Android(定制的ListView的界面）

1、运行时效果图：

2、Fruit.java(实体类)

//定义了一个水果的实类
public class Fruit {
    private int imageView;
    private String textView;
    public Fruit(int imageView, String textView) {
        this.imageView = imageView;
        this.textView = textView;
    }
    public int getImageView() {
        return imageView;
    }
    public String getTextView() {
        return textView;
    }
}

3、fruit_activity.xml(子布局)

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

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

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

4、 FruitAdapter.java(自定义的适配器)

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;

//定义一个适配器（泛型）
public class FruitAdapter extends ArrayAdapter<Fruit> {
    int textViewId;//在MainActivity中实例化传来的子布局ID

    public FruitAdapter(Context context, int resource, List objects) {
        super(context, resource, objects);
        textViewId = resource;
    }

    @Override
    //重写getView（）每个子项滚动到屏幕是被调用
    public View getView(int position, View convertView, ViewGroup parent) {
        Fruit fruit = getItem(position);//获取Fruit的对象
        //利用from()生成LayoutInflater实例，inflate第一的是子布局既是（在MainActivity中实例化传来的子布局ID），第二个是当前布局
        View view = LayoutInflater.from(getContext()).inflate(textViewId, parent, false);
        //获得子布局的实例设置值。
        ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
        TextView textView = (TextView) view.findViewById(R.id.textView);
        imageView.setImageResource(fruit.getImageView());
        textView.setText(fruit.getTextView());
        return view;
    }
}

5、activity_main.xml(父布局既是ListView)

<LinearLayout 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="com.example.jcs.myfruitlistview.MainActivity">
    
    <ListView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    ListView>

LinearLayout>

6、MainActivity.java(添加适配器)

package com.example.jcs.myfruitlistview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    List list = new ArrayList<>();
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initList();
        FruitAdapter fruitAdapter = new FruitAdapter(MainActivity.this, R.layout.fruit_activity, list);
        ListView listView = (ListView) findViewById(R.id.list);
        //ListView增加适配器
        listView.setAdapter(fruitAdapter);
    }
    //实例化数组
    private void initList() {
        for (int i = 0; i < 10; i++) {
            Fruit fruit1 = new Fruit(R.drawable.guan, "guan");
            Fruit fruit2 = new Fruit(R.drawable.hua, "hua");
            Fruit fruit3 = new Fruit(R.drawable.qin, "qin");
            list.add(fruit1);
            list.add(fruit2);
            list.add(fruit3);
        }
    }
}

7、文件位置

8、下面是优化（定制的ListView的界面）

主要是在getView（）中进行判断View是否存在？

**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;
//定义一个适配器（泛型）
public class FruitAdapter extends ArrayAdapter<Fruit> {
    int textViewId;//在MainActivity中实例化传来的子布局ID
    public FruitAdapter(Context context, int resource, List objects) {
        super(context, resource, objects);
        textViewId = resource;
    }
    @Override
    //重写getView（）每个子项滚动到屏幕是被调用
    public View getView(int position, View convertView, ViewGroup parent) {
        View view;
        ViewHolder viewHolder;
        Fruit fruit = getItem(position);//获取Fruit的对象
        //判断加载布局是否为空（null加载，不为null不加载）
        if (convertView == null) {
            view = LayoutInflater.from(getContext()).inflate(textViewId, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.imageView = (ImageView) view.findViewById(R.id.imageView);
            viewHolder.textView = (TextView) view.findViewById(R.id.textView);
            //将ViewHolder存放到View中
            view.setTag(viewHolder);
        } else {
            view = convertView;
            //重新获取ViewHolder
            viewHolder = (ViewHolder) view.getTag();
        }
        //用内部类的组件设置
        viewHolder.imageView.setImageResource(fruit.getImageView());
        viewHolder.textView.setText(fruit.getTextView());
        return view;
    }
    //定义内部类存放组件
    class ViewHolder {
        ImageView imageView;
        TextView textView;
    }
}**

9、增加点击事件（定制的ListView的界面）

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
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 AppCompatActivity {
    List list = new ArrayList<>();

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initList();
        FruitAdapter fruitAdapter = new FruitAdapter(MainActivity.this, R.layout.fruit_activity, list);
        final ListView listView = (ListView) findViewById(R.id.list);
        //ListView增加适配器
        listView.setAdapter(fruitAdapter);
        //注册setOnItemClickListener（）监听器
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView adapterView, View view, int i, long l) {
                //在数组中获取Fruit的实例
                Fruit fruit = list.get(i);
                Toast.makeText(MainActivity.this, fruit.getTextView(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    //实例化数组
    private void initList() {
        for (int i = 0; i < 10; i++) {
            Fruit fruit1 = new Fruit(R.drawable.guan, "guan");
            Fruit fruit2 = new Fruit(R.drawable.hua, "hua");
            Fruit fruit3 = new Fruit(R.drawable.qin, "qin");
            list.add(fruit1);
            list.add(fruit2);
            list.add(fruit3);
        }
    }
}