错误检查无法正确解析查询

Question

所以我有一个名为“类”的解析服务器中的类，我试图在我的程序内部实现一个错误检查查询。但是，当我尝试错误地检查我的查询以搜索类时，程序总是说搜索是成功的，即使该类类型的对象不在查询中，Xcode项目也会正确构建。下面是代码：

@IBAction func searchClass(_ sender: Any) { 

    let query = PFQuery(className: "Classes") 
    query.findObjectsInBackground { (success, error) in 
     if error != nil{ 
      self.createAlert(title: "Error", message: "Cannot find class") 
     } else { 
      self.createAlert(
       title: "Success", message: "Found the query") 
      self.classSuccess = true 
      self.flipCardButton.alpha = 0 
      UIView.transition(from: self.classQuery, to: self.classRate, duration: 0.5, options: .transitionFlipFromRight) 
      self.goBackButton.alpha = 1 
     } 
    } 

这里是我的应用程序内的搜索按钮：

Screenshot of Simulator

什么可能出问题，使分析查询检查始终打印成功？

Answer 1

我想你错过了你的查询中的成功声明。

let query = PFQuery(className: "Classes") 
query.findObjectsInBackground { (success, error) in 
    if error != nil{ 
     print(error ?? "") 
     self.createAlert(title: "Error", message: "Cannot find class") 
    } 

    if success { 
     self.createAlert(
      title: "Success", message: "Found the query") 
     self.classSuccess = true 
     self.flipCardButton.alpha = 0 
     UIView.transition(from: self.classQuery, to: self.classRate, duration: 0.5, options: .transitionFlipFromRight) 
     self.goBackButton.alpha = 1 

    } else { 
     self.createAlert(title: "Error", message: "Cannot find class") 
    } 
}