Adapter使用实例

ゞ浴缸里的玫瑰 2022-09-25 13:24 175阅读 0赞

**第一个实例**

1.activity\_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/LinearLayout1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.zj.myc.MainActivity">
    
    
        <ListView
            android:id="@+id/ListView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
    
        </ListView>
    </LinearLayout>

2.item\_adapter.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/LinearLayout2"
        >
    
    
        <TextView
            android:id="@+id/TextView2"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text=""
            />
    
    </LinearLayout>

3.MainAdepter.java

package com.zj.myc;
    
    import android.app.Activity;
    import android.content.Context;
    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /**
     * Created by Administrator on 2016-09-07.
     */
    public class MainAdepter extends BaseAdapter {
            private Context context; //上下文
    
        private List<String > list = new ArrayList<>();
    
        public MainAdepter(Context context, List<String> list) {
            this.context = context;
            this.list = list;
        }
    
    
    
        @Override
        public int getCount() {
            return list.size();
        }
    
        @Override
        public Object getItem(int position) {
            return list.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return position;
        }
    
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHodler hodler =null;
            if(convertView==null ){
                LayoutInflater inflater = LayoutInflater.from(context);
                convertView  = inflater.inflate(R.layout.item_adapter,null);
                hodler = new ViewHodler();
                hodler.text = (TextView)convertView.findViewById(R.id.TextView2);
                convertView.setTag(hodler);
            } else{
                hodler = (ViewHodler) convertView.getTag();
            }
            hodler.text.setText(list.get(position));
    
            return convertView;
        }
    
    
        class ViewHodler{
            public TextView text;
        }
    }

4.MainActivity.java

package com.zj.myc;
    
    import android.app.Activity;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ListView;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class MainActivity extends Activity {
    
        private ListView listView ;
        private List<String> list = new ArrayList<>();
        private MainAdepter mainAdepter ;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            init();
            initDate();
            mainAdepter = new MainAdepter(MainActivity.this,list);
            //将listView关联适配器MainAdepter对象
            listView.setAdapter(mainAdepter);
    
            /***
             * 视图里面的列表选项点击事件
             */
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    Log.v("===",position + "==aaa=="+list.get(position));
                }
            });
    
    
        }
    
    
        /**
         * 初始化UI控件
         */
        private void init() {
            listView = (ListView) findViewById(R.id.ListView1);
        }
    
        // 模拟数据
        private void initDate() {
            for (int i = 0; i<5; i++){
                list.add("列表使用"+i);
            }
        }
    }

运行结果 ![Center][]

第二个实例

1.layout\\activity\_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/LinearLayout1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.zj.myc_qq.MainActivity">
    
    
        <ListView
            android:id="@+id/ListView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            >
    
        </ListView>
    </LinearLayout>

2.item\_adapter.xml

3.MainAdepter.java

package com.zj.myc_qq;
    
    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    
    /**
     * Created by Administrator on 2016-09-07.
     */
    public class MainAdepter extends BaseAdapter {
    
        private Context context; //上下文
        private List<Map<String, Object>> list = new ArrayList<>(); //数据集合
    
        /**构造器*/
        public MainAdepter(Context context, List<Map<String, Object>> list) {
            this.context = context;
            this.list = list;
        }
    
    
        @Override
        public int getCount() {
            return list.size();
        }
    
        @Override
        public Object getItem(int position) {
            return list.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return position;
        }
    
        /**
         * getView返回新的视图，并显示在ListView上
         * @param position 适配数据的位置（索引）
         * @param convertView 复用旧视图
         * @param parent 相关联的父视图
         * @return 由适配器创建的视图（可为不同类型）
         */
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHodler holder;
            //第一次加载
            if (null == convertView) {
                holder = new ViewHodler();
                LayoutInflater inflater = LayoutInflater.from(context);
                convertView = inflater.inflate(R.layout.item_adapter, null);
                //UI实例化
                holder.title = (TextView) convertView.findViewById(R.id.title);
                holder.info = (TextView) convertView.findViewById(R.id.info);
                holder.time = (TextView) convertView.findViewById(R.id.time);
                //设置标记,并缓存旧数据
                convertView.setTag(holder);
            } else {
                holder = (ViewHodler) convertView.getTag();
            }
            //赋值
            holder.title.setText(list.get(position).get("title").toString());
            holder.info.setText(list.get(position).get("info").toString());
            holder.time.setText(list.get(position).get("time").toString());
    
            return convertView;
        }
    
    
        /**
         * 视图容器的内部类
         */
        public class ViewHodler {
            public TextView text;
            public TextView title;
            public TextView info;
            public TextView time;
        }
    }

4.MainActivity.java

package com.zj.myc_qq;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ListView;
    
    import java.util.ArrayList;
    import java.util.Calendar;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Locale;
    import java.util.Map;
    
    public class MainActivity extends Activity {
        //控件
        private ListView listView;
        //数据集合
        private List<Map<String, Object>> list = new ArrayList<>();
        private MainAdepter mainAdepter;//将另一个类引用用到本类
        // 日期
        Calendar calendar = Calendar.getInstance(Locale.CHINA);
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            init();
            getData();
            mainAdepter = new MainAdepter(MainActivity.this, list);
            //将listView关联适配器MainAdepter对象
            listView.setAdapter(mainAdepter);
    
            /***
             * 视图里面的列表选项点击事件
             */
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    Log.v("===", position + "==aaa==" + list.get(position));
                }
            });
    
        }
    
        /**
         * 初始化UI控件
         */
        private void init() {
            listView = (ListView) findViewById(R.id.ListView1);
        }
    
        // 模拟数据
        public List<Map<String, Object>> getData() {
    
            for (int i = 0; i < 4; i++) {
                Map<String, Object> map = new HashMap<String, Object>();
                map.put("imag", R.drawable.ic_launcher);
                map.put("title", "item=" + i);
                map.put("info", "加油啊=" + i);
                map.put("time", calendar.get(Calendar.YEAR) + "年" + calendar.get(Calendar.MONTH) + "月" + calendar.get(Calendar.DAY_OF_MONTH) + "日");
                list.add(map);
    
            }
            return list;
        }
    }

运行结果 ![Center 1][]

[Center]: /images/20220717/b748400439404b138f945ba0acc7c3c7.png
[Center 1]: /images/20220717/1d3664b0b66f44faa63ab6e88102c4d7.png