花生_TL007

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Android之SQLite数据库及SQLiteStudio工具的使用，全网最新_android sqlite

作者：花生_TL007 | 2024-05-28 07:29:17

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android sqlite

主页面

点击创建数据库，Log打印日志

创建数据库

点击插入数据（SQLiteStudio中显示数据）

学生表

点击删除数据：（SQLiteStudio显示数据和Android中Log打印日志）

删除数据

更新数据：（SQLiteStudio显示数据和AndroidStudio中Log打印日志）

更新数据

查询数据：（AndroidStudio中Log打印数据）

查询数据

（六）代码

===============================================================

MainActivity.java

public class MainActivity extends Activity {

private DatabaseHelper databaseHelper; //用于创建帮助器对象

private SQLiteDatabase db; //用于创建数据库对象

private static final String name = “mydatabase.db”; //数据库名称

private static final int version = 1; //数据库版本

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

SQLiteStudioService.instance().start(this);

}

//创建数据库

public void createDatabase(View view) {

databaseHelper = new DatabaseHelper(this, name, null, version);

db = databaseHelper.getWritableDatabase();

}

//向数据库中添加数据

public void Insert(View view) {

//向学生表中添加数据

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230001, “张三”, 17, 75});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230002, “李四”, 20, 79});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230003, “Mark”, 18, 99});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230004, “Mary”, 22, 89});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230005, “王五”, 16, 83});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230006, “Jack”, 19, 91});

db.execSQL(“insert into student(id, name, age, grade) values(?, ?, ?, ?)”, new Object[]{1230007, “李华”, 21, 85});

Log.d(“MainActivity”, “信息插入成功！”);

}

//删除数据库中的数据

public void Delete(View view) {

//删除李华信息

db.execSQL(“delete from student where name = ?”, new Object[]{“Jack”});

Log.d(“MainActivity”, “Jack信息被删除！”);

}

//修改数据库中的数据

public void Update(View view) {

//将张三的学号改为1111111

db.execSQL(“update student set id = 1111111 where name=‘张三’”);

Log.d(“MainActivity”, “张三数据信息更新成功！”);

}

//查询数据库中的数据

public void Select(View view) {

//查询数据库中学生的信息

Cursor cursor = db.rawQuery(“select * from student”, null);

while (cursor.moveToNext()) {

//用cursor.getColumnIndex获得列

Integer id = cursor.getInt(cursor.getColumnIndex(“id”));

String name = cursor.getString(cursor.getColumnIndex(“name”));

Integer age = cursor.getInt(cursor.getColumnIndex(“age”));

float grade = cursor.getFloat(cursor.getColumnIndex(“grade”));

Log.d(“MainActivity”, “[学号：” + id + “, 名字：” + name + “, 年龄：” + age + “, 成绩：” + grade + ‘]’);

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android=“http://schemas.android.com/apk/res/android”

xmlns:tools=“http://schemas.android.com/tools”

android:layout_width=“match_parent”

android:layout_height=“match_parent”

tools:context=“.MainActivity”

android:orientation=“vertical”>

<Button

android:layout_width=“wrap_content”