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  • sqlite创建数据库并创建一个表

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.example.cunli.sqllite001.MainActivity">
    
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="新建数据库并创建一个表"
            android:gravity="center"
            android:onClick="openDb"/>
    </RelativeLayout>
    package com.example.cunli.sqllite001;
    
    import android.content.Context;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    
    public class MainActivity extends AppCompatActivity {
    SQLiteDatabase sqLiteDatabase;
        private Context context = MainActivity.this;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
        }
    
        public void openDb(View view){
    //以可读写的方式打开或创建一个数据库
        //使用MyOpenHelper打开数据库
            MyOpenHelper myOpenHelper = new MyOpenHelper(context,"school",null,1);
            //使用getReadableDatabase()得到SQLiteDatabase一个对象
            sqLiteDatabase = myOpenHelper.getReadableDatabase();
    
            //插入一条数据
            String sql = "insert into Students (student_name,mobile,gender) values (?,?,?)";
            sqLiteDatabase.execSQL(sql,new Object[]{"zhangsan","12345678900",Boolean.valueOf(false)});
            //关闭数据库
            sqLiteDatabase.close();
        }
        class MyOpenHelper extends SQLiteOpenHelper{
            public MyOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
                super(context, name, factory, version);
            }
    //只会在第一次创建数据库的时候调用
            @Override
            public void onCreate(SQLiteDatabase db) {
                String createSQL = "CREATE TABLE IF NOT EXISTS Students (_id INTEGER NOT NULL,student_name CHAR(20) NOT NULL,mobile CHAR(20),gender BOOLEAN,PRIMARY KEY(_id))";
                db.execSQL(createSQL);
    
            }
    //这里不需要升级,保留空方法即可
            @Override
            public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    
            }
        }
    }
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  • 原文地址:https://www.cnblogs.com/thankyouGod/p/6288815.html
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