第3章软件也要拼脸蛋3.5ListView

1.MainActivity.java

package com.example.yangyq.listviewtest;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;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 {    private List<Fruit> fruitList = new ArrayList<>();//    private String[] data={"Apple","Banana","Orange","Watermelon","Pear","Grape",//            "Pineapple","Strawberry","Cherry","Mango","Apple","Banana","Orange",//            "Watermelon","Pear","Grape", "Pineapple","Strawberry","Cherry","Mango"};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initFruits();        FruitAdapter adapter = new FruitAdapter(MainActivity.this,                R.layout.fruit_item,fruitList);        ListView listView =(ListView) findViewById(R.id.list_view);        listView.setAdapter(adapter);        listView.setOnItemClickListener(new AdapterView.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();            }        });//        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);    }    private void initFruits(){        for (int i = 0;i<2;i++){            Fruit apple = new Fruit("Apple",R.drawable.apple);            fruitList.add(apple);            Fruit banana = new Fruit("Banana",R.drawable.banana);            fruitList.add(banana);            Fruit orange = new Fruit("Orange",R.drawable.orange);            fruitList.add(orange);            Fruit watermelon = new Fruit("Watermelon",R.drawable.watermelon);            fruitList.add(watermelon);            Fruit pear = new Fruit("Pear",R.drawable.pear);            fruitList.add(pear);            Fruit grape = new Fruit("Grape",R.drawable.grape);            fruitList.add(grape);            Fruit pineapple = new Fruit("Pineapple",R.drawable.pineapple);            fruitList.add(pineapple);            Fruit strawberry = new Fruit("Strawberry",R.drawable.strawberry);            fruitList.add(strawberry);            Fruit cherry = new Fruit("Cherry",R.drawable.cherry);            fruitList.add(cherry);            Fruit mango = new Fruit("Mango",R.drawable.mango);            fruitList.add(mango);        }    }}

2.Fruit.java

package com.example.yangyq.listviewtest;/** * Created by yang.yq on 2017/8/15. */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 int getImageId(){        return imageId;    }}

3.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="wrap_content">    <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_vertical"        android:layout_marginLeft="10dp"        /></LinearLayout>

4.FruitAdapter.java

package com.example.yangyq.listviewtest;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;/** * Created by yang.yq on 2017/8/15. */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    public View getView(int position, View convertView, ViewGroup parent){        Fruit fruit = getItem(position);//获取当前项的Fruit实例        View view;        ViewHolder viewHolder;        if (convertView == null){            view = LayoutInflater.from(getContext()).inflate(resourceId,                    parent,false);            viewHolder =new ViewHolder();            viewHolder.fruitImage = (ImageView) view.findViewById(R.id.fruit_image);            viewHolder.fruitName = (TextView) view.findViewById(R.id.fruit_name);            view.setTag(viewHolder);//将ViewHolder存储在View中        } else {            view = convertView;            viewHolder = (ViewHolder) view.getTag();//重新获取ViewHolder        }//        View view = LayoutInflater.from(getContext()).inflate(resourceId,parent,false);//        ImageView fruitImage = (ImageView) view.findViewById(R.id.fruit_image);//        TextView fruitName = (TextView) view.findViewById(R.id.fruit_name);//        fruitImage.setImageResource(fruit.getImageId());//        fruitName.setText(fruit.getName());        viewHolder.fruitImage.setImageResource(fruit.getImageId());        viewHolder.fruitName.setText(fruit.getName());        return view;    }    class ViewHolder{        ImageView fruitImage;        TextView fruitName;    }}

5.activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <ListView        android:id="@+id/list_view"        android:layout_width="match_parent"        android:layout_height="match_parent"></ListView></LinearLayout>