基于AndroidStudio内置数据库SQLite，构建简单实现数据库增删改查功能APP

Android提供了SQLiteDatabase代表一个数据库（底层就是一个数据库文件）,一旦应用程序获得了代表指定数据库的SQLiteDatabase对象，接下来可通过SQLiteDatabase对象来管理、操作数据库。

Android中使用SQLite数据库进行开发时，主要利用SQL语句来进行基本功能实现。掌握如下增删改查语句更利于学习。

创建表create table tableName(id integer primary key autoincrement , name , text , number text);

删除表 drop table if exists tableName;

增加一条数据：insert into tableName values(“小明”,”111”);

删除一条数据：delete from tableName where name=”小明”;

修改一条数据：update tableName set name=”小红” where name=”小明”;

查询一条数据:select*from tableName where name=”小明”;

首页

效果图：

MainActivity.java

package com.example.sqlite_foundation;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

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

    public void insertData(View view){
        //进行跳转
        Intent intent = new Intent(this,insertActivity.class);
        startActivity(intent);


    }

    public void deleteData(View view){

        Intent intent = new Intent(this,DeleteActivity.class);
        startActivity(intent);

    }

    public void updateData(View view){

        Intent intent = new Intent(this,UpdateActivity.class);
        startActivity(intent);
    }

    public void queryData(View view){

        Intent intent = new Intent(this,QueryActivity.class);
        startActivity(intent);
    }
}

activity_main.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"
    android:orientation="vertical"
    android:gravity="center"
    android:background="@drawable/back"
    android:scaleType="matrix"
    >

   <Button
       android:layout_width="300dp"
       android:layout_height="60dp"
       android:onClick="insertData"
       android:text="添加数据"
       android:textSize="20sp"
       android:textStyle="bold"
       android:layout_gravity="center"
       android:background="@color/yellow"/>

    <Button
        android:layout_width="300dp"
        android:layout_height="60dp"
        android:onClick="deleteData"
        android:text="删除数据"
        android:textSize="20sp"
        android:textStyle="bold"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:background="@color/yellow"/>

    <Button
        android:layout_width="300dp"
        android:layout_height="60dp"
        android:onClick="updateData"
        android:text="修改数据"
        android:textSize="20sp"
        android:textStyle="bold"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:background="@color/yellow"/>

    <Button
        android:layout_width="300dp"
        android:layout_height="60dp"
        android:onClick="queryData"
        android:text="查询数据"
        android:textSize="20sp"
        android:textStyle="bold"
        android:layout_gravity="center"
        android:layout_marginTop="20dp"
        android:background="@color/yellow"/>


</LinearLayout>

数据库创建

MySQLiteOpenHerper.java

package com.example.sqlite_foundation;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.Nullable;

import com.example.sqlite_foundation.bean.Student;

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

public class MySQLiteOpenHelper extends SQLiteOpenHelper {

    private static final String DB_NAME="mySQLite.db";
    private static final String TABLE_NAME_STUDENT="student";

    //SQL语句准备
    private static final String CREATE_TABLE_SQL = "create table " + TABLE_NAME_STUDENT + " (id integer primary key autoincrement,name text,number text,gender text,score text);";
    //定死参数
    public MySQLiteOpenHelper(Context context){
        super(context,DB_NAME,null,1);
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        //执行SQL语句
        sqLiteDatabase.execSQL(CREATE_TABLE_SQL);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }

    //插入数据方法
    public long insertData(Student student){
        //得到一个可写数据库
        SQLiteDatabase db = getWritableDatabase();

        ContentValues values = new ContentValues();

        //传值准备数据
        values.put("name",student.getName());
        values.put("number",student.getNumber());
        values.put("gender",student.getGender());
        values.put("score",student.getScore());

        //把数据插入到数据库中
        //返回当前行的id，若为-1则数据插入失败
        return db.insert(TABLE_NAME_STUDENT,null,values);

    }

    //按姓名删除数据方法
    public int deleteFromDbByName(String name){
        SQLiteDatabase db = getWritableDatabase();

        return db.delete(TABLE_NAME_STUDENT,"name like ?",new String[]{name});
    }

    //修改数据方法
    public int updateData(Student student){
        SQLiteDatabase db = getWritableDatabase();

        ContentValues values = new ContentValues();

        //传值准备数据
        values.put("name",student.getName());
        values.put("number",student.getNumber());
        values.put("gender",student.getGender());
        values.put