[移动开发]Android listview和adapter

ListView 和 Adapter的关系: 就是将ListView绑定的界面中的数据与adapter相适配

MainActivity.java

package com.example.listviewtest;

import androidx.appcompat.app.AppCompatActivity;

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

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

public class MainActivity extends AppCompatActivity {
    private Bean bean;
    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 = new Bean();
            bean.setName("zjx"+i);
            data.add(bean);
        }
        ListView listView = findViewById(R.id.lv);
        listView.setAdapter(new MyAdapter(data,this));
    }
}

MyAdapter.java

package com.example.listviewtest;
/*
 *todo author:张建新
 *todo @since :2021/12/13/0013
 *todo 作用:
 */

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;

public class MyAdapter extends BaseAdapter {

    private List<Bean> data = new ArrayList<>();
    private Context context;

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


    @Override
    public int getCount() {
        return data.size();
    }

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

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView==null){
            convertView = LayoutInflater.from(context).inflate(R.layout.list_view,parent,false);
        }
        TextView textView = convertView.findViewById(R.id.tv);
        textView.setText(data.get(position).getName());
        return convertView;
    }
}

一个固定的写java的模式 javaBean

Bean.java

package com.example.listviewtest;
/*
 *todo author:张建新
 *todo @since :2021/12/13/0013
 *todo 作用:
 */

public class Bean {
    public String getName() {
        return name;
    }

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

    private String name ;
}

list_view.xml

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

</LinearLayout>

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:id="@+id/lv"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"/>

</LinearLayout>