1、MVP模式demo的实现，效果下：
2、创建一个Fruit类：
package com.example.listview;
//Fruit类就是Model，表示应用程序中的数据对象。
public class Fruit {
private int imageId;
private String name;
private String price;
public Fruit(int imageId, String name, String price) {
this.imageId = imageId;
this.name = name;
this.price = price;
}
public int getImageId() {
return imageId;
}
public String getName() {
return name;
}
public String getPrice() {
return price;
}
}3、创建FruitAdapter适配器：
package com.example.listview;
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 FruitAdapter extends ArrayAdapter<Fruit> {
private int resourceId;
public FruitAdapter(Context context, int resourceId, List<Fruit> objects) {
super(context, resourceId, objects);
this.resourceId = resourceId;
}
@Override
public View getView(int position, View convertView, 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.fruitImage = view.findViewById(R.id.fruit_image);
viewHolder.fruitName = view.findViewById(R.id.fruit_name);
viewHolder.fruitPrice = view.findViewById(R.id.fruit_price);
view.setTag(viewHolder);
} else {
view = convertView;
viewHolder = (ViewHolder) view.getTag();
}
viewHolder.fruitImage.setImageResource(fruit.getImageId());
viewHolder.fruitName.setText(fruit.getName());
viewHolder.fruitPrice.setText("价格: " + fruit.getPrice() + "元/斤");
return view;
}
static class ViewHolder {
ImageView fruitImage;
TextView fruitName;
TextView fruitPrice;
}
}4、创建MainView接口，用于显示UI界面。
package com.example.listview;
import java.util.List;
//定义View，负责UI的展示和用户交互。
public interface MainView {
void displayFruits(List<Fruit> fruitList);
}
5、创建Presenter：
package com.example.listview;
import java.util.ArrayList;
import java.util.List;
//定义Presenter，用于处理业务逻辑和用户输入。
public class MainPresenter {
private MainView view;
private List<Fruit> fruitList;
public MainPresenter(MainView view) {
this.view = view;
fruitList = generateFruitData();
}
public void loadFruits() {
view.displayFruits(fruitList);
}
private List<Fruit> generateFruitData() {
List<Fruit> fruitList = new ArrayList<>();
fruitList.add(new Fruit(R.drawable.pineapple,"菠萝", "68"));
fruitList.add(new Fruit(R.drawable.strawberry,"草莓", "55"));
fruitList.add(new Fruit(R.drawable.orange,"橙子", "36"));
fruitList.add(new Fruit(R.drawable.longan,"桂圆", "78"));
fruitList.add(new Fruit(R.drawable.cantaloupe,"哈密瓜", "99"));
fruitList.add(new Fruit(R.drawable.dragon_fruit,"火龙果", "128"));
fruitList.add(new Fruit(R.drawable.kiwi, "猕猴桃", "90"));
fruitList.add(new Fruit(R.drawable.lemon,"柠檬", "56"));
fruitList.add(new Fruit(R.drawable.loquat, "枇杷", "81"));
fruitList.add(new Fruit(R.drawable.apple, "苹果", "160"));
fruitList.add(new Fruit(R.drawable.mandarin_orange, "砂糖桔", "150"));
fruitList.add(new Fruit(R.drawable.pomelo, "樱桃", "200"));
fruitList.add(new Fruit(R.drawable.tomato, "柚子", "62"));
fruitList.add(new Fruit(R.drawable.cherry, "西红柿", "60"));
fruitList.add(new Fruit(R.drawable.pineapple,"菠萝", "68"));
fruitList.add(new Fruit(R.drawable.strawberry,"草莓", "55"));
fruitList.add(new Fruit(R.drawable.orange,"橙子", "36"));
fruitList.add(new Fruit(R.drawable.longan,"桂圆", "78"));
fruitList.add(new Fruit(R.drawable.cantaloupe,"哈密瓜", "99"));
fruitList.add(new Fruit(R.drawable.dragon_fruit,"火龙果", "128"));
fruitList.add(new Fruit(R.drawable.kiwi, "猕猴桃", "90"));
fruitList.add(new Fruit(R.drawable.lemon,"柠檬", "56"));
fruitList.add(new Fruit(R.drawable.loquat, "枇杷", "81"));
fruitList.add(new Fruit(R.drawable.apple, "苹果", "160"));
fruitList.add(new Fruit(R.drawable.mandarin_orange, "砂糖桔", "150"));
fruitList.add(new Fruit(R.drawable.pomelo, "樱桃", "200"));
fruitList.add(new Fruit(R.drawable.tomato, "柚子", "62"));
fruitList.add(new Fruit(R.drawable.cherry, "西红柿", "60"));
return fruitList;
}
}
6、在MainActivity中实现MVP模式的业务逻辑：
package com.example.listview;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.util.List;
//Model：负责数据的管理和处理。
//View：负责UI的展示和用户交互。
//Presenter：连接Model和View，处理业务逻辑和用户输入。
//Presenter在加载数据后通过MainView接口回调通知View显示水果列表。
public class MainActivity extends AppCompatActivity implements MainView {
private ListView listView;
private FruitAdapter adapter;
private MainPresenter presenter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = findViewById(R.id.list_view);
presenter = new MainPresenter(this);
presenter.loadFruits();
}
@Override
public void displayFruits(List<Fruit> fruitList) {
adapter = new FruitAdapter(this, R.layout.item_fruit, fruitList);
listView.setAdapter(adapter);
listView.setOnItemClickListener((parent, view, position, id) -> {
Fruit fruit = fruitList.get(position);
showFruitDetails(fruit);
});
}
private void showFruitDetails(Fruit fruit) {
Toast.makeText(MainActivity.this, "名称: " + fruit.getName() + ", 价格: " + fruit.getPrice() + "元/斤", Toast.LENGTH_SHORT).show();
}
}7、activity_main.xml文件：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"/>
</RelativeLayout>8、item_fruit.xml文件：
<?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"
android:padding="16dp">
<ImageView
android:id="@+id/fruit_image"
android:layout_width="64dp"
android:layout_height="64dp"
android:scaleType="centerCrop"
android:src="@mipmap/ic_launcher" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical"
android:layout_marginStart="16dp">
<TextView
android:id="@+id/fruit_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:textStyle="bold"
android:text="水果名称" />
<TextView
android:id="@+id/fruit_price"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="14sp"
android:textColor="@android:color/darker_gray"
android:text="价格: " />
</LinearLayout>
</LinearLayout>
