class has no initializers
来源：互联网 发布：优麒麟下安装windows 编辑：程序博客网 时间：2024/05/16 12:32
**
类的property必须要在designation initializer里实例化， 不然就用optional
var str:String?问号(?) 暗示包含的值是可选类型,也就是说可能包含 String 值也可能不包含值。
有时候在程序架构中,第一次被赋值之后,可以确定一个可选类型总会有值。在这种情况下,每次都要判断和解析可选值是非常低效的,因为可以确定它总会有值。
var str:String!感叹号( String! )来声明一个隐式解析可选类型
**
0 0
- class has no initializers
- class viewController has no initializers解决办法
- class viewcontroller has no initializers 如何fixed
- class viewController has no initializers解决办法
- Class has no initializers: Swift Error
- class viewController has no initializers解决办法
- swift class viewController has no initializers 的解决方法
- 'class QApplication' has no member named 'setMainWidget'
- class has no zero argument constructor
- error: ‘class QApplication’ has no member named ‘setMainWidget’
- 错误:'class QApplication' has no member named 'setMainwidget'
- Subresource for target class has no jax-rs annotations
- No message body writer has been found for class
- JSON: Property 'xxx' has no getter method in class 'class xxx'
- Qt: error: 'class QString' has no member named 'toAscii'(class QChar)
- no class
- gcc error: 'class A' has no member named 'b'：误用多态导致的错误
- this declaration has no storage class or type specifier。。。警告什么意思
- spring 多数据源的配置
- python中文乱码的解决方法
- [神经网络]1.6-Using neural nets to recognize handwritten digits-Implementing our network to classify（翻译）
- getParameterValues使用
- Android开发笔记（六十六）自定义对话框
- class has no initializers
- div的float:left与span标签
- Flags-Ural1225简单递推
- Scala中的String.split函数
- 在vmware fusion 8 for Mac上安装windows 7 64bit
- HashMap的工作原理
- 随笔
- RxJava 创建操作符form
- maven【2】（maven问题）
