变量是写的，但从来没有读过？ [英] variable was written, but never read?

问题描述

我收到以下警告变量'isTaken'已写入，但从未读取：

func textFieldShouldEndEditing(textField: UITextField) -> Bool {

        var isTaken: Bool = false

        if textField == usernameTxt { var query = PFQuery(className: "_User")
        query = PFQuery(className: "_User")
        query.whereKey("username", equalTo: usernameTxt.text!)
        query.findObjectsInBackgroundWithBlock {
            (objects: [AnyObject]?, error: NSError?) in
            if error == nil {
                if (objects!.count > 0){

                    isTaken = true

                    }
                } else {
                    print("Username is available. ")
                }
            } else {
                print("error")
            }
          }
        }
        return true
    }

为什么我得到警告和如何

why am I getting the warning and how do I do away with it?

推荐答案

由于错误说变量isTaken被写入，但是从未读过意味着您正在创建 isTaken 实例，并为其分配一个值，但从未使用过。

As error says variable 'isTaken' was written to, but never read means you are creating isTaken instance and assigning a value to it but it never used.

这篇关于变量是写的，但从来没有读过？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！