android编程6.4.1

alltolove

首先新建个项目，然后在mainactivity.java旁边新建个MyDatabaseHelper.java文件

1. package com.example.xinwei.databasetest;
   
2. 
   
3. import android.content.Context;
   
4. import android.database.sqlite.SQLiteDatabase;
   
5. import android.database.sqlite.SQLiteOpenHelper;
   
6. import android.widget.Toast;
   
7. 
   
8. /**
   
9. * Created by xinwei on 2017/10/16.
   
10. */
    
11. 
    
12. public class MyDatabaseHelper extends SQLiteOpenHelper {
    
13.     public static final String CREATE_BOOK = "create table book("
    
14.             +"id integer primary key autoincrement,"
    
15.             +"author text,"
    
16.             +"price real,"
    
17.             +"pages integer,"
    
18.             +"name text)";
    
19.     private Context mContext;
    
20.     public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
    
21.         super(context, name, factory, version);
    
22.         mContext=context;
    
23.     }
    
24. 
    
25.     @Override
    
26.     public void onCreate(SQLiteDatabase sqLiteDatabase) {
    
27.         sqLiteDatabase.execSQL(CREATE_BOOK);
    
28.         Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
    
29.     }
    
30. 
    
31.     @Override
    
32.     public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
    
33. 
    
34.     }
    
35. }
    

复制代码

然后修改activity_main.xml文件

1. <?xml version="1.0" encoding="utf-8"?>
   
2. <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
   
3.     xmlns:app="http://schemas.android.com/apk/res-auto"
   
4.     xmlns:tools="http://schemas.android.com/tools"
   
5.     android:layout_width="match_parent"
   
6.     android:layout_height="match_parent"
   
7.     tools:context="com.example.xinwei.databasetest.MainActivity">
   
8. 
   
9.     <Button
   
10.         android:id="@+id/create_database"
    
11.         android:layout_width="match_parent"
    
12.         android:layout_height="wrap_content"
    
13.         android:text="create database"/>
    
14. 
    
15. </android.support.constraint.ConstraintLayout>
    

复制代码

再修改mainactivity.java文件

1. package com.example.xinwei.databasetest;
   
2. 
   
3. import android.support.v7.app.AlertDialog;
   
4. import android.support.v7.app.AppCompatActivity;
   
5. import android.os.Bundle;
   
6. import android.view.View;
   
7. import android.widget.Button;
   
8. 
   
9. public class MainActivity extends AppCompatActivity {
   
10.     private MyDatabaseHelper dbHelper;
    
11.     @Override
    
12.     protected void onCreate(Bundle savedInstanceState) {
    
13.         super.onCreate(savedInstanceState);
    
14.         setContentView(R.layout.activity_main);
    
15.         dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,1);
    
16.         Button createDatabase = (Button)findViewById(R.id.create_database);
    
17.         createDatabase.setOnClickListener(new View.OnClickListener() {
    
18.             @Override
    
19.             public void onClick(View view) {
    
20.                 dbHelper.getWritableDatabase();
    
21.             }
    
22.         });
    
23.     }
    
24. }
    

复制代码

数据库创建就大功告成了，非常简单。