2016-08-23_57bc06b3db790.jpg)
详解:
(1)BasicView5类扩展了ListActivity类,ListActivity类扩展了Activity类并通过绑定到一个数据源来显示一个项列表;
(2)无需修改main.xml来包含ListView:ListActivity类本身已经包含了一个ListView,所以在onCreate()方法中,不需要调用setContentView()方法来从main.xml文件中加载用户界面;
(3)在onCreate()方法中,使用setListAdapter()方法来用一个ListView以编程方式填充活动的整个屏幕。ArrayAdapter对象管理将由ListView显示的字符串数组;
(4)单击ListView中的一个列表项时,会触发onListItemClick()方法;
下一篇来实现对ListView定制通用视图~
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