android studio项目：数据存储和访问 建立SQLite数据库 实现增删查改

实验目的：
分别使用sqlite3工具和Android代码的方式建立SQLite数据库。在完成建立数据库的工作后，编程实现基本的数据库操作功能，包括数据的添加、删除和更新。

实验要求：
1.创建一个学生管理的应用，基本信息包含学生姓名，班级，学号。采用数据库存储这些信息。
2.应用应该至少包含信息录入和删除功能。
3.数据显示考虑采用ListView。

实验效果：

工程结构：

源代码：

DBAdapter.java

package com.example.shiyan6_sqlite;

import android.annotation.SuppressLint;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;

public class DBAdapter {

	private static final String DB_NAME = "student.db";
	private static final String DB_TABLE = "peopleinfo";
	private static final int DB_VERSION = 1;

	public static final String KEY_ID = "_id";
	public static final String KEY_NAME = "name";
	public static final String KEY_BANJI = "banji";
	public static final String KEY_XUEHAO = "xuehao";

	private SQLiteDatabase db;
	private final Context context;
	private DBOpenHelper dbOpenHelper;

	public DBAdapter(Context _context) {
		context = _context;
	}

	public void close() {
		if(db !=null)
		{
			db.close();
			db=null;
		}
	}

	public void open() throws SQLiteException {
		dbOpenHelper = new DBOpenHelper(context, DB_NAME, null, DB_VERSION);
		try {
			db = dbOpenHelper.getWritableDatabase();
		}
		catch (SQLiteException ex) {
			db = dbOpenHelper.getReadableDatabase();
		}
	}


	public long insert(People people) {
		ContentValues newValues = new ContentValues();
		newValues.put(KEY_NAME, people.Name);
		newValues.put(KEY_BANJI, people.Banji);
		newValues.put(KEY_XUEHAO, people.Xuehao);

		return db.insert(DB_TABLE, null, newValues);
	}


	public People[] queryAllData() {
		Cursor results =  db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_BANJI, KEY_XUEHAO},
				null, null, null, null, null);
		return ConvertToPeople(results);
	}

	public People[] queryOneData(long id) {
		Cursor results =  db.query(DB_TABLE, new String[] { KEY_ID, KEY_NAME, KEY_BANJI, KEY_XUEHAO},
				KEY_ID + "=" + id, null, null, null, null);
		return ConvertToPeople(results);
	}

	@SuppressLint("Range")
	private People[] ConvertToPeople(Cursor cursor){
		int resultCounts = cursor.getCount();
		if (resultCounts == 0 || !cursor.moveToFirst()){
			return null;
		}
		People[] peoples = new People[resultCounts];
		for (int i = 0 ; i 
People.java
 
package com.example.shiyan6_sqlite;

public class People {
	public int ID = -1;
	public String Name;
	public String Banji;
	public String Xuehao;

	@Override
	public String toString(){
		String result = "";
		result += "ID：" + this.ID + "，";
		result += "姓名：" + this.Name + "，";
		result += "班级：" + this.Banji + "， ";
		result += "学号：" + this.Xuehao;
		return result;
	}
}

 
MainActivity.java
 
package com.example.shiyan6_sqlite;

import androidx.appcompat.app.AppCompatActivity;

import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    EditText e_xm,e_nl,e_sg,e_id;
    TextView t_1;
    Button b_add,b_allsee,b_clearsee,b_alldel,b_delid,b_seeid,b_updid;
    DBAdapter dbAdapter;
    SQLiteDatabase db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        e_xm=findViewById(R.id.e_xm);
        e_nl=findViewById(R.id.e_nl);
        e_sg=findViewById(R.id.e_sg);
        b_add=findViewById(R.id.b_add);
        b_allsee=findViewById(R.id.b_allsee);
        b_clearsee=findViewById(R.id.b_clearall);
        b_alldel=findViewById(R.id.b_delall);
        b_delid=findViewById(R.id.b_delid);
        b_seeid=findViewById(R.id.b_seeid);
        b_updid=findViewById(R.id.b_updid);
        e_id=findViewById(R.id.e_id);
        t_1=findViewById(R.id.t_1);
        dbAdapter=new DBAdapter(this);
        dbAdapter.open();


        b_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                People t=new People();
                t.Name=e_xm.getText().toString();
                t.Banji=e_nl.getText().toString();
                t.Xuehao=e_sg.getText().toString();
                long colunm=dbAdapter.insert(t);
                if (colunm == -1 ){
                    t_1.setText("添加过程错误！");
                } else {
                    t_1.setText("成功添加数据，ID："+String.valueOf(colunm));
                }
            }
        });

        b_allsee.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                People [] peoples =dbAdapter.queryAllData();
                if (peoples == null){
                    t_1.setText("数据库中没有数据");
                    return;
                }
                String t="数据库:n";
                for(int i=0;i0?"成功":"失败");
                t_1.setText(msg);
            }
        });

        b_seeid.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int id=Integer.parseInt(e_id.getText().toString());
                People people[]=dbAdapter.queryOneData(id);
                if(people==null){
                    t_1.setText("Id为"+id+"的记录不存在！");
                }
                else{
                    t_1.setText("查询成功：n"+people[0].toString());
                }
            }
        });

        b_updid.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int id=Integer.parseInt(e_id.getText().toString());
                People t=new People();
                t.Name=e_xm.getText().toString();
                t.Banji=e_nl.getText().toString();
                t.Xuehao=e_sg.getText().toString();
                long n=dbAdapter.updateOneData(id,t);
                if (n<0){
                    t_1.setText("更新过程错误！");
                } else {
                    t_1.setText("成功更新数据，"+String.valueOf(n)+"条");
                }
            }
        });
    }

    @Override
    protected void onStop() {
        super.onStop();
        dbAdapter.close();
    }
}