android UI之ListView的自定义

首先还是上效果图，该ListView由四个控件组成，左边是一个图标，中间是两个TextView用于显示标题和描述，右边是一个TextView用于显示时间。

编写每一项对应的实体类

package cn.edu.zafu.myapplication;

/**
 * Created by Administrator on 2015/1/1.
 */
public class Item {
    private int resId;
    private String title;
    private String description;
    private String time;

    public Item(int resId, String title, String description, String time) {
        this.resId = resId;
        this.title = title;
        this.description = description;
        this.time = time;
    }

    public int getResId() {
        return resId;
    }

    public void setResId(int resId) {
        this.resId = resId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getTime() {
        return time;
    }

    public void setTime(String time) {
        this.time = time;
    }
}

编写每一项对应的布局文件

<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="wrap_content"
    android:minHeight="60dp"
    tools:context=".MainActivity">
    <ImageView
        android:id="@+id/item_icon"
        android:layout_width="32dp"
        android:layout_height="32dp"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="10dp"
        android:layout_centerVertical="true"
        />
    <LinearLayout
        android:layout_toRightOf="@id/item_icon"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_centerVertical="true"
        android:layout_marginLeft="10dp"
        android:gravity="center_vertical"
        android:orientation="vertical"
        >
        <TextView
            android:id="@+id/item_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            />
        <TextView
            android:id="@+id/item_description"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#aaa"
            android:textSize="15sp"
            />
        </LinearLayout>
        <TextView
            android:id="@+id/item_time"
            android:layout_width="60dp"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:textSize="12sp"
            />
</RelativeLayout>

主布局文件

<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"
    tools:context=".MainActivity">

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

        ></ListView>

</RelativeLayout>

继承ArrayAdapter编写适配器

package cn.edu.zafu.myapplication;

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;

import java.util.List;


public class MyArrayAdapter extends ArrayAdapter<Item> {
    private int resourceId;
    public MyArrayAdapter(Context context, int resource, List<Item> objects) {
        super(context, resource, objects);
        this.resourceId=resource;
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Item item = getItem(position);
        View view;
        ViewHolder viewHolder;
        if (convertView == null) {
            view = LayoutInflater.from(getContext()).inflate(resourceId, null);
            viewHolder=new ViewHolder();
            viewHolder.icon= (ImageView) view.findViewById(R.id.item_icon);
            viewHolder.title= (TextView) view.findViewById(R.id.item_title);
            viewHolder.description= (TextView) view.findViewById(R.id.item_description);
            viewHolder.time= (TextView) view.findViewById(R.id.item_time);
            view.setTag(viewHolder);
        } else {
            view = convertView;
            viewHolder= (ViewHolder) view.getTag();
        }
        viewHolder.icon.setImageResource(item.getResId());
        viewHolder.title.setText(item.getTitle());
        viewHolder.description.setText(item.getDescription());
        viewHolder.time.setText(item.getTime());
        return view;
    }
    class ViewHolder{
        ImageView icon;
        TextView title;
        TextView description;
        TextView time;
    }
}

Activity的代码

package cn.edu.zafu.myapplication;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

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


public class MainActivity extends ActionBarActivity {
    private List<Item> items=new ArrayList<Item>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initMenus();//初始化数据
        MyArrayAdapter adapter=new MyArrayAdapter(this,R.layout.item_layout,items);//新建自己的适配器
        ListView listView= (ListView)findViewById(R.id.listview);
        listView.setAdapter(adapter);//设置适配器
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Item item=items.get(position);//获得点击项对应实体类
                Toast.makeText(getApplicationContext(),item.getTitle(),Toast.LENGTH_SHORT).show();
            }
        });
    }

//数据初始化
    private void initMenus() {
        Item train=new Item(R.drawable.car,"ECMobile","蓝天神鹰","下午1:15");
        items.add(train);
        Item road=new Item(R.drawable.car,"YiiBook讨论群","UM5","下午2:23");
        items.add(road);
        Item history=new Item(R.drawable.car,"腾讯新闻","上海踩踏事件伤者惊魂","下午12:15");
        items.add(history);
    }
}

在实现的过程中主要遇到两个问题

第一个是ListView最下面的一项的横线不见了，解决方法是将ListViewd layout_height设为match_parent而不是wrap_content

第二是设置了子项的高度后不起作用，解决方法是设置layout_height属性为wrap_content，增加minHeight属性即此文中的minHeight="60dp"