Android 数据库管理— — —创建数据库

<?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" >

    <Button        android:id="@+id/create_database"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="创建数据库"        android:layout_marginTop="10dp"        /></LinearLayout>

package com.example.databasetest;

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

/** * Created by Administrator on 2016/3/4. */public class DatabaseHelper 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;

    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL(CREATE_BOOK);        Toast.makeText(mContext,"创建数据库成功",Toast.LENGTH_SHORT).show();    }

    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public DatabaseHelper(Context context, String name, CursorFactory factory, int version) {            super(context, name, factory, version);            mContext = context;    }}

package com.example.datebasetest;

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

public class MainActivity extends AppCompatActivity {

    private Button btn;    private DatabaseHelper dbHelper;

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

        btn = (Button)findViewById(R.id.create_database);        dbHelper = new DatabaseHelper(this,"BookStore",null,1);

        btn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                dbHelper.getWritableDatabase();            }        });    }}