Android之ListView常见四种Adapter的使用方法

文章目录

ListView需要使用适配器装载数据，而最常用的四种容器是ArrayAdapter，SimpleAdapter，BaseAdapter，SimpleCursorAdapter。通过简单的例子介绍这四种适配器使用，来熟悉ListView控件。

package com.carlos.listview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.ContactsContract.CommonDataKinds.Phone;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends Activity {

	private ListView listView1;
	private ListView listView2;
	private ListView listView3;
	private ListView listView4;
	private static final String TAG = "MainActivity";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		listView1 = getViewById(R.id.listview1);
		listView2 = getViewById(R.id.listview2);
		listView3 = getViewById(R.id.listview3);
		listView4 = getViewById(R.id.listview4);

		// android.R.layout.test_list_item，使用的是Android SDK自带的布局
		String[] datas = { "a", "b", "c" };
		ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
				MainActivity.this, android.R.layout.test_list_item, datas);
		listView1.setAdapter(arrayAdapter);

		List<Map<String, String>> list = new ArrayList<Map<String, String>>();
		Map<String, String> map = new HashMap<String, String>();
		map.put("name", "王北");
		map.put("age", "20");
		list.add(map);
		map = new HashMap<String, String>();
		map.put("name", "赵西");
		map.put("age", "23");
		list.add(map);
		map = new HashMap<String, String>();
		map.put("name", "刘北方");
		map.put("age", "21");
		list.add(map);
		SimpleAdapter simpleAdapter = new SimpleAdapter(MainActivity.this,
				list, R.layout.item, new String[] { "name", "age" }, new int[] {
						R.id.name, R.id.age });
		listView2.setAdapter(simpleAdapter);

		// 通过Cursor查找联系人名字和电话号码
		Cursor cursor = getContentResolver().query(
				ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null,
				null, null); // 获取手机联系人
		SimpleCursorAdapter cursorAdapter = new SimpleCursorAdapter(this,
				android.R.layout.simple_expandable_list_item_2, cursor,
				new String[] { Phone.DISPLAY_NAME, Phone.NUMBER }, new int[] {
						android.R.id.text1, android.R.id.text2 });
		listView3.setAdapter(cursorAdapter);

		Adapter adapter = new Adapter(this, list);
		listView4.setAdapter(adapter);

	}

	// 通过泛型简化findViewById
	<T extends View> T getViewById(int id) {
		try {
			return (T) findViewById(id);
		} catch (ClassCastException e) {
			Log.e(TAG, "Could not cast View to create class.", e);
			throw e;
		}
	}

}

外部自定义的一个BaseAdapter供主类调用

package com.carlos.listview;

import java.util.List;
import java.util.Map;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class Adapter extends BaseAdapter{

	private Context context;
	private List<Map<String, String>> list;
	
	//创建构造函数供外部类调用
	public Adapter(Context context, List<Map<String, String>> list) {
		super();
		this.context = context;
		this.list = list;
	}

	@Override
	public int getCount() {
		return list.size();
	}

	@Override
	public Object getItem(int arg0) {
		return list.get(arg0);
	}

	@Override
	public long getItemId(int arg0) {
		return arg0;
	}

	@Override
	public View getView(int arg0, View arg1, ViewGroup arg2) {
		
		ViewHolder holder;
		if (arg1==null) {
			holder=new ViewHolder();
			arg1=LayoutInflater.from(context).inflate(R.layout.item, null);
			holder.name=(TextView) arg1.findViewById(R.id.name);
			holder.age=(TextView) arg1.findViewById(R.id.age);
			arg1.setTag(holder);
		}else {
			holder=(ViewHolder) arg1.getTag();
		}
		holder.name.setText(list.get(arg0).get("name"));
		holder.age.setText(list.get(arg0).get("age"));
		return arg1;
	}

	class ViewHolder{
		TextView name;
		TextView age;
	}

}

主布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ArrayAdapter的例子:"
        />
    <ListView
        android:id="@+id/listview1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>
    <TextView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="SimpleAdapter的例子:"
        />
    <ListView
        android:id="@+id/listview2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>
    <TextView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="SimpleCursorAdapter的例子:"
        />
    <ListView
        android:id="@+id/listview3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>
    <TextView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="BaseAdapter的例子:"
        />
    <ListView
        android:id="@+id/listview4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

自定义的ListView的item.xml布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        
        <TextView 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="姓名:"
            />
        <TextView 
            android:id="@+id/name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <TextView 
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="年龄:"
            />
        <TextView 
            android:id="@+id/age"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            />
    </LinearLayout>
    
</LinearLayout>

由于用到查找手机联系人信息，所以AndroidMainfest.xml里面需加上下面这条读取联系人权限，不然会报错

<uses-permission android:name="android.permission.READ_CONTACTS" />

运行结果