数据库方法的使用

package com.example.qiji0330;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
* Created by 小柒先生。 on 2018/4/1.
*/

public class Dao {

private final Myhelper myhelper;

public Dao(Context context) {
myhelper = new Myhelper(context);
}

public void insert(String path,String json){
SQLiteDatabase writableDatabase = myhelper.getWritableDatabase();
ContentValues contentValues=new ContentValues();
contentValues.put("urlpath",path);
contentValues.put("jsondata",json);

long person = writableDatabase.insert("person", null, contentValues);
}

public String query(String path){
String data = "";
SQLiteDatabase writableDatabase = myhelper.getWritableDatabase();
Cursor cursor = writableDatabase.query("person", null, "urlpath = ?", new String[]{path}, null, null, null);
if(cursor!=null){
while (cursor.moveToNext()){
data = cursor.getString(cursor.getColumnIndex("jsondata"));
}
}

return data;
}

}