I have a UIScrollView with paging enabled, my goal is to detect if the user reaches third page by swiping, I want to redirect the user to another view. I have tried many ways. tried it in scrollViewWillBeginDragging , tried inbuilt pan gesture in scrollview methods using handleSwipeGesture . But unfortunately nothing worked. Can any body please tell me how to face this issue. Thanks in advance.
I recommend you to use this code
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
int page=scrollview.contentoffset.x/scrollview.frame.size.width
if(page == 3)
{
// redirect to your view.
}
}
This will give you the page no. you are currently on. and the condition will redirect to a specified view.
Related
In iOS 11 the system apps all compress the navigation bar as you scroll down if you enable prefersLargeTitles:
I can't figure out how to implement this in my own apps though, the bar stays the same by default:
The only thing I can see is Hide Bars On Swipe, but that hides the whole bar rather than compressing it:
This is just an empty project created in Xcode 9 beta and with a new storyboard added.
What do I need to do to get the same behaviour as the system apps?
Don't set anything regarding Large Titles in Interface Builder / Storyboard, only in code. That worked for me.
So in the navigation bar in storyboards, Prefers Large Titles unchecked.
In your view controller:
self.navigationController?.navigationBar.prefersLargeTitles = true
It seems like this issue is happening to people for different reasons. None of the above answers helped me, but here's what DID work...
I deconstructed my app to find the cause, which was the view hierarchy in the storyboard. It appears that the UITableView view HAS to the the first view in your view controller. I had a UITableView with two UIImageViews behind it and that's what was causing the issue. Once I removed those UIImageViews everything worked correctly.
My fix: I ended up creating a UIView in code, adding my two image views to that, THEN adding that UIView to the UITableview.backgroundView.
Hope this helps someone.
If you have to target older iOS versions, you’ll also have to wrap the assignment in an availability check:
if #available(iOS 11, *) {
self.navigationController?.navigationBar.prefersLargeTitles = true
}
if #available(iOS 11.0, *) {
navigationController?.navigationBar.prefersLargeTitles = true
navigationController?.navigationBar.topItem?.title = "Hello"
navigationController?.navigationItem.largeTitleDisplayMode = .automatic
let attributes = [
NSAttributedStringKey.foregroundColor : UIColor.red,
]
navigationController?.navigationBar.largeTitleTextAttributes = attributes
} else {
// Fallback on earlier versions
}
http://iosrevisited.blogspot.in/2017/09/navigation-bar-with-large-titles-and.html
I have been trying to focus the first button but focus engine takes the third button right below the tab bar as the first item to be focussed. I tried with preferred focus view but found that when i place the buttons in vertical order then preferred takes the preferred view to be focussed but when i placed all the buttons in horizontal plane it always takes the third button.The other approach i can think of if Focus Guide but i wonder how that will work in this scenario?
override weak var preferredFocusedView: UIView? {
get {
return thrirdButton
}
}
It happens because focus engine takes the nearest possible focus element as 1st element as you can see from the picture attached.I have attached the context screenshot for the view controller. Any help or clue to solve this will be appreciated.
Solution :
We need to add focus guide just above button 3 and redirect it to button one when the focus guide is focussed.
private var focusGuide = UIFocusGuide()
self.view.addLayoutGuide(focusGuide)
self.focusGuide.bottomAnchor.constraintEqualToAnchor(self.button3.topAnchor).active = true
self.focusGuide.leftAnchor.constraintEqualToAnchor(self.button3.leftAnchor).active = true
// Width and height
self.focusGuide.widthAnchor.constraintEqualToAnchor(self.button3.widthAnchor).active = true
self.focusGuide.heightAnchor.constraintEqualToAnchor(self.button3.heightAnchor).active = true
focusGuide.centerXAnchor.constraintEqualToAnchor(self.button3.centerXAnchor).active = true
override func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator) {
self.focusGuide.preferredFocusedView = button1
}
Try adding a UIFocusGuide just above the button rows. In that case, before reaching the button, it will hit your focus guide in which you can redirect the preferredFocusedView to that particular button. The code to redirect is to be done by overriding didUpdateFocusInContext method.
Assuming you have setup the focus guide in viewDidload, the following is a sample,
override func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator) {
super.didUpdateFocusInContext(context, withAnimationCoordinator: coordinator)
self.focusGuide.preferredFocusedView = self.mypreferredbutton
}
TO initialise a focus guide ( Do the addition of guide to view in viewDidLoad)
var focusGuide = UIFocusGuide()
self.view.addLayoutGuide(self.sidefocusGuide)
self.focusGuide.leftAnchor.constraintEqualToAnchor(self.placerLabel.leftAnchor).active = true
self.focusGuide.rightAnchor.constraintEqualToAnchor(self.placerLabel.rightAnchor).active = true
self.focusGuide.topAnchor.constraintEqualToAnchor(self.audioTable.topAnchor).active = true
I too faced a similar issue but somehow able to do it through this. The preferredFocusedView approach will also work, but you have to do lot of circus by updating some reference variable and then calling setneedsfocusupdate for that view. Try the focus guide way. Hope it helps.
EDITED:
I have added code how to setup the guide. In this case I have put the guide on the right side of my view. So, whenever your focus hits the guide, it redirects to the preferredfocusguide view that you want the focus to go to in the didUpdateFocusInContext. "There is only one view in focus at anytime.", remember thes ? So, the moment it hits the guide, the overriden method gets hit which in turn moves your focus to the guide's preferred view. For examples, you can refer to Apple's UIKitCatlog app for tvOS and here is one link explaining the same.
The best way to give the initial focus to your preferred view is by using preferredFocusEnivronments.
override var preferredFocusEnvironments: [UIFocusEnvironment] {
return [firstButton]
}
preferredFocusEnvironments will be called before didUpdateFocus, that way you can inform the system, where you want the focus to be redirected.
The project have some views with different buttons. When I hide a view and show the other view, I can't get the focus on my button.
I think is related to setNeedsFocusUpdate. I have read the Apple doc. There is not any example.
Does anyone know how to do it and put an example (Objective C)?
You need to override preferredFocusedView, and when you are hiding one view and showing there call this method setNeedsFocusUpdate, your preferredFocusedView implementation should be something like this
- (UIView *)preferredFocusedView
{
// Add your logic here, it could be more complicated then what is below
if (view1.hidden)
{
return _button;
}
else
{
return _button2
}
}
And if you want to make custom view get focus, override canBecomeFocused method and return true
Edit
You can use add a breakpoint and execute this command po [buttonYouWantToFocus _whyIsThisViewNotFocusable] it will tell you why its not focusable.
If you are adding a sub view programmatically, maybe this is what you want:
- (UIView *)preferredFocusedView {
return [view1 preferredFocusedView];
}
I realize your question is specific to Objective-C but here is a way to solve for this in Swift. You need to override the preferredFocusedView property.
override var preferredFocusedView: UIView? {
guard primaryView.hidden == false else {
return secondaryView
}
return primaryView
}
Then just call setNeedsFocusUpdate() whenever an event happens that causes your views to be hidden. Hope this helps...
Another option (if you don't want to use preferredFocusedView) is, instead of setting your view to be hidden, simply remove it from it's superview, like so:
myView.removeFromSuperview()
This automatically takes the focus away from the button that is removed and gives it to another one that is still on screen.
In my app, I have a couple of UISlider instances to change various values. The values are displayed right next to the slider, as well as rendered in a 3d space in another visible part of the app.
The 3d part includes some rather heavy calculations, and right now it doesn't seem possible to update it live as the slider changes. That would imply that I'd have to set the slider's continuous property to NO, therefore only getting updates when the slider has finished changing.
I'd prefer to have the displayed value update live, however. Is there a way to have a slider that is continuous (so I can update my value-label in real time) and still sends some kind of message once the user has finished interacting with it? My gut feeling right now is to subclass UISlider and override the touchesEnded: method. Is that feasible?
You can do this with simple target/actions.
Set a target and action for the UIControlEventValueChanged event, and then another target and action for the UIControlEventTouchUpInside event. With the continuous property set to YES, the value changed event will fire as the slider changes value, while the touch up inside event will only fire when the user releases the control.
I just had to do this, so I looked up touch properties, and used the full IBAction header.
This should be a viable alternative for people who want some extra control, though Jas's is definitely easier on the code side.
- (IBAction)itemSlider:(UISlider *)itemSlider withEvent:(UIEvent*)e;
{
UITouch * touch = [e.allTouches anyObject];
if( touch.phase != UITouchPhaseMoved && touch.phase != UITouchPhaseBegan)
{
//The user hasn't ended using the slider yet.
}
}
:D
Also note you should connect the UIControlEventTouchUpOutside event as well in case the user drags his finger out of the control before lifting it.
In Swift 3:
#IBAction func sliderValueChanged(_ slider: UISlider, _ event: UIEvent) {
guard let touch = event.allTouches?.first, touch.phase != .ended else {
// ended
return
}
// not ended yet
}
I am currently using pagination in a UIScrollView, and for tracking any page change I use;
-(void) scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
if (_previousContentOffset > _pageContainer.contentOffset.x)
{
NSLog(#"Less");
_currentPageIdx--;
}
else if (_previousContentOffset < _pageContainer.contentOffset.x)
{
_currentPageIdx++;
NSLog(#"More");
}
}
Now the problem is that, this method isn't tracking the touch fast enough, so when this method is called, the user can be 3 pages along if he/she is paging like a maniac. I tried setting
_pageContainer.decelerationRate = UIScrollViewDecelerationRateFast;
but that didn't make the tracking much faster.
Is there a solution or alternative for this?
Use scrollViewDidScroll: instead. It is being called continuously while the user scrolls.