Android ListView与适配器

╰半夏微凉° 2022-09-25 00:25 183阅读 0赞

**练习：实现如下图新闻列表，**

**并且添加点赞，且点击点赞、点攒数增加，**

**点击图片显示已点击了图片。**

**![Center][]**

**布局：**

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/title"
        android:gravity="center"
        android:text="标题"
        android:layout_alignParentTop="true"
        android:layout_toEndOf="@+id/from"
        android:layout_marginStart="96dp"
        android:layout_marginTop="19dp" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:id="@+id/from"
        android:text="未来网"
        android:layout_alignBaseline="@+id/pubData"
        android:layout_alignBottom="@+id/pubData"
        android:layout_alignParentStart="true" />
        <ImageView
            android:layout_width="60dp"
            android:layout_height="60dp"
            android:src="@mipmap/ic_launcher"
            android:id="@+id/iv"
            android:scaleType="centerCrop"
            android:layout_alignParentTop="true"
            android:layout_alignParentEnd="true" />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/pubData"
            android:text="今天"
            android:layout_below="@+id/iv"
            android:layout_alignStart="@+id/iv"
            android:layout_marginStart="14dp" />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="点赞"
            android:id="@+id/good"
            android:layout_alignTop="@+id/goodcount"
            android:layout_alignStart="@+id/title" />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1000"
            android:id="@+id/goodcount"
            android:layout_below="@+id/iv"
            android:layout_toEndOf="@+id/title" />
    </RelativeLayout>

**class文件：**

package com.example.administrator.jreduch05.entity;
    
    /**
     * Created by Administrator on 2016/8/3.
     */
    public class News {
    
        private String title;
        private String pubData;
        private String newsId;
        private int img;
        private String from;
        private  String good;
        private int goodcount;
        public News(){}
    
        public News(String title, String pubData, String newsId, int img, String from, String good, int goodcount) {
            this.title = title;
            this.pubData = pubData;
            this.newsId = newsId;
            this.img = img;
            this.from = from;
            this.good = good;
            this.goodcount = goodcount;
        }
    
        public String getTitle() {
            return title;
        }
    
        public void setTitle(String title) {
            this.title = title;
        }
    
        public String getPubData() {
            return pubData;
        }
    
        public void setPubData(String pubData) {
            this.pubData = pubData;
        }
    
        public String getNewsId() {
            return newsId;
        }
    
        public void setNewsId(String newsId) {
            this.newsId = newsId;
        }
    
        public int getImg() {
            return img;
        }
    
        public void setImg(int img) {
            this.img = img;
        }
    
        public String getFrom() {
            return from;
        }
    
        public void setFrom(String from) {
            this.from = from;
        }
    
        public String getGood() {
            return good;
        }
    
        public void setGood(String good) {
            this.good = good;
        }
    
        public int getGoodcount() {
            return goodcount;
        }
    
        public void setGoodcount(int goodcount) {
            this.goodcount = goodcount;
        }
    }

**适配器：**

package com.example.administrator.jreduch05.adapter;
    
    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.ImageView;
    import android.widget.TextView;
    import android.widget.Toast;
    
    import com.example.administrator.jreduch05.R;
    import com.example.administrator.jreduch05.entity.News;
    
    import java.util.List;
    
    /**
     * Created by Administrator on 2016/8/3.
     */
    public class MyListAdapter extends BaseAdapter{
    
        private List<News> myData;
        private Context context;
    
        public MyListAdapter(Context context,List<News>myData){
            this.myData=myData;
            this.context=context;
        }
        @Override
        public int getCount() {
            return myData.size();
        }
    
        @Override
        public Object getItem(int position) {
            return myData.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return 0;
        }
    
        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            final ViewHolder vh;
            if(convertView==null){
                vh=new ViewHolder();
                convertView=LayoutInflater.from(context).inflate(R.layout.list_layout_base,null);
                vh.title=  (TextView) convertView.findViewById(R.id.title);
                vh.pubData=  (TextView) convertView.findViewById(R.id.pubData);
                vh.from=  (TextView) convertView.findViewById(R.id.from);
                vh.img  =(ImageView) convertView.findViewById(R.id.iv);
                vh.good  =(TextView) convertView.findViewById(R.id.good);
    
                convertView.setTag(vh);
            }else{
                vh=(ViewHolder)convertView.getTag();
            }
            final News ns=myData.get(position);
            vh.good.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int count=Integer.parseInt(vh.goodCount.getText().toString());
                    vh.goodCount.setText(count+1+"");
                    ns.setGoodcount(count);
                    //vh.goodCount.setTextColor();
                }
            });
            vh.goodCount  =(TextView) convertView.findViewById(R.id.goodcount);
            vh.img.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(context,"点击了图片"+position,
                            Toast.LENGTH_SHORT).show();
                }
            });
            vh.title.setText(ns.getTitle());
            vh.pubData.setText(ns.getPubData());
            vh.from.setText(ns.getFrom());
            vh.img.setImageResource(ns.getImg());
            vh.good.setText(ns.getGood());
            vh.goodCount.setText(ns.getGoodcount()+"");
    
          return convertView;
        }
    
        public class ViewHolder{
            TextView title;
            TextView pubData;
            TextView from;
            ImageView img;
            TextView good;
            TextView goodCount;
        }
    }

**Activity主文件：**

package com.example.administrator.jreduch05;
    
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.widget.ListView;
    
    import com.example.administrator.jreduch05.adapter.MyListAdapter;
    import com.example.administrator.jreduch05.entity.News;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class List3Activity extends AppCompatActivity {
        private ListView lv;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_list3);
            lv=(ListView)findViewById(R.id.lv);
    
            List <News>list=new ArrayList();
            News ns=new News("新闻1","刚刚","001",R.mipmap.dianzan,"新浪网","点赞",10);
            list.add(ns);
    
            ns=new News("新闻2","今天","002",R.mipmap.dianzan,"未来网","点赞",11);
            list.add(ns);
    
            ns=new News("新闻2","今天","003",R.mipmap.dianzan,"搜狐网","点赞",12);
            list.add(ns);
    
            ns=new News("新闻3","今天","004",R.mipmap.dianzan,"网易网","点赞",13);
            list.add(ns);
    
            ns=new News("新闻4","昨天","005",R.mipmap.dianzan,"天涯网","点赞",14);
            list.add(ns);
    
            lv.setAdapter(new MyListAdapter(this,list));
        }
    }

[Center]: /images/20220719/7398ead6caca4adca6b8c78d8e2b6f15.png