Android 之 数据存储与访问 —— 初见 SQLite 数据库

import android.content.ContentValues
import android.content.Context
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
 
class DatabaseHelper(context: Context) : SQLiteOpenHelper(context, "Student.db", null, 1) {
 
    override fun onCreate(db: SQLiteDatabase) {
        val createTableStatement = "CREATE TABLE Student (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, AGE INTEGER)"
        db.execSQL(createTableStatement)
    }
 
    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
        // 这里处理数据库升级的逻辑
    }
 
    fun insertData(name: String, age: Int) {
        val db = this.writableDatabase
        val contentValues = ContentValues()
        contentValues.put("NAME", name)
        contentValues.put("AGE", age)
        db.insert("Student", null, contentValues)
        db.close()
    }
 
    fun readData(): MutableList<Pair<String, Int>> {
        val data = mutableListOf<Pair<String, Int>>()
        val db = this.readableDatabase
        val selectQuery = "SELECT * FROM Student"
        val cursor = db.rawQuery(selectQuery, null)
        if (cursor.moveToFirst()) {
            do {
                val name = cursor.getString(cursor.getColumnIndex("NAME"))
                val age = cursor.getInt(cursor.getColumnIndex("AGE"))
                data.add(Pair(name, age))
            } while (cursor.moveToNext())
        }
        cursor.close()
        db.close()
        return data
    }
}

这段代码定义了一个DatabaseHelper类，它继承自SQLiteOpenHelper。在onCreate方法中创建了一个名为Student的表，并定义了两个字段：ID和NAME以及AGE。还提供了insertData和readData方法，分别用于插入和读取数据。这个类可以被用来管理学生数据，展示了如何在Android中使用SQLite数据库的基本用法。