I am trying to follow this tutorial (https://www.youtube.com/watch?v=UZ0mp3-JuzY&index=25&list=PLE83F832121568D36) on drag & drop in Cocoa app.
I am using XCode6, so some methods used in the video are deprecated.
I have make subclass of NSView, named DropView, and I have make my customView identifier to be DropView
Here is the code that I have now:
#import "DropView.h"
#implementation DropView
-(id)initWithFrame:(NSRect)frameRect
{
self = [super initWithFrame:frameRect];
if(self) {
[self registerForDraggedTypes:[NSArray arrayWithObject:NSURLPboardType]];
}
return self;
}
-(NSDragOperation) draggingEntered:(id<NSDraggingInfo>)sender
{
if ([NSImage canInitWithPasteboard:[sender draggingPasteboard]] && [sender draggingSourceOperationMask] & NSDragOperationCopy)
{
NSLog(#"ENTERED");
return NSDragOperationCopy;
}
NSLog(#"NEVER ENTERED IN DRAGGING ENTERED METHOD");
return NSDragOperationNone;
}
-(NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)sender
{
NSLog(#"DRAGGING");
return NSDragOperationCopy;
}
-(void)draggingEnded:(id<NSDraggingInfo>)sender
{
NSLog(#"ENDED!");
}
-(void)draggingExited:(id<NSDraggingInfo>)sender
{
NSLog(#"EXITED!");
}
-(BOOL)prepareForDragOperation:(id<NSDraggingInfo>)sender
{
NSLog(#"DID I EVER ENTER PREPARE FOR DRAG OPERATION METHOD?");
return YES;
}
-(BOOL)performDragOperation:(id<NSDraggingInfo>)sender
{
if([NSImage canInitWithPasteboard:[sender draggingPasteboard]])
{
NSImage *newImage = [[NSImage alloc ]initWithPasteboard:[sender draggingPasteboard]];
[self setImage:newImage];
}
return YES;
}
-(void)concludeDragOperation:(id<NSDraggingInfo>)sender
{
[self setNeedsDisplay:YES];
}
#end
I am not getting any error, but It seems that no code is executed. My guess is that frameRect is nil, that is is not initialized, but i have no idea why. Anyone can help me with this problem?
Regards, John
Ok, the solution was that DropView to be subclass of NSBox, instead of NSView, even that I don't understand why...
Is -initWithFrame: called?
If you created your view from IB, register for drag and drop in -initWithCoder: or -awakeFromNib
This seems to be one of the most frequently discussed topics here but I couldn't find a solution which actually works. I'm posting this question to share a solution which I found as well as hoping to find a better/cleaner solution
Description of situation:
There is a UIWebview in my application
There is text input/area in the webview
Long pressing on the text area/input brings up a context menu with 'cut', 'copy', 'define' etc.
We need to disable this menu without disabling user input.
What I've tried so far
(Stuff that doesn't work) :
Override canPerformAction
This solution tells us to add canPerformAction:withSender: to either subclass of UIWebview or in a delegate of UIWebview.
- (BOOL) canPerformAction:(SEL)action withSender:(id)sender
{
if (action == #selector(defineSelection:))
{
return NO;
}
else if (action == #selector(translateSelection:))
{
return NO;
}
else if (action == #selector(copy:))
{
return NO;
}
return [super canPerformAction:action withSender:sender];
}
Does not work because the canPerformAction: in this class is does not get called for menu items displayed.
Since the sharedMenuController interacts with the first responder in the Responder chain, implementing canPerformAction in the container skipped select and selectAll because they had already been handled by a child menu.
Manipulating CSS
Add the following to CSS:
html {
-webkit-user-select: none;
-webkit-touch-callout: none;
-webkit-tap-highlight-color:rgba(0,0,0,0);
}
This does work on images and hyperlinks but not on inputs.
:(
The root cause of the first solution not working is the subview called UIWebBrowserView. This seems to be the view whose canPerformAction returns true for any action displayed in the context menu.
Since this UIWebBrowserView is a private class we shouldn't try to subclass it (because it will get your app rejected).
So what we do instead is we make another method called mightPerformAction:withSender:, like so-
- (BOOL)mightPerformAction:(SEL)action withSender:(id)sender {
NSLog(#"******Action!! %#******",NSStringFromSelector(action));
if (action == #selector(copy:))
{
NSLog(#"Copy Selector");
return NO;
}
else if (action == #selector(cut:))
{
NSLog(#"cut Selector");
return NO;
}
else if (action == NSSelectorFromString(#"_define:"))
{
NSLog(#"define Selector");
return NO;
}
else if (action == #selector(paste:))
{
NSLog(#"paste Selector");
return NO;
}
else
{
return [super canPerformAction:action withSender:sender];
}
}
and add another method to replace canPerformAction:withSender: with mightPerformAction:withSender:
- (void) replaceUIWebBrowserView: (UIView *)view
{
//Iterate through subviews recursively looking for UIWebBrowserView
for (UIView *sub in view.subviews) {
[self replaceUIWebBrowserView:sub];
if ([NSStringFromClass([sub class]) isEqualToString:#"UIWebBrowserView"]) {
Class class = sub.class;
SEL originalSelector = #selector(canPerformAction:withSender:);
SEL swizzledSelector = #selector(mightPerformAction:withSender:);
Method originalMethod = class_getInstanceMethod(class, originalSelector);
Method swizzledMethod = class_getInstanceMethod(self.class, swizzledSelector);
//add the method mightPerformAction:withSender: to UIWebBrowserView
BOOL didAddMethod =
class_addMethod(class,
originalSelector,
method_getImplementation(swizzledMethod),
method_getTypeEncoding(swizzledMethod));
//replace canPerformAction:withSender: with mightPerformAction:withSender:
if (didAddMethod) {
class_replaceMethod(class,
swizzledSelector,
method_getImplementation(originalMethod),
method_getTypeEncoding(originalMethod));
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}
}
}
}
And finally call it in the viewDidLoad of the ViewController:
[self replaceUIWebBrowserView:self.webView];
Note: Add #import <objc/runtime.h> to your viewController then error(Method) will not shown.
Note: I am using NSSelectorFromString method to avoid detection of private API selectors during the review process.
Also you can hide menu:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(menuWillBeShown:) name:UIMenuControllerWillShowMenuNotification object:nil];
...
- (void)menuWillBeShown:(NSNotification *)notification {
dispatch_async(dispatch_get_main_queue(),^{
[[UIMenuController sharedMenuController] setMenuVisible:NO animated:NO];
});
}
The essential trick here is dispatch_async.
I am trying to disable the back gesture for my view controller using the following set of code.
In FirstViewController.m, I'm setting the delegate of interactivePopGestureRecognizer
- (void) viewWillLoad {
// Other stuff..
self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
And then implementing the <UIGestureRecognizerDelegate> method and returning NO.
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
return NO;
}
And in dealloc I'm setting the delegate to nil. (I have read somewhere that in iOS 7, you have to manually set the delegates to nil)
- (void)dealloc {
self.navigationController.delegate = nil;
self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}
This works in the FirstViewController. But when I push SecondViewController to this, the gesture does not work on that either. How can I disable the gesture in FirstViewController only?
Also when I pop FirstViewController to go to RootViewController and then try to push FirstViewController again, I get the object deallocated error :
[FirstViewController gestureRecognizer:shouldReceiveTouch:]: message sent to deallocated instance 0x14ed0280
Why else do I need to do other than setting the delegates to nil? Or am I setting it in the wrong place?
Try the below untested code in your FirstViewController :
-(void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
}
-(void) viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
self.navigationController.interactivePopGestureRecognizer.enabled = YES;
}
I originally put these answers into a comment below the accepted answer, but I feel this needs to be said as an answer to get more visibility.
More often than not, you will find that the accepted answer does not work. This is because viewWillAppear: can be called before the view is added to a navigation controller's view hierarchy, and so self.navigationController is going to be nil. Because of this, the interactivePopGestureRecognizer may not be disabled in some cases. You're better off calling it in viewDidAppear: instead.
Here's code that will work (assuming your view controller is correctly added to a navigation controller's view hierarchy):
Objective-C
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[[[self navigationController] interactivePopGestureRecognizer] setEnabled:NO];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[[self navigationController] interactivePopGestureRecognizer] setEnabled:YES];
}
Swift
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
navigationController?.interactivePopGestureRecognizer?.isEnabled = false
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
navigationController?.interactivePopGestureRecognizer?.isEnabled = true
}
I tried the all above but they did not work for me.So i tried this and it works for me on both IOS7 and IOS8.
Just make sure that your view controller implements this protocol i.e UIGestureRecognizerDelegate
and write the code given below.
-(void)viewWillAppear : (BOOL) animated {
[super viewWillAppear : animated];
if ([self.navigationController respondsToSelector:#selector(interactivePopGestureRecognizer)]) {
self.navigationController.interactivePopGestureRecognizer.enabled =
NO;
self.navigationController.interactivePopGestureRecognizer.delegate =
self;
}
}
-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
if ([gestureRecognizer isEqual:self.navigationController.interactivePopGestureRecognizer]) {
return NO;
} else {
return YES;
}
}
I found out setting the gesture to disabled only doesn't always work. It does work, but for me it only did after I once used the backgesture. Second time it wouldn't trigger the backgesture. Furthermore, as John Rogers said, it's import to use the viewDidAppear and viewWillAppear as the navigationController else would be nil.
Fix for me was to delegate the gesture and implement the shouldbegin method to return NO:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
// Disable iOS 7 back gesture
if ([self.navigationController respondsToSelector:#selector(interactivePopGestureRecognizer)]) {
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// Enable iOS 7 back gesture
if ([self.navigationController respondsToSelector:#selector(interactivePopGestureRecognizer)]) {
self.navigationController.interactivePopGestureRecognizer.enabled = YES;
self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
return NO;
}
This just worked for me in xCode 7:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
self.navigationController!.interactivePopGestureRecognizer!.enabled = false
}
override func viewWillDisappear(animated: Bool) {
super.viewDidDisappear(animated)
self.navigationController!.interactivePopGestureRecognizer!.enabled = true
}
For only one view, I don't know the way... But I use the next code to disable fully the swipe gesture:
in your AppDelegate.m
if ([[UIDevice currentDevice].systemVersion floatValue] >= 7){
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
}
How do I disable the "Use small size" option in the toolbar? I am using Xcode 4.
(That's the option that appears when users go to customize the Toolbar.)
If you're not distributing on the Mac App Store, and don't mind subclassing private methods, you can create an NSToolbarSubclass and override _allowsSizeMode: to return NO:
- (BOOL)_allowsSizeMode:(NSToolbarSizeMode)mode {
return mode != NSToolbarSizeModeSmall;
}
This has the added benefit of removing the checkbox from the customization sheet, as well.
You could subclass NSToolbar, override -setSizeMode: and in your implementation call [super setSizeMode: NSToolbarSizeModeRegular];.
If you're instantiating the toolbar in Interface Builder then make sure you assign your subclass to the toolbar in the nib.
#implementation RKToolbar
- (void)setSizeMode:(NSToolbarSizeMode)aSizeMode
{
[super setSizeMode:NSToolbarSizeModeRegular];
}
#end
This won't remove the checkbox from the customize panel but it will prevent it from doing anything.
There's not really a supported way to remove the checkbox. This does work but it's pretty hacky:
//in your NSToolbar subclass
- (void)runCustomizationPalette:(id)sender
{
[super runCustomizationPalette:sender];
NSWindow* toolbarWindow = [NSApp mainWindow];
NSWindow* sheet = [toolbarWindow attachedSheet];
for(NSView* view in [[sheet contentView] subviews])
{
if([view isKindOfClass:[NSButton class]])
{
if([[[(NSButton*)view cell] valueForKey:#"buttonType"] integerValue] == NSSwitchButton)
{
[view setHidden:YES];
}
}
}
}
Thanks to Rob Keniger for the excellent start. If you can have your custom toolbar as a delegate of your window, you can avoid having "Use small size" visible by getting at the sheet before it is displayed on screen. Do this by implementing [NSToolbar window:willPositionSheet:usingRect:] in the custom toolbar class. Elsewhere in your code, you'll need to do:
[myWindowWithToolbar setDelegate:myInstanceOfXXToolbar];
Here's the updated custom toolbar class:
#implementation XXToolbar
- (void)setSizeMode:(NSToolbarSizeMode)aSizeMode
{
[super setSizeMode:NSToolbarSizeModeRegular];
}
- (NSRect)window:(NSWindow *)window willPositionSheet:(NSWindow *)sheet usingRect:(NSRect)rect {
NSView *buttonView = nil;
for(NSView* view in [[sheet contentView] subviews])
{
if([view isKindOfClass:[NSButton class]])
{
if([[[(NSButton*)view cell] valueForKey:#"buttonType"] integerValue] == NSSwitchButton)
{
buttonView = view;
break;
}
}
}
if (buttonView) {
[buttonView setHidden:YES];
// This is important as it causes the sheet to redraw without the button off screen
[[sheet contentView] display];
}
return rect;
}
#end
Hope you find this useful.
Here's a Swift 2.2 version of #MacGreg's solution. You can keep your NSWindowDelegate wherever you like, just ensure at least the following is called:
var toolbar: UniformToolbar!
func window(window: NSWindow, willPositionSheet sheet: NSWindow, usingRect rect: NSRect) -> NSRect {
toolbar.removeSizeToggle(window: sheet)
return rect
}
Toolbar Subclass without the Checkbox
class UniformToolbar: NSToolbar {
override var sizeMode: NSToolbarSizeMode {
get {
return NSToolbarSizeMode.Regular
}
set { /* no op */ }
}
func removeSizeToggle(window window: NSWindow) {
guard let views = window.contentView?.subviews else { return }
let toggle: NSButton? = views.lazy
.flatMap({ (view: NSView) -> NSButton? in view as? NSButton })
.filter({ (button: NSButton) -> Bool in
guard let buttonTypeValue = button.cell?.valueForKey("buttonType")?.unsignedIntegerValue,
buttonType = NSButtonType(rawValue: buttonTypeValue)
else { return false }
return buttonType == .SwitchButton
})
.first
toggle?.hidden = true
window.contentView?.display()
}
}
I submitted my app a little over a week ago and got the dreaded rejection email today. It tells me that my app cannot be accepted because I'm using a non-public API; specifically, it says,
The non-public API that is included in your application is firstResponder.
Now, the offending API call is actually a solution I found here on SO:
UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
UIView *firstResponder = [keyWindow performSelector:#selector(firstResponder)];
How do I get the current first responder on the screen? I'm looking for a way that won't get my app rejected.
If your ultimate aim is just to resign the first responder, this should work: [self.view endEditing:YES]
In one of my applications I often want the first responder to resign if the user taps on the background. For this purpose I wrote a category on UIView, which I call on the UIWindow.
The following is based on that and should return the first responder.
#implementation UIView (FindFirstResponder)
- (id)findFirstResponder
{
if (self.isFirstResponder) {
return self;
}
for (UIView *subView in self.subviews) {
id responder = [subView findFirstResponder];
if (responder) return responder;
}
return nil;
}
#end
iOS 7+
- (id)findFirstResponder
{
if (self.isFirstResponder) {
return self;
}
for (UIView *subView in self.view.subviews) {
if ([subView isFirstResponder]) {
return subView;
}
}
return nil;
}
Swift:
extension UIView {
var firstResponder: UIView? {
guard !isFirstResponder else { return self }
for subview in subviews {
if let firstResponder = subview.firstResponder {
return firstResponder
}
}
return nil
}
}
Usage example in Swift:
if let firstResponder = view.window?.firstResponder {
// do something with `firstResponder`
}
A common way of manipulating the first responder is to use nil targeted actions. This is a way of sending an arbitrary message to the responder chain (starting with the first responder), and continuing down the chain until someone responds to the message (has implemented a method matching the selector).
For the case of dismissing the keyboard, this is the most effective way that will work no matter which window or view is first responder:
[[UIApplication sharedApplication] sendAction:#selector(resignFirstResponder) to:nil from:nil forEvent:nil];
This should be more effective than even [self.view.window endEditing:YES].
(Thanks to BigZaphod for reminding me of the concept)
Here's a category that allows you to quickly find the first responder by calling [UIResponder currentFirstResponder]. Just add the following two files to your project:
UIResponder+FirstResponder.h:
#import <Cocoa/Cocoa.h>
#interface UIResponder (FirstResponder)
+(id)currentFirstResponder;
#end
UIResponder+FirstResponder.m:
#import "UIResponder+FirstResponder.h"
static __weak id currentFirstResponder;
#implementation UIResponder (FirstResponder)
+(id)currentFirstResponder {
currentFirstResponder = nil;
[[UIApplication sharedApplication] sendAction:#selector(findFirstResponder:) to:nil from:nil forEvent:nil];
return currentFirstResponder;
}
-(void)findFirstResponder:(id)sender {
currentFirstResponder = self;
}
#end
The trick here is that sending an action to nil sends it to the first responder.
(I originally published this answer here: https://stackoverflow.com/a/14135456/322427)
Here is a Extension implemented in Swift based on Jakob Egger's most excellent answer:
import UIKit
extension UIResponder {
// Swift 1.2 finally supports static vars!. If you use 1.1 see:
// http://stackoverflow.com/a/24924535/385979
private weak static var _currentFirstResponder: UIResponder? = nil
public class func currentFirstResponder() -> UIResponder? {
UIResponder._currentFirstResponder = nil
UIApplication.sharedApplication().sendAction("findFirstResponder:", to: nil, from: nil, forEvent: nil)
return UIResponder._currentFirstResponder
}
internal func findFirstResponder(sender: AnyObject) {
UIResponder._currentFirstResponder = self
}
}
Swift 4
import UIKit
extension UIResponder {
private weak static var _currentFirstResponder: UIResponder? = nil
public static var current: UIResponder? {
UIResponder._currentFirstResponder = nil
UIApplication.shared.sendAction(#selector(findFirstResponder(sender:)), to: nil, from: nil, for: nil)
return UIResponder._currentFirstResponder
}
#objc internal func findFirstResponder(sender: AnyObject) {
UIResponder._currentFirstResponder = self
}
}
It's not pretty, but the way I resign the firstResponder when I don't know what that the responder is:
Create an UITextField, either in IB or programmatically. Make it Hidden. Link it up to your code if you made it in IB.
Then, when you want to dismiss the keyboard, you switch the responder to the invisible text field, and immediately resign it:
[self.invisibleField becomeFirstResponder];
[self.invisibleField resignFirstResponder];
For a Swift 3 & 4 version of nevyn's answer:
UIApplication.shared.sendAction(#selector(UIView.resignFirstResponder), to: nil, from: nil, for: nil)
Here's a solution which reports the correct first responder (many other solutions won't report a UIViewController as the first responder, for example), doesn't require looping over the view hierarchy, and doesn't use private APIs.
It leverages Apple's method sendAction:to:from:forEvent:, which already knows how to access the first responder.
We just need to tweak it in 2 ways:
Extend UIResponder so it can execute our own code on the first responder.
Subclass UIEvent in order to return the first responder.
Here is the code:
#interface ABCFirstResponderEvent : UIEvent
#property (nonatomic, strong) UIResponder *firstResponder;
#end
#implementation ABCFirstResponderEvent
#end
#implementation UIResponder (ABCFirstResponder)
- (void)abc_findFirstResponder:(id)sender event:(ABCFirstResponderEvent *)event {
event.firstResponder = self;
}
#end
#implementation ViewController
+ (UIResponder *)firstResponder {
ABCFirstResponderEvent *event = [ABCFirstResponderEvent new];
[[UIApplication sharedApplication] sendAction:#selector(abc_findFirstResponder:event:) to:nil from:nil forEvent:event];
return event.firstResponder;
}
#end
Using Swift and with a specific UIView object this might help:
func findFirstResponder(inView view: UIView) -> UIView? {
for subView in view.subviews as! [UIView] {
if subView.isFirstResponder() {
return subView
}
if let recursiveSubView = self.findFirstResponder(inView: subView) {
return recursiveSubView
}
}
return nil
}
Just place it in your UIViewController and use it like this:
let firstResponder = self.findFirstResponder(inView: self.view)
Take note that the result is an Optional value so it will be nil in case no firstResponder was found in the given views subview hierarchy.
The first responder can be any instance of the class UIResponder, so there are other classes that might be the first responder despite the UIViews. For example UIViewController might also be the first responder.
In this gist you will find a recursive way to get the first responder by looping through the hierarchy of controllers starting from the rootViewController of the application's windows.
You can retrieve then the first responder by doing
- (void)foo
{
// Get the first responder
id firstResponder = [UIResponder firstResponder];
// Do whatever you want
[firstResponder resignFirstResponder];
}
However, if the first responder is not a subclass of UIView or UIViewController, this approach will fail.
To fix this problem we can do a different approach by creating a category on UIResponder and perform some magic swizzeling to be able to build an array of all living instances of this class. Then, to get the first responder we can simple iterate and ask each object if -isFirstResponder.
This approach can be found implemented in this other gist.
Hope it helps.
Iterate over the views that could be the first responder and use - (BOOL)isFirstResponder to determine if they currently are.
Rather than iterate through the collection of views looking for the one that has isFirstResponder set, I too send a message to nil, but I store the receiver of the message so I can return it and do whatever I wish with it.
Additionally, I zero out the optional that holds the found responder in a defer statement from within the call itself. This ensures no references remain--even weak ones--at the end of the call.
import UIKit
private var _foundFirstResponder: UIResponder? = nil
extension UIResponder {
static var first:UIResponder? {
// Sending an action to 'nil' implicitly sends it to the first responder
// where we simply capture it and place it in the _foundFirstResponder variable.
// As such, the variable will contain the current first responder (if any) immediately after this line executes
UIApplication.shared.sendAction(#selector(UIResponder.storeFirstResponder(_:)), to: nil, from: nil, for: nil)
// The following 'defer' statement runs *after* this getter returns,
// thus releasing any strong reference held by the variable immediately thereafter
defer {
_foundFirstResponder = nil
}
// Return the found first-responder (if any) back to the caller
return _foundFirstResponder
}
// Make sure to mark this with '#objc' since it has to be reachable as a selector for `sendAction`
#objc func storeFirstResponder(_ sender: AnyObject) {
// Capture the recipient of this message (self), which is the first responder
_foundFirstResponder = self
}
}
With the above, I can resign the first responder by simply doing this...
UIResponder.first?.resignFirstResponder()
But since my API actually hands back whatever the first responder is, I can do whatever I want with it.
Here's an example that checks if the current first responder is a UITextField with a helpMessage property set, and if so, shows it in a help bubble right next to the control. We call this from a 'Quick Help' button on our screen.
func showQuickHelp(){
if let textField = UIResponder?.first as? UITextField,
let helpMessage = textField.helpMessage {
textField.showHelpBubble(with:helpMessage)
}
}
The support for the above is defined in an extension on UITextField like so...
extension UITextField {
var helpMessage:String? { ... }
func showHelpBubble(with message:String) { ... }
}
Now to support this feature, all we have to do is decide which text fields have help messages and the UI takes care of the rest for us.
Peter Steinberger just tweeted about the private notification UIWindowFirstResponderDidChangeNotification, which you can observe if you want to watch the firstResponder change.
If you just need to kill the keyboard when the user taps on a background area why not add a gesture recognizer and use it to send the [[self view] endEditing:YES] message?
you can add the Tap gesture recogniser in the xib or storyboard file and connect it to an action,
looks something like this then finished
- (IBAction)displayGestureForTapRecognizer:(UITapGestureRecognizer *)recognizer{
[[self view] endEditing:YES];
}
Just it case here is Swift version of awesome Jakob Egger's approach:
import UIKit
private weak var currentFirstResponder: UIResponder?
extension UIResponder {
static func firstResponder() -> UIResponder? {
currentFirstResponder = nil
UIApplication.sharedApplication().sendAction(#selector(self.findFirstResponder(_:)), to: nil, from: nil, forEvent: nil)
return currentFirstResponder
}
func findFirstResponder(sender: AnyObject) {
currentFirstResponder = self
}
}
This is what I did to find what UITextField is the firstResponder when the user clicks Save/Cancel in a ModalViewController:
NSArray *subviews = [self.tableView subviews];
for (id cell in subviews )
{
if ([cell isKindOfClass:[UITableViewCell class]])
{
UITableViewCell *aCell = cell;
NSArray *cellContentViews = [[aCell contentView] subviews];
for (id textField in cellContentViews)
{
if ([textField isKindOfClass:[UITextField class]])
{
UITextField *theTextField = textField;
if ([theTextField isFirstResponder]) {
[theTextField resignFirstResponder];
}
}
}
}
}
This is what I have in my UIViewController Category. Useful for many things, including getting first responder. Blocks are great!
- (UIView*) enumerateAllSubviewsOf: (UIView*) aView UsingBlock: (BOOL (^)( UIView* aView )) aBlock {
for ( UIView* aSubView in aView.subviews ) {
if( aBlock( aSubView )) {
return aSubView;
} else if( ! [ aSubView isKindOfClass: [ UIControl class ]] ){
UIView* result = [ self enumerateAllSubviewsOf: aSubView UsingBlock: aBlock ];
if( result != nil ) {
return result;
}
}
}
return nil;
}
- (UIView*) enumerateAllSubviewsUsingBlock: (BOOL (^)( UIView* aView )) aBlock {
return [ self enumerateAllSubviewsOf: self.view UsingBlock: aBlock ];
}
- (UIView*) findFirstResponder {
return [ self enumerateAllSubviewsUsingBlock:^BOOL(UIView *aView) {
if( [ aView isFirstResponder ] ) {
return YES;
}
return NO;
}];
}
With a category on UIResponder, it is possible to legally ask the UIApplication object to tell you who the first responder is.
See this:
Is there any way of asking an iOS view which of its children has first responder status?
You can choose the following UIView extension to get it (credit by Daniel):
extension UIView {
var firstResponder: UIView? {
guard !isFirstResponder else { return self }
return subviews.first(where: {$0.firstResponder != nil })
}
}
You can try also like this:
- (void) touchesBegan: (NSSet *) touches withEvent: (UIEvent *) event {
for (id textField in self.view.subviews) {
if ([textField isKindOfClass:[UITextField class]] && [textField isFirstResponder]) {
[textField resignFirstResponder];
}
}
}
I didn't try it but it seems a good solution
This is good candidate for recursion! No need to add a category to UIView.
Usage (from your view controller):
UIView *firstResponder = [self findFirstResponder:[self view]];
Code:
// This is a recursive function
- (UIView *)findFirstResponder:(UIView *)view {
if ([view isFirstResponder]) return view; // Base case
for (UIView *subView in [view subviews]) {
if ([self findFirstResponder:subView]) return subView; // Recursion
}
return nil;
}
you can call privite api like this ,apple ignore:
UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
SEL sel = NSSelectorFromString(#"firstResponder");
UIView *firstResponder = [keyWindow performSelector:sel];
Swift version of #thomas-müller's response
extension UIView {
func firstResponder() -> UIView? {
if self.isFirstResponder() {
return self
}
for subview in self.subviews {
if let firstResponder = subview.firstResponder() {
return firstResponder
}
}
return nil
}
}
I would like to shared with you my implementation for find first responder in anywhere of UIView. I hope it helps and sorry for my english. Thanks
+ (UIView *) findFirstResponder:(UIView *) _view {
UIView *retorno;
for (id subView in _view.subviews) {
if ([subView isFirstResponder])
return subView;
if ([subView isKindOfClass:[UIView class]]) {
UIView *v = subView;
if ([v.subviews count] > 0) {
retorno = [self findFirstResponder:v];
if ([retorno isFirstResponder]) {
return retorno;
}
}
}
}
return retorno;
}
The solution from romeo https://stackoverflow.com/a/2799675/661022 is cool, but I noticed that the code needs one more loop. I was working with tableViewController.
I edited the script and then I checked. Everything worked perfect.
I recommed to try this:
- (void)findFirstResponder
{
NSArray *subviews = [self.tableView subviews];
for (id subv in subviews )
{
for (id cell in [subv subviews] ) {
if ([cell isKindOfClass:[UITableViewCell class]])
{
UITableViewCell *aCell = cell;
NSArray *cellContentViews = [[aCell contentView] subviews];
for (id textField in cellContentViews)
{
if ([textField isKindOfClass:[UITextField class]])
{
UITextField *theTextField = textField;
if ([theTextField isFirstResponder]) {
NSLog(#"current textField: %#", theTextField);
NSLog(#"current textFields's superview: %#", [theTextField superview]);
}
}
}
}
}
}
}
Update: I was wrong. You can indeed use UIApplication.shared.sendAction(_:to:from:for:) to call the first responder demonstrated in this link: http://stackoverflow.com/a/14135456/746890.
Most of the answers here can't really find the current first responder if it is not in the view hierarchy. For example, AppDelegate or UIViewController subclasses.
There is a way to guarantee you to find it even if the first responder object is not a UIView.
First lets implement a reversed version of it, using the next property of UIResponder:
extension UIResponder {
var nextFirstResponder: UIResponder? {
return isFirstResponder ? self : next?.nextFirstResponder
}
}
With this computed property, we can find the current first responder from bottom to top even if it's not UIView. For example, from a view to the UIViewController who's managing it, if the view controller is the first responder.
However, we still need a top-down resolution, a single var to get the current first responder.
First with the view hierarchy:
extension UIView {
var previousFirstResponder: UIResponder? {
return nextFirstResponder ?? subviews.compactMap { $0.previousFirstResponder }.first
}
}
This will search for the first responder backwards, and if it couldn't find it, it would tell its subviews to do the same thing (because its subview's next is not necessarily itself). With this we can find it from any view, including UIWindow.
And finally, we can build this:
extension UIResponder {
static var first: UIResponder? {
return UIApplication.shared.windows.compactMap({ $0.previousFirstResponder }).first
}
}
So when you want to retrieve the first responder, you can call:
let firstResponder = UIResponder.first
Code below work.
- (id)ht_findFirstResponder
{
//ignore hit test fail view
if (self.userInteractionEnabled == NO || self.alpha <= 0.01 || self.hidden == YES) {
return nil;
}
if ([self isKindOfClass:[UIControl class]] && [(UIControl *)self isEnabled] == NO) {
return nil;
}
//ignore bound out screen
if (CGRectIntersectsRect(self.frame, [UIApplication sharedApplication].keyWindow.bounds) == NO) {
return nil;
}
if ([self isFirstResponder]) {
return self;
}
for (UIView *subView in self.subviews) {
id result = [subView ht_findFirstResponder];
if (result) {
return result;
}
}
return nil;
}
Simplest way to find first responder:
func sendAction(_ action: Selector, to target: Any?, from sender: Any?, for event: UIEvent?) -> Bool
The default implementation dispatches the action method to the given
target object or, if no target is specified, to the first responder.
Next step:
extension UIResponder
{
private weak static var first: UIResponder? = nil
#objc
private func firstResponderWhereYouAre(sender: AnyObject)
{
UIResponder.first = self
}
static var actualFirst: UIResponder?
{
UIApplication.shared.sendAction(#selector(findFirstResponder(sender:)), to: nil, from: nil, for: nil)
return UIResponder.first
}
}
Usage:
Just get UIResponder.actualFirst for your own purposes.