}overridefunc didReceiveMemoryWarning() {//Swift 中一定注意不要主动清理视图或者控件//因为懒加载不会再次创建} }
If multiple threads access a lazy property at the same time before the value has been computed, it’s possible the computation could be performed more than once, along with any side effects the computation may have. lazy修饰的变量是在第一次访问的时候初始化的,如果多线程访问这个Lazy变量,将会...
A lazy var is a property whose initial value is not calculated until the first time it’s called. It’s part of a family of properties in which we have constant properties,computed properties, and mutable properties. A lazy property might be lesser known to beginners in Swift but are actua...
When apropertyis only needed at some point in time, you can prefix it with the lazy keyword so it’ll be “excluded” from the initialization process and it’s default value will be assigned on-demand. This can be useful for types that are expensive to create, or needs more time to b...
在Swift 中我们使用在变量属性前加lazy关键字的方式来简单地指定延时加载。比如上面的的代码我们在 Swift 中重写的话,会是这样: classClassA{lazyvarstr:String={letstr="Hello"print("只在首次访问输出")returnstr }() } 我们在使用lazy作为属性修饰符时,只能声明属性是变量。另外我们需要显式地指定属性类型,并...
无法编译 var notLazy: String = { return self.string }() // 3. 可以编译 lazy var lazy: String = { return self.string }() } 而非lazy 的存储属性是不能在初始化完成之前访问 self 的,编译器会提示你: property initializers run before 'self' is available 或者self unresolved 之类的消息。
GO FURTHER, FASTER: Try the Swift Career Accelerator today! >> Lazy propertiesQuestion 1/6: Which of these are true?Hint: Click to show.Option 1: Lazy properties act like property observers. Option 2: Lazy properties can be used inside any kind of structs. ...
1: @property (nonatomic, strong) NSMutableArray *players; 2:3: - (NSMutableArray *)players {4: if (!_players) {5: _players = [[NSMutableArray alloc] init];6: }7: return _players;8: } 实际上我们可以这样写: 1: lazy var players: NSMutableArray = {2: var temporaryPlayers = NS...
iOS Development with Swift and Xcode See tutors like this A lazy property is a special property whose value is not assigned until it is used. This is useful for avoiding excessive computation while an instance is being initialized or for deferring the creation of a value until more informatio...
Creating a lazy property in Kotlin is pretty simple, we define it using by lazy and provide a function initializer. At a later point, when the property is first accessed it will be initialized using the function we provided and then on future accesses the cached value will be returned instea...