SQLiteOpenHelper

阳光穿透心脏的1/2处 2022-07-18 01:49 87阅读 0赞

package com.example.sqlitedemo3;
    
    import android.app.Activity;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.Menu;
    import android.view.MenuItem;
    
    
    public class MainActivity extends Activity {
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            DBOpenHelper heDatabase=new DBOpenHelper(MainActivity.this,"stu.db");
            SQLiteDatabase db=heDatabase.getWritableDatabase();
            Cursor cursor=db.rawQuery("select * from stutb",null);
            if(cursor!=null){
            	while(cursor.moveToNext()){
            		Log.i("打印","姓名："+cursor.getString(1));
            	}
            	cursor.close();
            }
            db.close();
            
        }
    
    
    }

package com.example.sqlitedemo3;
    
    import android.content.Context;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteDatabase.CursorFactory;
    import android.database.sqlite.SQLiteOpenHelper;
    import android.util.Log;
    
    public class DBOpenHelper extends SQLiteOpenHelper{
    	
    public DBOpenHelper(Context context, String name) {
    		super(context, name,null,1);
    		// TODO Auto-generated constructor stub
    	}
    public DBOpenHelper(Context context, String name, CursorFactory factory,
    			int version) {
    		super(context, name, factory, version);
    		// TODO Auto-generated constructor stub
    	}
    	
    //首次创建数据库是调用，一般用于建库键表操作
    	@Override
    	public void onCreate(SQLiteDatabase db) {
    		// TODO Auto-generated method stub
    		Log.i("打印","姓名：");
    		db.execSQL("create table if not exists stutb(_id integer primary key autoincrement,name text not null,sex text not null,age integer not null)");
    		db.execSQL("insert into stutb(name,sex,age) values('张三','男',18)");
    		
    	}
    //当数据库版本发生变化时会自动执行
    	@Override
    	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    		// TODO Auto-generated method stub
    		
    	}
    
    }