Android UI 之 ListView

浏览数：20 / 时间：2015年06月11日

一、在代码中创建（不适用XML布局文件）

1.创建一个项目：ListViewLearn

2.修改MainActivity，继承于ListActivity

3.创建一个String数组，用来保存ListView中的现实内容

package com.learn.listviewlearn.utility;

public class Util {
    public static final String[] COUNTRYS = { "中国", "美国", "俄罗斯", "英国", "法国" };
}

4.修改onCreate方法，设置一个Adapter，数组中的内容在ListView中现实出来

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // setContentView(R.layout.activity_main);
        this.setListAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_dropdown_item_1line, Util.COUNTRYS));
    }

二、使用XML布局文件来定义ListView的样式

1.修改activity_main.xml文件，添加一个ListView，id必须为android:id="@android:id/list"

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

    <ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:background="#FFFFFF00" >
    </ListView>

</LinearLayout>

2.修改OnCreate方法

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.setListAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_dropdown_item_1line, Util.COUNTRYS));
    }

三、使用XML布局文件来定义ListViewItem的样式

1.首先创建一个list_view.xml的布局文件

<?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="horizontal" >

    <ImageView
        android:id="@+id/imageViewIcon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:contentDescription="@string/icon" >
    </ImageView>

    <TextView
        android:id="@+id/textViewContent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >
    </TextView>

</LinearLayout>

2.然后创建一个Adapter继承于BaseAdapter，主要修改getCount()和getView()方法

package com.learn.listviewlearn.adapter;

import com.learn.listviewlearn.R;
import com.learn.listviewlearn.utility.Util;

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

public class ListViewAdapter extends BaseAdapter {
    private Context context;

    public ListViewAdapter() {
        // TODO Auto-generated constructor stub
    }

    @Override
    public int getCount() {
        return Util.COUNTRYS.length;
    }

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

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.list_item, null);
            ItemViewCache itemViewCache = new ItemViewCache();
            itemViewCache.imageView = (ImageView)convertView.findViewById(R.id.imageViewIcon);
            itemViewCache.textView = (TextView)convertView.findViewById(R.id.textViewContent);
            convertView.setTag(itemViewCache);
        }
        
        ItemViewCache cache = (ItemViewCache) convertView.getTag();

        cache.imageView.setImageResource(Util.images[position]);
        cache.textView.setText(Util.COUNTRYS[position]);
        return convertView;
    }
    
    private static class ItemViewCache{
        public TextView textView;
        public ImageView imageView;
    }

}

Util.java

package com.learn.listviewlearn.utility;

import com.learn.listviewlearn.R;

public class Util {
    public static final String[] COUNTRYS = { "中国", "美国", "俄罗斯", "英国", "法国" };
    public static final int[] images = { R.drawable.ic_launcher,
            R.drawable.ic_launcher, R.drawable.ic_launcher,
            R.drawable.ic_launcher, R.drawable.ic_launcher };
}

四、为ListView添加Click事件。只需要在MainActivity中实现onListItemClick()方法

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        Toast.makeText(this, "你选择了" + Util.COUNTRYS[position], Toast.LENGTH_SHORT)
                .show();
    }