On iOS 7, when UIAlertView is presented, its buttons seem to automatically have exclusiveTouch=YES set. This way, if you simultaneously press more than one button on alert view, nothing terribly will happen.
This is not the case on iOS 8. When I present UIAlertView with 2 buttons. And I press these 2 buttons at the same time, the app freezes.
I cannot access the UIButtons on that UIAlertView. I cannot access any of the subviews of UIAlertView for that matter.
alertView.subview returns empty array, no matter in which part of the lifecycle I call it.
I have managed to find a solution to the problem. I implement the UIAlertView's delegate method:
-(void)didPresentAlertView:(UIAlertView *)alertView
{
UIView *view = ((UIApplication*)[UIApplication sharedApplication]).keyWindow.rootViewController.presentedViewController.view;
[self setExclusiveTouchForView:view];
}
-(void) setExclusiveTouchForView:(UIView*)view
{
for (UIView *subview in view.subviews) {
subview.exclusiveTouch = YES;
[self setExclusiveTouchForView:subview];
}
}
At first it was confusing to see that neither of all the subviews inside the view variable is of class UIButton or UIControl.
It is not actually necessary to set exclusiveTouch property on all of the subviews. But I posted it like this to reduce code complexity.
It works fine. App no longer freezes when both of UIAlertView's buttons are pressed at the same time. Only one of the presses is accepted.
Related
In a UINavigation bar, there is a right custom share UIBarButtonItem and a back button in the left UIBarButtonItem. When simultaneously tapping on both buttons, the app produces a black view, possibly because both buttons are attempting to display a new view simultaneously - the share button presents a UIActivityViewController and the back button a VC from the prior screen.
In looking through similar questions here, I've tried the following solutions but neither prevented a black view from appearing on a simultaneous button touch:
Inserting exclusiveTouch into ViewDidLoad in the following 2 ways
a)
for(UIView *temp in self.navigationController.navigationBar.subviews)
{ [temp setExclusiveTouch:YES]; }
b) [self.navigationController.navigationBar setExclusiveTouch:YES];
Applying self.navigationController.navigationBar.userInteractionEnabled = NO; after a touch.
Are there other solutions?
Is this related to multi-threading?
In each touch event handler, add the following line:
[[UIApplication sharedApplication] beginIgnoringInteractionEvents];
When the handler has completed, execute the following:
[[UIApplication sharedApplication] endIgnoringInteractionEvents];
It's up to you to figure out what to consider the end of the handler. If you're pushing or popping view controllers, you might add that second line to the viewWillAppear of the relevant view controllers. If you're displaying a modal view controller, you can use the completion handler of -[UIViewController presentViewController:animated:completion:].
Pretty much simple you can use make use of ExclusiveTouch property in this case
[self.navigationController.navigationBar setExclusiveTouch:YES];
This is a Boolean value that indicates whether the receiver handles touch events exclusively.
Setting this property to YES causes the receiver to block the delivery of touch events to other views in the same window. The default value of this property is NO.
If you want only one button to respond to touches at a time, you need to set exclusiveTouch for that button, rather than for the parent view.
Put this just after you add your bar button items.
for(UIView *temp in self.navigationController.navigationBar.subviews)
{
[temp setExclusiveTouch:YES];
}
or you can set exclusiveTouch individually for each UIBarButton while creating them.
I am trying to create a user interface enabling users to switch between the keyboard and other menus when using a chat application.
On a click of the textField bar I want to raise either the keyboard or a collection view.
The problem occurs when I click the 'menu' button. I want the textField bar to raise revealing my menu view. Then, on a click on the keyboard button, instantly switch to the keyboard, rather than having it slide up from the bottom. This means I need to have the keyboard already loaded and hidden but in the background of the app.
Currently though the earliest I am managing to assign a variable to the keyboard is in the keyboardDidShow function.
-(void) keyboardDidShow: (NSNotification *) notification {
// Get the window the keyboard is a subview of
_window = [UIApplication sharedApplication].windows.lastObject;
_keyboard = _window.subviews[0];
}
This means that after it has been loaded once I can hide and reveal it, but I don't want it visible when it is loading this first time.
To achieve this using alternate means I have tried adding my extra views as subviews of the UIWindow the keyboard is created in:
[_window addSubview:_menuView];
[_window addSubview:_gamesView];
[_window addSubview:_stickerView];
[self hideSpecificView];
Unfortunately I keep coming across the same problem, until I have loaded the keyboard once it needs to fully load before I can get a pointer to it to hide it.
Here is a picture of my toolBar incase I am not being clear:
On clicking the menu icon or the stickers icon I want the bar to raise with a collection view. If I then click the textfield, with these views visible, I want to hide the visible view to immediately show the keyboard behind.
I have also tried experimenting with keyboardWillShow but as the window hasn't been loaded in front our screen I can't get a pointer to the keyboard to hide it before it loads.
An example of what I am after can be found many chat apps (facebook messenger, LINE, Kakao Talk)
Any help would be greatly appreciated
Although the way I came up with isn't perfect it works almost perfectly so hopefully this might help people in the future. If anyone else has solved it differently please post as it would be interesting to know how you did it.
I started by adding a class variable to a UIWindow in my header file and then setting off a timer to ping just after the keyboard will show method finishes. After this method has finished the keyboard has been created, just, and so I allocate it and hide it.
-(void) keyboardWillShow: (NSNotification *) notification {
// More keyboard code
_window = [UIApplication sharedApplication].windows.lastObject;
[NSTimer scheduledTimerWithTimeInterval:0.01
target:self
selector:#selector(allocateKeyboard)
userInfo:nil
repeats:NO];
}
- (void)allocateKeyboard {
if (!_keyboard) {
_keyboard = _window.subviews[0];
}
_keyboard.hidden = YES;
[self setViewForButtonType];
}
I have already previously added my other views, hidden them and constrained them to the bottom of the main view, this means that when the keyboard rises they do too.
- (void)viewDidLoad {
[self.view addSubview:_menuView];
[self.view addSubview:_gamesView];
[self.view addSubview:_stickerView];
}
...
- (void)hideViews {
_keyboard.hidden = YES;
_menuView.hidden = YES;
_gamesView.hidden = YES;
_stickerView.hidden = YES;
}
When buttons get pressed I simple then unhide the view that I want to see and hide the rest of the views.
When I say that this method doesn't work perfectly it is because if you load view main view and then click a button before the keyboard has loaded for the first time then you get a quick glimpse of the keyboard before the view appears over the top. This though only happens the first time and only if they don't click in the text field first.
Anyway, I found this was the best way of making views look like they are in front of the keyboard. Obviously my code was a lot longer and more complex (too long for here) but this is the gist of the method I used to solve it. Comment if you have any queries and I hope this helps.
Pressing the button quickly and not holding for a short time, will not highlight the button.
Different from a UIButton on a common UIView.
Like the head photo in official Twitter client got same issue.
Instagram client seems solved this, all buttons works fine.
Find same question here:
Why doesn't UIButton showsTouchWhenHighlighted work when the button is on a UITableViewCell?
But I still don't know how to fix it.
Well... a UITableView is a subclass of UIScrollView and the UIScrollView class is known to eat touches for it's own purpose.
When it realizes the touch was not meant for it, it passes it to it's immediate subview.
This feature is the delaysContentTouches property (which by default is YES).
Which is why, the UIButton shows it's highlighted state only after a extended touch because the touch event was with the UITableView for a short while until it determined whether the touch was meant for scrolling or swiping the cell and on realizing the touch was for neither, it immediately passes the touch event to the subView directly below it.
In case of a quick-tap, the button's highlighted state is bypassed due to this delay and the target selector method is called directly.
To show the highlighted state of the button in a UITableView (just as it would on a UIView) do:
For iOS7+:
In -viewDidLoad or anywhere appropriate do:
[yourTableViewObject setDelaysContentTouches:NO];
Also... The cell.subviews has a class UITableViewCellScrollView which apparently is another scrollView and we need to disable the delaysContentTouches property of this class as well.
So... in the -cellForRowAtIndexPath: method (just before return cell;) do:
NSArray *test = cell.subviews;
for (UIView *currentView in cell.subviews) {
if ([NSStringFromClass([currentView class]) isEqualToString:#"UITableViewCellScrollView"]) {
UIScrollView *svTemp = (UIScrollView *) currentView;
[svTemp setDelaysContentTouches:NO];
break;
}
}
For iOS 6-:
In iOS6, the cell.subviews has a UITableViewCellContentView class which is not a scrollView subclass and so all it takes is setting one parameter for the tableView alone.
So, in -viewDidLoad or anywhere appropriate, this is all that you need:
[yourTableViewObject setDelaysContentTouches:NO];
PS: By doing this, it will mess up with the scrolling of the tableView so use your better judgement.
I'm trying to achieve a similar keyboard interaction that Messages has in iOS 7. I have a UIView which contains a UITextView, and when the user selects it to start typing, I want to make this UIView the inputAccessoryView. This would take care of the animation for me, as well as the new UIScrollView keyboard dismiss interaction in iOS 7.
When the UITextView begins editing, I'm trying to set its inputAccessoryView to its parent UIView (which is already in the view hierarchy). The keyboard appears but not with an accessory view.
I've read some people are using a duo of UITextFields to make this work, but that seems like a bad way to achieve this.
Any suggestions?
A much easier solution is to make your input field the input accessory view of your view controller:
- (BOOL)canBecomeFirstResponder
{
return YES;
}
- (UIView *)inputAccessoryView
{
return self.yourInputField;
}
The view will be on screen at the bottom of the screen and when it becomes first responder in response to a user tapping it, the keyboard will be presented. The view will be animated such that it remains immediately above the keyboard.
The only way to get this to work is via a second text field. The idea is to make it a subview but not visible (due to crazy rect). You then switch firstResponder back and forth between it and the real text field while its getting delegate methods. I created a some one viewController test project and did this (you can copy paste and verify behavior with about 2 minutes of time):
#implementation ViewController
{
UITextField *field;
UITextField *dummyView;
}
- (void)viewDidLoad
{
[super viewDidLoad];
field = [[UITextField alloc] initWithFrame:CGRectMake(0, 460, 320, 20)];
field.borderStyle = UITextBorderStyleRoundedRect;
field.delegate = self;
//field.inputAccessoryView = field;
field.text = #"FOO";
[self.view addSubview:field];
dummyView = [[UITextField alloc] initWithFrame:CGRectMake(0, 40000, 320, 20)];
dummyView.delegate = self;
[self.view addSubview:dummyView];
}
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
if(textField == field && textField.superview == self.view) {
[field removeFromSuperview];
dummyView.inputAccessoryView = field;
[dummyView becomeFirstResponder];
}
return YES;
}
#end
I should add I've used this technique in shipping apps since iOS 4.
EDIT: So a couple of other ideas:
1) To make the glitch when the keyboard starts moving look a little better, you could take a snapshot of your textView, put that into a UIImageView, and when you remove the textView from the primary view, replace it with the UIImageView. Now the appearance is the same. Add an animation for the image so that noting happens for 50 ms, then the alpha goes to 0. Add a similar animation to your real textview, so that it has an alpha of 0 for 50 ms, then it goes to 1. You may be able to tweak this so the transition is good (but not great).
2) The way apple probably does this is to get the animation curve and timing from the keyboard moving notification. In this case they would add a accessory view with 0 height at first, and animate the textField so its tracking the keyboard, but above it. Both moving same distance at the same time. At the end of the animation, the textField is pulled out of self.view, the accessory view has its frame changed to have the height of the textField, and the textField is placed as a subview of the accessory container view. This should work but yeah, its a bit complex to do. If you want someone to code it for you offer a 100 pt bounty. You still need the dummy text field for when you go and move the textField at the end, since when you take it out of its containing view it will resign first responder. So at the end, you make the dummy field the first responder, move the textfield, then make the real textfield the first responder again.
This actually works best if you don't use .inputAccessoryView at all and instead just animate the position of the parent UIView as the keyboard opens and closes. Here is an answer describing the process step-by-step with all the code.
Just for starters: I'm already listening to keyboard will appear/disappear/change notifications. They're not firing. Neither are did appear/disappear/change.
When I have the keyboard up, and push a controller on top which also has the keyboard up (-[UITextView becomeFirstResponder] in viewWillAppear), no keyboard notifications are fired. This makes some sense, as the keyboard does not actually move in this animation, but it's certainly not desirable in this case.
How would I detect this scenario, and / or how can I get the current position of the keyboard when no notification has been fired? A global, shared listener is an option, but I'd prefer to avoid that if possible.
You would need to find the firstResponder, and if its a UITextField or UITextView then the keyboard is up or moving. No notification means its up already, so its old frame (relative to the window) is still valid. Unfortunately there is no easy way to find the firstReponder. I grabbed some code that recursively walked all the current view's subviews, looking for it.
EDIT:
- (UIView *)findFirstResponder
{
if (self.isFirstResponder) {
return self;
}
for (UIView *subView in self.subviews) {
UIView *firstResponder = [subView findFirstResponder];
if (firstResponder) return firstResponder;
}
return nil;
}