selector

问题 [ NOTE This question was originally formulated under Swift 2.2. It has been revised for Swift 4, involving two important language changes: the first method parameter external is no longer automatically suppressed, and a selector must be explicitly exposed to Objective-C.] Let\'s say I have these two methods in my class: @objc func test() {} @objc func test(_ sender:AnyObject?) {} Now I want to use Swift 2.2\'s new #selector syntax to make a selector corresponding to the first of these methods

问题 I need to detect when the user taps the \"back\" button on the navigation bar, in order to perform some operations when that occurs. I\'m trying to set manually an action to such button, this way: [self.navigationItem.backBarButtonItem setAction:@selector(performBackNavigation:)]; - (void)performBackNavigation:(id)sender { // Do operations [self.navigationController popViewControllerAnimated:NO]; } I firstly placed that code in the view controller itself, but I found that self.navigationItem

问题 This is a button selector such that when normal it appears red, when pressed it appears grey. I would like to ask how could the code be further directly modified such that when PRESSED the text size and color could also change? Many thanks! <item android:state_pressed=\"true\" > <shape xmlns:android=\"http://schemas.android.com/apk/res/android\"> <stroke android:width=\"2dp\" android:color=\"@color/black\" /> <solid android:color=\"@color/grey\"/> <padding android:left=\"5dp\" android:top=\

问题 I\'m trying to create an NSTimer in Swift but I\'m having some trouble. NSTimer(timeInterval: 1, target: self, selector: test(), userInfo: nil, repeats: true) test() is a function in the same class. I get an error in the editor: Could not find an overload for \'init\' that accepts the supplied arguments When I change selector: test() to selector: nil the error disappears. I\'ve tried: selector: test() selector: test selector: Selector(test()) But nothing works and I can\'t find a solution in