I am writing a board game app (like chess). The main view recognizes swipe gestures (UISwipeGestureRecognizer) started anywhere in its fullscreen view, which make the board rotating.
Now I added a square-shaped transparent subview exactly over the board. This is an UIControl subclass that detects touches - as moves of pawns around the board:
[self.view addSubview:self.boardControl]
I expected that swipe gestures will be blocked at the area of screen that is covered with UIControl subclass. And they are not. So when I make a quick touch and drag (a swipe) over my square boardControl, it first is detected as a pawn move, but then is detected again as swipe which rotates the board.
How can I make my UIControl subclass to block a flow of touch events started in its frame to its superviews?
I can prevent my app from reacting to swipe gestures, by filtering touches at the level of superview, either by:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
CGPoint location = [gestureRecognizer locationInView:self.view];
CGRect frame = self.boardControl.frame;
if ( CGRectContainsPoint(frame, location) )
return NO;
return YES;
}
or by:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch
{
CGPoint location = [touch locationInView:self.view];
CGRect frame = self.boardControl.frame;
if (CGRectContainsPoint(frame, location))
return NO;
return YES;
}
but I want to solve that issue one level earlier: I want boardControl to not pass up any of started within their frame touch events, higher in views hierarchy.
Can UIControl subclass "cover" its superview, and "eat" all touches it gets, so the superview will not need to access its frame to guess if such a touch has to be filtered out or not?
All you need is implement UIGestureRecognizerDelegate is provides way to make requested things.
I think you should start from gestureRecognizer:shouldReceiveTouch: examples
Here's how the scroll views work: One scroll view is paging enabled in the horizontal direction. Each 'page' of this scroll view contains a vertically scrolling UITableView. Without modification, this works OK, but not perfectly.
The behaviour that's not right: When the user scrolls up and down on the table view, but then wants to flick over to the next page quickly, the horizontal flick/swipe will not work initially - it will not work until the table view is stationary (even if the swipe is very clearly horizontal).
How it should work: If the swipe is clearly horizontal, I'd like the page to change even if the table view is still scrolling/bouncing, as this is what the user will expect too.
How can I change this behaviour - what's the easiest or best way?
NOTE For various reasons, a UIPageViewController as stated in some answers will not work. How can I do this with cross directional UIScrollViews (/one is a table view, but you get the idea)? I've been banging my head against a wall for hours - if you think you can do this then I'll more than happily award a bounty.
According to my understanding of the question, it is only while the tableView is scrolling we want to change the default behaviour. All the other behaviour will be the same.
SubClass UITableView. UITableViews are subClass of UIScrollViews. On the UITableView subClass implement one UIScrollView's UIGestureRecognizer's delegate method
- (BOOL)gestureRecognizer:(UIPanGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UISwipeGestureRecognizer *)otherGestureRecognizer
{
//Edit 1
//return self.isDecelerating;
//return self.isDecelerating | self.bounces; //If we want to simultaneous gesture on bounce and scrolling
//Edit 2
return self.isDecelerating || self.contentOffset.y < 0 || self.contentOffset.y > MAX(0, self.contentSize.height - self.bounds.size.height); // #Jordan edited - we don't need to always enable simultaneous gesture for bounce enabled tableViews
}
As we only want to change the default gesture behaviour while the tableView is decelerating.
Now change all 'UITableView's class to your newly created tableViewSubClass and run the project, swipe should work while tableView is scrolling. :]
But the swipe looks a little too sensitive while tableView is scrolling. Let's make the swipe a little restrictive.
SubClass UIScrollView. On the UIScrollView subclass implement another UIGestureRecognizer's delegate method gestureRecognizerShouldBegin:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
CGPoint velocity = [(UIPanGestureRecognizer *)gestureRecognizer velocityInView:self];
if (abs(velocity.y) * 2 < abs(velocity.x)) {
return YES;
}
}
return NO;
}
We want to make the "swipe is clearly horizontal". Above code only permits gesture begin if the gesture velocity on x axis is double than on y axis. [Feel free to increase the hard coded value "2" if your like. The higher the value the swipe needs to be more horizontal.]
Now change the `UiScrollView' class (which has multiple TableViews) to your ScrollViewSubClass. Run the project. :]
I've made a project on gitHub https://github.com/rishi420/SwipeWhileScroll
Although apple doesn't like this method too much:
Important: You should not embed UIWebView or UITableView objects in UIScrollView objects. If you do so, unexpected behavior can result
because touch events for the two objects can be mixed up and wrongly
handled.
I've found a great way to accomplish this.
This is a complete solution for the problem. In order to scroll the UIScrollView while your UITableView is scrolling you'll need to disable the interaction you have it.
- (void)viewDidLoad
{
[super viewDidLoad];
_myScrollView.contentSize = CGSizeMake(2000, 0);
data = [[NSMutableArray alloc]init];
for(int i=0;i<30;i++)
{
[data addObject:[NSString stringWithFormat:#"%d",i]];
}
UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
[self.view addGestureRecognizer:tap];
}
- (void)handleTap:(UITapGestureRecognizer *)recognizer
{
[_myTableView setContentOffset:_myTableView.contentOffset animated:NO];
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
scrollView.userInteractionEnabled = NO;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
scrollView.userInteractionEnabled = YES;
}
To sum up the code above, if the UITableView is scrolling, set userInteractionEnabled to NO so the UIScrollView will detect the swipe. If the UITableView is scrolling and the user taps on the screen, userInteractionEnabled will be set to YES.
Instead of using UIScrollView as a container for these multiple table views, try using a UIPageViewController.
You can even integrate this into your existing view controller setup as a child view controller (directly replacing the UIScrollView).
In addition, you'll likely want to implement the required methods from UIPageViewControllerDataSource and possibly one or more of the methods from UIPageViewControllerDelegate.
Did you try the methods : directionalLockEnabled of both your table and scroll and set them up to horizontal for one and vertical for the other ?
Edit :
1)
What you want to do is very complicate since the touch wait some time (like 0.1s) to know what your movement will be. And if your table is moving, it will take your touch immediately whatever it is (because it's suppose to be reactive movement on it).
I don't see any other solution for you but to override touch movement from scratch to detect immediately the kind of mouvement you want (like if the movement will be horizontal) but it will be more than hard to do it good.
2)
Another solution I can advise you is to make your table have left and right margin, where you can touch the parent scroll (pages thing so) and then even if your table is scrolling, if you touch here, only your paging scroll will be touched. It's simpler, but could not fit with your design maybe...
Use UIPageViewController and in the -viewDidLoad method (or any other method what best suits your needs or design) get UIPageViewController's UIScrollView subview and assign a delegate to it. Keep in mind that, its delegate property won't be nil. So optionally, you can assign it to another reference, and then assign your object, which conforms to UIScrollViewDelegate, to it. For example:
id<UIScrollViewDelegate> originalPageScrollViewDelegate = ((UIScrollView *)[pageViewController.view.subviews objectAtIndex:0]).delegate;
[((UIScrollView *)[pageViewController.view.subviews objectAtIndex:0]) setDelegate:self];
So that you can implement UIScrollViewDelegate methods with ease. And your UIPageViewController will call your delegate's -scrollViewDidScroll: method.
By the way, you may be obliged to keep original delegate, and respond to delegate methods with that object. You can see an example implementation in ViewPagerController class on my UI control project here
I faced the same thing recently. My UIScrollview was on paging mode and every page contained a UITableView and like you described it worked but not as you'd expected it to work. This is how solved it.
First I disabled the scrolling of the UIScrollview
Then I added a UISwipeGestureRecognizer to the actual UITableView for left and right swipes.
The action for those swipes were:
[scroll setContentOffset:CGPointMake(currentPointX + 320, PointY) animated:YES];
//Or
[scroll setContentOffset:CGPointMake(currentPointX - 320 , PointY) animated:YES];
This works flawlessly, the only down side is that if the user drags his finger on the UITableVIew that will be considered as a swipe. He won't be able to see half of screen A and half of screen B on the same screen.
You could subclass your scroll view and your table views, and add this gesture recognizer delegate method to each of them...
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:
(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
I can't be sure this is exactly what you are after, but it may come close.
I have a UIScrollView where I added a subview. The scrollview scrolls fine vertically and that is all it should do. I would now like to recognize left/right swipes in the subview with the help of a UISwipeGestureRecognizer. I know it is possible, but I have not come across a solution and several tries have been unsuccessful.
Try these:
Set the delegate of your UIGestureRecognizer and
Implement shouldRecognizeSimultaneouslyWithGestureRecognizer:
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
Implement shouldReceiveTouch:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
return YES;
}
Hope this helps
I was able to accomplish something related (adding a two-finger swipe gesture recognizer directly on the scroll view) with the new iOS 7 UIGestureRecognizerDelegate method:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldBeRequiredToFailByGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return otherGestureRecognizer == scrollView.panGestureRecognizer;
}
However, the results were not perfect - the delay waiting for the swipe gesture recognizer to fail first causes a lag in the scrollview's pan gesture recognizer getting its touches, so normal scrolling is noticeably delayed when you start to scroll.
I have a table with static cells. One of these cells has a view in it with a pan gesture recogniser on it.
When I am scrolling down my tableview, when I get to the cell with the view with pan gesture recogniser, scrolling doesn't seem to work. If I touch outside the view (to the side or top or bottom) it works and I can scroll. I have an if statement in my gesturerecognizer that tests whether a certain area has been touched, and if so performs an action.
I have looked at this issue (http://stackoverflow.com/questions/3295239/uigesturerecognizer-blocking-table-view-scrolling) but setting cancelsTouchesInView to NO didn't work, I don't have anywhere setting the state property and using the method - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
I don't know where to get the 'otherGestureRecognizer' from or what object to call that method on.
I'm assuming I wan't to put my gesture recogniser as the first argument, and the tableview's scroll gesture recogniser as the otherGestureRecogniser, is that correct? If so, how do I get that?
UIPanGestureRecognizer *windPanGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(moveWindHandle:)];
[self.windRangeView addGestureRecognizer:windPanGesture];
Then in my moveWindHandle:
-(void)moveWindHandle:(UIPanGestureRecognizer *)gesture
{
gesture.cancelsTouchesInView = NO;
isMovingHandle = [self isPoint:startedTouchAt insideHandle:_toHandleWindImageView];
if(isMovingHandle) {
if(gesture.state == UIGestureRecognizerStateBegan) {
//do stuff
}
}
else
{
//i want it to ignore this gesture and just scroll like normal if that is what hte user did
}
}
I have set the tableviewcontroller as a UIGestureRecognizerDelegate, but I don't know what to do with that.
You would not be the one calling -gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:. That method is called by the system. You need to set your table view controller as the delegate for your window pan gesture.
windPanGesture.delegate = self;
At that point, when you do the pan, the system will call the delegate method -gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: with your gesture recognizer as one argument and the scroll view's gesture recognizer as the other.
Update
You may also want to implement the -gestureRecognizerShouldBegin: method and return NO if you are not in one of the certain areas.
It's been a long day at the keyboard so I'm reaching out :-)
I have a UIPageViewController in a typical implementation that basically follows Apple's standard template. I am trying to add an overlay that will allow the user to do things like touch a button to jump to certain pages or dismiss the view controller to go to another part of the app.
My problem is that the UIPageViewController is trapping all events from my overlay subview and I am struggling to find a workable solution.
Here's some code to help the example...
In viewDidLoad
// Page creation, pageViewController creation etc....
self.pageViewController.delegate = self;
[self.pageViewController setViewControllers:pagesArray
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:NULL];
self.pageViewController.dataSource = self;
[self addChildViewController:self.pageViewController];
[self.view addSubview:self.pageViewController.view];
// self.overlay being the overlay view
if (!self.overlay)
{
self.overlay = [[MyOverlayClass alloc] init]; // Gets frame etc from class init
[self.view addSubview:self.overlay];
}
This all works great. The overlay gets created, it gets show over the top of the pages of the UIPageViewController as you would expect. When pages flip, they flip underneath the overlay - again just as you would expect.
However, the UIButtons within the self.overlay view never get the tap events. The UIPageViewController responds to all events.
I have tried overriding -(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch per the suggestions here without success.
UIPageViewController Gesture recognizers
I have tried manually trapping all events and handling them myself - doesn't work (and to be honest even if it did it would seem like a bit of a hack).
Does anyone have a suggestion on how to trap the events or maybe a better approach to using an overlay over the top of the UIPageViewController.
Any and all help very much appreciated!!
Try to iterate through UIPageViewController.GestureRecognizers and assign self as a delegate for those gesture and implement
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;
Your code may be like this:
In viewDidLoad
for (UIGestureRecognizer * gesRecog in self.pageViewController.gestureRecognizers)
{
gesRecog.delegate = self;
}
And add the following method:
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
if (touch.view != self.pageViewController.view]
{
return NO;
}
return YES;
}
The documented way to prevent the UIPageViewController from scrolling is to not assign the dataSource property. If you assign the data source it will move into 'gesture-based' navigation mode which is what you're trying to prevent.
Without a data source you manually provide view controllers when you want to with setViewControllers:direction:animated:completion method and it will move between view controllers on demand.
The above can be deduced from Apple's documentation of UIPageViewController (Overview, second paragraph):
To support gesture-based navigation, you must provide your view controllers using a data source object.