安卓app开发经常会需要嵌入式数据库sqlite的辅助,它可以存放我们必要的应用数据,下面介绍下如何使用java连接读取sqlite中的数据。
本文中的代码经本人测试可用,可以参考。
代码如下:
DBHelper.java
package com.web.redrain;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
public DBHelper(Context context) {
super(context, "user.db", null, 1); //创建user.db数据库
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE table IF NOT EXISTS user"
+ " (_id INTEGER PRIMARY KEY AUTOINCREMENT, id TEXT, name TEXT, img TEXT, isOnline TEXT)");//创建user表
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("ALTER TABLE user ADD COLUMN other TEXT");
}
}调用方法:
DBHelper helper = new DBHelper(getBaseContext());
SQLiteDatabase db = helper.getWritableDatabase();
db.execSQL("delete from user where 1=1");
db.execSQL("insert into user (id,name,img,isOnline) values('我是个人','见人在此','我会乱说','我是神,oh,my god!!!!')");
Cursor c = db.rawQuery("select * from user", null);
while (c.moveToNext()) {
alert(c.getString(c.getColumnIndex("id")));
alert(c.getString(c.getColumnIndex("name")));
alert(c.getString(c.getColumnIndex("img")));
alert(c.getString(c.getColumnIndex("isOnline")));
}
alert方法:
public void alert(String txt){
Toast.makeText(MainActivity.this,txt, 1).show();
}本文由PHP中文网提供
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