2024/2/22

我们的一条数据项目包括，收入（指出）、说明、日期、金额四项，所以我们要自定义一个适配器

这里适配器的一个列表的各个单位的类型是一个打包好的类的类型。这个类也是自己创建的

package com.example.myapplication;

public class costList {
    private String _id;
    private String se;
    private String Title;
    private String Date;
    private String Money;

    public String getMoney() {
        return Money;
    }

    public void setMoney(String money) {
        Money = money;
    }

    public String getDate() {
        return Date;
    }

    public void setDate(String date) {
        Date = date;
    }

    public String getTitle() {
        return Title;
    }

    public void setTitle(String title) {
        Title = title;
    }

    public String get_id() {
        return _id;
    }

    public void set_id(String _id) {
        this._id = _id;
    }

    public String getSe() {
        return se;
    }

    public void setSe(String se) {
        this.se = se;
    }
}

package com.example.myapplication;

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 ListAdapter extends BaseAdapter {
    List<costList> mList;


    public ListAdapter(List<costList>list)
    {
        mList=list;
    }
    @Override
    public int getCount() {
        return mList.size();
    }

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view=mLayoutInflater.inflate(R.layout.list_item,null);
        //取出数据赋值
        costList item=mList.get(position);
        TextView tv_spin=view.findViewById(R.id.tv_spin);
        TextView tv_title=view.findViewById(R.id.tv_title);
        TextView tv_date=view.findViewById(R.id.tv_date);
        TextView tv_money=view.findViewById(R.id.tv_money);
        //绑定
        tv_spin.setText(mList.get(position).getSe());
        tv_title.setText(mList.get(position).getTitle());
        tv_date.setText(mList.get(position).getDate());
        tv_money.setText(mList.get(position).getMoney());
        return view;
    }
    private List<costList>getmList;
    private LayoutInflater mLayoutInflater;

    public ListAdapter(Context context, List<costList>list)
    {
        mList=list;
        //通过外部传来的Context初始化LayoutInflater对象
        mLayoutInflater=LayoutInflater.from(context);
    }
}

package com.example.myapplication;

import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private DBHelper helper;
    private  ListView listView;
    private List<costList>list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initData();
    }
    @SuppressLint("Range")
    private void initData() {
        list=new ArrayList<>();
        SQLiteDatabase db=helper.getReadableDatabase();
        Cursor cursor=db.query("account2",null,null,null,null,
                null,null);
        while (cursor.moveToNext()){
            costList clist=new costList();//构造实例
            clist.setSe(cursor.getString(cursor.getColumnIndex("Se")));
            clist.set_id(cursor.getString(cursor.getColumnIndex("_id")));
            clist.setTitle(cursor.getString(cursor.getColumnIndex("Title")));
            clist.setDate(cursor.getString(cursor.getColumnIndex("Date")));
            clist.setMoney(cursor.getString(cursor.getColumnIndex("Money")));
            list.add(clist);
        }
        //绑定适配器
        listView.setAdapter(new ListAdapter(this,list));
        db.close();
    }
    private void initView() {
        helper=new DBHelper(MainActivity.this);
        listView = findViewById(R.id.list_view);
    }
    public void addAccount(View view){//跳转
        Intent intent=new Intent(MainActivity.this,new_cost.class);
        //noinspection deprecation
        startActivityForResult(intent,1);
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data)//返回会刷新页面 
{
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==1&&resultCode==1)
        {
            iniView();
        }
    }
}

最后再在我们的页面操作了Java程序中按照我们打包好的列表进行适配得到我们需要的页面。