Android ListView的使用

 1、定义简单的适配器形式。

首先定义一个Layout为listviewitem.xml. 里面有三个TextView。分别代表学号，姓名，班级。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/cuslistViewItem"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" 
        android:layout_marginLeft="10dp"
        android:layout_marginBottom="10dp"/>

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_marginLeft="10dp" 
        android:layout_marginBottom="10dp"/>

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_marginLeft="10dp"
        android:layout_marginBottom="10dp" />
</LinearLayout>

 在activity_main.xml中放一个ListView控件，很简单，不解释。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="50dp" >
    </ListView>

</RelativeLayout>

然后建立数据源

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		ListView lv = (ListView)this.findViewById(R.id.listView1);
		
		ArrayList<HashMap<String,String>> listSource = new ArrayList<HashMap<String,String>>();
		for(int num=1; num< 10; num++)
		{
			HashMap<String,String> map = new HashMap<String, String>();
			map.put("num",String.valueOf(num));
			map.put("name", "stu"+num );
			map.put("className", "software 2");
			listSource.add(map);
		}
		
		SimpleAdapter mStuInfo = new SimpleAdapter(
				this,listSource,R.layout.listviewitem, 
				new String[] {"num","name","className"}, 
				new int[]{R.id.textView1, R.id.textView2, R.id.textView3});
		
		lv.setAdapter(mStuInfo);
	}

}

 最后将listview绑定适配器的数据源。效果图如下图。

 当然可以加入ItemClick事件。

 lv.setOnItemClickListener(new ItemClickListener());

然后实现ItemClickListener。

	 class ItemClickListener implements OnItemClickListener {
		 //arg2 is the position
		 //arg3 is row number
		@Override
		public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
			// TODO Auto-generated method stub
			HashMap<String, String> item=(HashMap<String, String>) arg0.getItemAtPosition(arg2); 
			Toast.makeText(MainActivity.this, item.get("name"), Toast.LENGTH_LONG).show();
		}

	}

 ListView和GridView在此用法是一样的。可以把ListView控件换成GridView控件。

二、下面采用新的适配器形式。将添加学生图片，并重新组织布局。效果如下图:

代码如下：

重新设计的listviewitem.xml.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/cuslistViewItem"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_marginBottom="10dp" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" 
        android:layout_toRightOf="@+id/imageView1"
        android:layout_marginLeft="10dp"
        android:layout_marginBottom="10dp"/>

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_toRightOf="@+id/textView1" 
        android:layout_marginLeft="10dp" 
        android:layout_marginBottom="10dp"/>

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_toRightOf="@+id/imageView1"
        android:layout_below="@+id/textView1"
        android:layout_marginLeft="10dp"
        android:layout_marginBottom="30dp" />
</RelativeLayout>

重新的数据源。建立了MyListViewAdapter类继承BaseAdapter。

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		ListView lv = (ListView)this.findViewById(R.id.listView1);
		
		ArrayList<HashMap<String,String>> listSource = new ArrayList<HashMap<String,String>>();
		for(int num=1; num< 10; num++)
		{
			HashMap<String,String> map = new HashMap<String, String>();
			map.put("photo", String.valueOf(R.drawable.ic_launcher));
			map.put("num",String.valueOf(num));
			map.put("name", "stu"+num );
			map.put("className", "software 2");
			listSource.add(map);
		}
		lv.setAdapter(new MyListViewAdapter(listSource));
	}
	
	public class MyListViewAdapter extends BaseAdapter{

		View[] itemViews;
		public MyListViewAdapter(ArrayList<HashMap<String,String>> listSource)
		{
			itemViews = new View[listSource.size()];
			Iterator<HashMap<String, String>> it = listSource.iterator();
			HashMap<String,String> hash;
			int i = 0;
			try{
				while(it.hasNext())
				{
					hash = it.next();
					itemViews[i] =  makeItemView(hash);
					i++;
				}
			}catch(Exception e){
				Log.e("Error", e.getMessage());
				e.printStackTrace();
			}
	
		}
		
		private View makeItemView(HashMap<String,String> map) {  
			
			            if(map == null || map.isEmpty()) return null;
			            LayoutInflater inflater = (LayoutInflater) MainActivity.this  
			                  .getSystemService(Context.LAYOUT_INFLATER_SERVICE);  
			            
			            // 使用View的对象itemView与R.layout.item关联   
			            View itemView =  inflater.inflate(R.layout.listviewitem, null);  
			  
			            TextView title = (TextView) itemView.findViewById(R.id.textView1);  
			            title.setText(map.get("num"));  
			            Log.e("num" , map.get("num"));
			            
			            TextView text = (TextView) itemView.findViewById(R.id.textView2);  
			            text.setText(map.get("name"));
			            Log.e("name", map.get("name"));
			            
			            TextView text2 = (TextView) itemView.findViewById(R.id.textView3);  
			            text2.setText(map.get("className")); 
			            Log.e("className", map.get("className"));
			            
			            ImageView image = (ImageView) itemView.findViewById(R.id.imageView1);  
			            image.setImageResource(Integer.parseInt(map.get("photo"))); 
			            Log.e("photo", map.get("photo"));
			              
			            return itemView;  
			       } 

		
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return itemViews.length;
		}

		@Override
		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return itemViews[position];
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			if(convertView == null)
				return itemViews[position];
			return convertView;
		}}

		}

}