Question

我正在尝试运行此查询，但它无法正常工作，我似乎无法找到它的错误。

public boolean verifyUser(String name , String pword){
   boolean result = false;
   SQLiteDatabase db = this.getReadableDatabase();
   try {   
   Cursor res =  db.rawQuery( "select * from user where username="+name+" and password="+pword+"", null );

      int count = res.getCount(); 

      res.moveToFirst();
      if (count == 0) 
      {
          result = false;
      }
      else{
        result = true;
      }
   }
      catch (SQLiteException se ) {
          Log.e(getClass().getSimpleName(), "Could not log in");
      }
      return result;
      //return true;
   }

Answer 1

在SQL中，您需要将字符串文字放在'single quotes'中。更好的是，使用参数：

Cursor res =  db.rawQuery( "select * from user where username=? and password=?",
    new String[] { name, pword } );

Answer 2

复制并粘贴以下查询

select * from user where username='"+name+"' and password='"+pword+"'"

实际上你错过了单引号

Answer 3

选中此项，编辑了您的代码。

public boolean verifyUser(String name , String pword){
   boolean result = false;
   SQLiteDatabase db = this.getReadableDatabase();
   try {   
   Cursor res =  db.rawQuery( "select * from user where username='"+name+"' and password='"+pword+"'", null );

      int count = res.getCount(); 

      //res.moveToFirst(); //Remove this line (It may be crashing because of this line.)
      if (count == 0) 
      {
          result = false;
      }
      else{
       res.moveToFirst();
        result = true;
      }
   }
      catch (SQLiteException se ) {
          Log.e(getClass().getSimpleName(), "Could not log in");
      }
      return result;
      //return true;
   }

运行原始sqlite查询

3 个答案: