[移动开发]Android开发----ListView

ListView

主要用于显示一个垂直滚动的数据集合

详细教程:
https://www.jianshu.com/p/0eef3be8cd8b

示例实操

activity_main.xml
在里边建一个listview

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


</LinearLayout>

再创建一个list_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        android:orientation="vertical"
        xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView android:layout_width="wrap_content" android:layout_height="wrap_content"
                android:id="@+id/tv" android:textSize="30sp"
    />
</LinearLayout>

里边放着textview
新建实体类存放信息
bean.java

package com.example.mylistview;

public class Bean {
    String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

MainActivity.java

package com.example.mylistview;

import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

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

public class MainActivity extends AppCompatActivity {
    private List<Bean> data=new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        for (int i=0;i<100;i++){
            Bean bean=new Bean();
            bean.setName("博客之星"+i);
            data.add(bean);
        }
        ListView listView=findViewById(R.id.list);
        listView.setAdapter(new MyAdapter(data,this));
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, android.view.View view, int i, long l) {
                Log.e("碰磕","item"+i+"点击成功");
            }
        });
    }
}

MyAdapter.java
用于继承baseAdapter

package com.example.mylistview;

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.List;

public class MyAdapter extends BaseAdapter {
    private List<Bean> data;
    private Context context;
    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder viewHolder;
        if(view==null) {
            viewHolder=new ViewHolder();
            view = LayoutInflater.from(context).inflate(R.layout.list_view, viewGroup, false);
            viewHolder.textView=view.findViewById(R.id.tv);
            view.setTag(viewHolder);
        }else {
            viewHolder=(ViewHolder) view.getTag();
        }
//        TextView textView=view. findViewById(R.id.tv);
//        textView.setText(data.get(i).getName());
        viewHolder.textView.setText(data.get(i).getName());
        return view;
    }

    private final class ViewHolder{
        TextView textView;

    }

    public MyAdapter(List<Bean> data, Context context) {
        this.data = data;
        this.context = context;
    }
}

效果图

点击9和11控制台会打印相对应的操作,因为添加了item点击事件

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, android.view.View view, int i, long l) {
                Log.e("碰磕","item"+i+"点击成功");
            }
        });

ListView的练习测试就完成了!!!