android-ListView的简单用法

1.为了方便，将讲解注释写到了代码中，这样应该便于观看，思路也比较连续

代码：

MainActivity.java

package com.king.listviewtest;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends Activity {

private static List<Fruit> fruitList = new ArrayList<Fruit>();
static{
Fruit apple = new Fruit("Apple",R.drawable.apple_btn);

Fruit apple1 = new Fruit("Banana",R.drawable.orage_btn);

Fruit apple2 = new Fruit("Pear",R.drawable.water_btn);

Fruit apple3 = new Fruit("Lemon",R.drawable.water_btn);

Fruit apple4 = new Fruit("peach",R.drawable.orage_btn);

Fruit apple5 = new Fruit("plum",R.drawable.apple_btn);

Fruit apple6 = new Fruit("nectarine",R.drawable.water_btn);

Fruit apple7 = new Fruit("honeydew",R.drawable.orage_btn);
fruitList.add(apple);
fruitList.add(apple1);
fruitList.add(apple2);
fruitList.add(apple3);
fruitList.add(apple4);
fruitList.add(apple5);
fruitList.add(apple6);
fruitList.add(apple7);

}

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/*String[] data = {"peach","Lemon","Pear","avocado","cantaloupe","Banana","Grape","raisins","plum","apricot","nectarine","honeydew","orange","tangerine"};
//android.R.layout.simple_list_item_1：android内置的布局文件，里面只有一个TextView，可用于简单的显示一段文本
ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1,data);
ListView listView = (ListView) findViewById(R.id.list_view);
listView.setAdapter(adapter);*/

//依次传入上下文，ListView子项布局的id,以及要适配的数据
FruitAdapter friuitAdapter = new FruitAdapter(MainActivity.this, R.layout.fruit_item, fruitList);
ListView listView = (ListView) findViewById(R.id.list_view);
//将构建好的适配器对象传递进去
listView.setAdapter(friuitAdapter);
//ListView的点击事件
listView.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Fruit fruit = fruitList.get(position);
Toast.makeText(MainActivity.this, fruit.getName(), Toast.LENGTH_SHORT).show();

}
});
}
}

FruitAdapter.java

package com.king.listviewtest;

import java.util.List;

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

public class FruitAdapter extends ArrayAdapter<Fruit>{

private int resourceId;

public FruitAdapter(Context context,int textViewResourceId,
List<Fruit> objects) {
super(context,textViewResourceId, objects);
resourceId = textViewResourceId;

}

@Override
//这个方法在每个子项被滚动到屏幕内的时候会被调用
public View getView(int position, View convertView, ViewGroup parent) {
Fruit fruit = getItem(position);//获取当前fruit实例

View view;
ViewHolder viewHolder;
//提升ListView的运行效率，convertView这个参数用于将之前加载好的布局进行缓存，以便之后可以重用
if(convertView == null){
viewHolder = new ViewHolder();
//使用LayoutInflater来为这个子项加载我们传入的布局，并分别调用他们的setImageResource，setText来显示
view = LayoutInflater.from(getContext()).inflate(resourceId, null);
viewHolder.fruitImage = (ImageView) view.findViewById(R.id.fruit_image);
viewHolder.fruitName = (TextView) view.findViewById(R.id.fruit_name);
view.setTag(viewHolder); //将viewHolder存储到View中，当convertView不为空的时候则调用view的getTag()方法，把ViewHolder重新取出
}else{
view = convertView;
viewHolder = (ViewHolder) view.getTag();
}

viewHolder.fruitImage.setImageResource(fruit.getImageId());
viewHolder.fruitName.setText(fruit.getName());

return view;
}

class ViewHolder{
ImageView fruitImage;
TextView fruitName;
}

}

Fruit.java

package com.king.listviewtest;

public class Fruit {

private String name;
private int imageId;

public Fruit(String name, int imageId) {
this.name = name;
this.imageId = imageId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getImageId() {
return imageId;
}
public void setImageId(int imageId) {
this.imageId = imageId;
}

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<!-- 先为ListView指定了一个id，然后将宽度和高度都设置为match_parent，这样ListView也就
占据了整个布局的空间 -->

<ListView
android:id="@+id/list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"

></ListView>

</LinearLayout>

fruit_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/fruit_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/fruit_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginLeft="10dip"
/>

</LinearLayout>

源代码：http://download.csdn.net/detail/wangxuewei111/8579529