first-responder

问题 In the code below I am Initialising a NSViewController [a NSResponder], with a NSWindow , a NSOpenGLView , presenting the view and attempting to set the NSViewController as the windows first responder. It is not working. I was expecting to be able to hit a breakpoint in the keyUp: and keyDown: methods also below, but nothing is happening. Am I missing something? -(void)initwithFrame:(CGRect)frame { window = [[MyNSWindow alloc] initWithContentRect:frame styleMask:NSClosableWindowMask |

问题 Is there any way to do this? I tried putting the following into the subclass: - (BOOL)canBecomeFirstResponder { return YES; } But when I sent the object a becomeFirstResponder message, it still didn't become the first responder. 回答1: Yes, it is possible. You should: Override becomeFirstResponder to return YES . Set userInteractionEnabled to YES . Add a UITapGestureRecognizer to handle taps. Call becomeFirstResponder from the tap handler. You can even override inputView to get a input control

问题 I have a very basic UITableView with an attached UISearchBar, and here's the flow of what happens UITableView is empty, user taps UISearchBar, and brings up keyboard. Once the user taps the Search button - (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar { [searchBar resignFirstResponder]; //move the keyboard out of the way //Code.... } Works just fine, and moves the keyboard out of the way, and populates the UITableView. The problem is any subsequent search attempts. The same

问题 I have a webpage with a text field and a submit button. That webpage is loaded within a UIWebView. How would I programmatically press the submit button for that webpage? Alternatively, how would I programmatically make the text field within the webpage the first responder and display the soft keyboard? Just programmatically re-create the same behavior as if the user had touched the text field on the webpage. I would like to make the assumption that the source of the page is unknown. This is

问题 I have a menu item "foobar" that i need to enable on my main window (app delegate), but disable on all other windows. I'd like to know how to do that, because the first responder business is very confusing to me. Here's what i have now: "foobar" item is connected to first responder's "foobar:" custom action in MainMenu.xib there is a "foobar:" action in the main app delegate so the menu item is enabled and works now i load and "makeKeyAndOrderFront" another window i focus some control on that

问题 I am developing a Mac app using storyboards. I have a window that presents an NSViewController as its contents, which contains a "container view controller" that embeds an NSSplitViewController . The expected behaviour is for the NSSplitViewController to be part of the responder chain, such that a menu item that triggers the toggleSidebar action on the first responder actually collapses the item of the NSSplitViewController that's marked as a sidebar. However, this simply does not happen and

问题 I am confused about the iPhone responder chain. Specifically, in the iPhone event handling guide http://developer.apple.com/iPhone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/EventHandling/EventHandling.html, we have the following: The first responder is the responder object in an application (usually a UIView object) that is designated to be the first recipient of events other than touch events. But UIView is a subclass of UIResponder. And the UIResponder class reference

问题 I have a simple form (NSWindow) with 3 text fields. NSWindow's initialFirstResponder is 'pointing' to the first field ( NSTextField ). All three text fields are circularly linked to each other via nextKeyView . Problem that I have is that when I start the application from Xcode it'll focus on the text field that was last active (in focus) when the application closed. So for example, if I name text fields A, B and C and initialFirstResponder is set to A. Now if I start the application, focus

问题 I have a searchBar I'm setting in a tableviewcontroller. i've referenced this similar question UISearchBar cannot become first responder after UITableView did re-appear but am still unable to set it as first responder. In .h file: @property (strong, nonatomic) UISearchController *searchController; @property (strong, nonatomic) IBOutlet UISearchBar *searchBar; In view didload: self.searchController = [[UISearchController alloc]initWithSearchResultsController:nil]; self.searchController

问题 What are File Owner and First Responder in iOS - Xcode? 回答1: The File Owner is an instantiated, runtime object that owns the contents of your nib and its outlets/actions when the nib is loaded. It can be an instance of any class you like - take a look at the identity tab of the tool palette. File Owner is the main link between your application code and the contents of the nib file. For example, consider you have a UIViewController subclass with an IBOutlet for a UILabel. In interface builder