xcode 在代码中设置“用户定义的运行时属性”
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Set "User Defined Runtime Attributes" in code
提问by Michael Bailey
This may be a silly question but I couldn't find an answer anywhere. If I want to create a UIButtonin code and need to set a runtime attribute how would I do so without the interface builder and strictly in code?
这可能是一个愚蠢的问题，但我在任何地方都找不到答案。如果我想UIButton在代码中创建一个并且需要设置运行时属性，我将如何在没有界面构建器的情况下并严格在代码中进行操作？
回答by Michael Bailey
Actually figured this out, like I said silly question.
其实想通了这一点，就像我说的愚蠢的问题。
[UIButton *loginbtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[loginbtn setValue:@"blah" forKey:@"myAttr"];
回答by Andrew Madsen
When you set a runtime attribute in Interface Builder, what you're actually doing is instructing the Nib loading machinery to call the corresponding setter method on that object during Nib loading. So, if you have a runtime attribute called for example "name" with a string value of "Bob", all that means is that at some point at runtime during Nib loading, the instance's -setName:method will be called with @"Bob"as the argument.
当您在 Interface Builder 中设置运行时属性时，您实际上是在指示 Nib 加载机制在 Nib 加载期间调用该对象上的相应 setter 方法。因此，如果您有一个名为“name”的运行时属性，其字符串值为“Bob”，这意味着在 Nib 加载期间的某个运行时点，实例的-setName:方法将@"Bob"作为参数被调用。
So, to do the same thing at runtime, you just set the property directly, perhaps in your view controller's -viewDidLoadmethod, or another appropriate place:
所以，要在运行时做同样的事情，你只需直接设置属性，也许在你的视图控制器的-viewDidLoad方法中，或者其他合适的地方：
self.button.name = @"Bob";
回答by iOS dev
Wanted to provide an updated answer which leverages Swift property wrappers to cleanly attribute UI elements which should be ignored.
想要提供一个更新的答案，它利用 Swift 属性包装器来干净地属性应该被忽略的 UI 元素。
Swift 5.1+ Property Wrapper
Swift 5.1+ 属性包装器
@propertyWrapper
public struct HeapIgnore<T> {
public var wrappedValue: T {
didSet {
(wrappedValue as? NSObject)?.setValue(true, forKey: "heapIgnore")
}
}
public init(wrappedValue: T) {
self.wrappedValue = wrappedValue
}
}
Example Usage
示例用法
... // Inside ViewController
@HeapIgnore
@IBOutlet private var passwordTextField: UITextField!
I've implemented this solution and confirmed in both the Live View and Events Visualizer that Heap ignores events generated by UI elements attributed with the property wrapper.
我已经实现了这个解决方案，并在 Live View 和 Events Visualizer 中确认 Heap 会忽略由属性包装器属性的 UI 元素生成的事件。
回答by Fr4ncis
You need to reference somehow the UIButton in the code (usually by creating an IBOutlet) and then you can access its properties as you would do when you create a button programmatically.
您需要以某种方式在代码中引用 UIButton（通常通过创建一个 IBOutlet），然后您可以像以编程方式创建按钮一样访问其属性。
If you want to create the button programmatically for instance:
例如，如果要以编程方式创建按钮：
UIButton *button = [[UIButton alloc] initWithFrame:frame];
[button setTitle:@"Title" forState:UIControlStateNormal];
