安卓開發學習筆記（16）定製ListView界面

MainActivity.java

package com.example.listviewtest;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

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

public class MainActivity extends AppCompatActivity {
private List<Fruit> fruitList=new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruit();//初始化水果數據
        FruitAdapter adapter=new FruitAdapter(MainActivity.this,R.layout.fruit_item,fruitList);
        ListView listView=findViewById(R.id.listView);
        listView.setAdapter(adapter);
    }
    private void initFruit()
    {
        for(int i=0;i<2;i++)
        {
            Fruit apple=new Fruit("Apple",R.drawable.apple_pic);
            fruitList.add(apple);
            Fruit banana=new Fruit("Banana",R.drawable.banana_pic);
            fruitList.add(banana);
            Fruit orange=new Fruit("Orange",R.drawable.orange_pic);
            fruitList.add(orange);
            Fruit watermelon=new Fruit("Watermelon",R.drawable.watermelon_pic);
            fruitList.add(watermelon);
            Fruit pear=new Fruit("Pear",R.drawable.pear_pic);
            fruitList.add(pear);
            Fruit grape=new Fruit("Grape",R.drawable.grape_pic);
            fruitList.add(grape);
            Fruit pineapple=new Fruit("Pineapple",R.drawable.pineapple_pic);
            fruitList.add(pineapple);
            Fruit strawberry=new Fruit("Strawberry",R.drawable.strawberry_pic);
            fruitList.add(strawberry);
            Fruit cherry=new Fruit("Cherry",R.drawable.cherry_pic);
            fruitList.add(cherry);
            Fruit mango=new Fruit("Mango",R.drawable.mango_pic);
            fruitList.add(mango);
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

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

</LinearLayout>

 Fruit.java

package com.example.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 int getImageId(){
        return imageId;
    }
}

fruit_item.xml

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

</LinearLayout>

FruitAdapter.java

package com.example.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 android.widget.ViewFlipper;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.List;

public class FruitAdapter extends ArrayAdapter<Fruit> {
    private int resourceId;
    public FruitAdapter(@NonNull Context context, int resource, @NonNull List<Fruit> objects) {
        super(context, resource, objects);
        resourceId=resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Fruit fruit=getItem(position);
        View view= LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
        ImageView fruitImage=view.findViewById(R.id.fruit_image);
        TextView fruitName=view.findViewById(R.id.fruit_name);
        fruitImage.setImageResource(fruit.getImageId());
        fruitName.setText(fruit.getName());
        return view;
    }
}

 

運行結果：

 

提升ListView速度

修改FruitAdapter.java

package com.example.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 android.widget.ViewFlipper;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.List;

public class FruitAdapter extends ArrayAdapter<Fruit> {
    private int resourceId;
    public FruitAdapter(@NonNull Context context, int resource, @NonNull List<Fruit> objects) {
        super(context, resource, objects);
        resourceId=resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        Fruit fruit=getItem(position);
        View view;
        ViewHolder viewHolder;
        if(convertView==null)
        {
            view= LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
            viewHolder=new ViewHolder();
            viewHolder.fruitName=view.findViewById(R.id.fruit_name);
            viewHolder.fruitImage=view.findViewById(R.id.fruit_image);
            view.setTag(viewHolder);//將ViewHolder存儲在View中
        }
       else
        {
            view=convertView;
            viewHolder= (ViewHolder) view.getTag();//重新獲取ViewHolder
        }

        viewHolder.fruitImage.setImageResource(fruit.getImageId());
        viewHolder.fruitName.setText(fruit.getName());
        return view;
    }
    class ViewHolder{
        ImageView fruitImage;
        TextView fruitName;
    }
}

 

單擊選項彈出消息提示信息

修改MainActivity.java代碼

package com.example.listviewtest;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
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<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruit();//初始化水果數據
        FruitAdapter adapter=new FruitAdapter(MainActivity.this,R.layout.fruit_item,fruitList);
        ListView listView=findViewById(R.id.listView);
        listView.setAdapter(adapter);
        //爲listView添加事件監聽器
        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();
            }
        });
    }
    private void initFruit()
    {
        for(int i=0;i<2;i++)
        {
            Fruit apple=new Fruit("Apple",R.drawable.apple_pic);
            fruitList.add(apple);
            Fruit banana=new Fruit("Banana",R.drawable.banana_pic);
            fruitList.add(banana);
            Fruit orange=new Fruit("Orange",R.drawable.orange_pic);
            fruitList.add(orange);
            Fruit watermelon=new Fruit("Watermelon",R.drawable.watermelon_pic);
            fruitList.add(watermelon);
            Fruit pear=new Fruit("Pear",R.drawable.pear_pic);
            fruitList.add(pear);
            Fruit grape=new Fruit("Grape",R.drawable.grape_pic);
            fruitList.add(grape);
            Fruit pineapple=new Fruit("Pineapple",R.drawable.pineapple_pic);
            fruitList.add(pineapple);
            Fruit strawberry=new Fruit("Strawberry",R.drawable.strawberry_pic);
            fruitList.add(strawberry);
            Fruit cherry=new Fruit("Cherry",R.drawable.cherry_pic);
            fruitList.add(cherry);
            Fruit mango=new Fruit("Mango",R.drawable.mango_pic);
            fruitList.add(mango);
        }
    }
}