论坛 › Java语言交流 › android编程6.4.1

alltolove 发表于 2017-10-16 06:24:40

android编程6.4.1

首先新建个项目，然后在mainactivity.java旁边新建个MyDatabaseHelper.java文件package com.example.xinwei.databasetest;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;

/**
* Created by xinwei on 2017/10/16.
*/

public class MyDatabaseHelper extends SQLiteOpenHelper {
    public static final String CREATE_BOOK = "create table book("
            +"id integer primary key autoincrement,"
            +"author text,"
            +"price real,"
            +"pages integer,"
            +"name text)";
    private Context mContext;
    public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
      super(context, name, factory, version);
      mContext=context;
    }

    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
      sqLiteDatabase.execSQL(CREATE_BOOK);
      Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
    }

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

    }
}

然后修改activity_main.xml文件<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.xinwei.databasetest.MainActivity">

    <Button
      android:id="@+id/create_database"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="create database"/>

</android.support.constraint.ConstraintLayout>

再修改mainactivity.java文件package com.example.xinwei.databasetest;

import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    private MyDatabaseHelper dbHelper;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,1);
      Button createDatabase = (Button)findViewById(R.id.create_database);
      createDatabase.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                dbHelper.getWritableDatabase();
            }
      });
    }
}

数据库创建就大功告成了，非常简单。

查看完整版本: android编程6.4.1