I have a UIScrollView ontop of my UIViewController recreating an effect like in the Gowalla iPhone app when you're on a spot's page. Under my scroll view I have a button that I want to be able to perform it's action even when the scroll view's frame covers it up (where it's ontop of the button, the scroll view's clear). How would I do something like this? Is it possible? (it has to be, Gowalla [somehow] did it)
As for me, I will transfer touch event to another view by override following methods.
– touchesBegan:withEvent:
– touchesMoved:withEvent:
– touchesEnded:withEvent:
– touchesCancelled:withEvent:
Like this way,
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
// pass touch event by default implement.
[super touchesBegan:touches withEvent:event];
// redirect the touch events.
[anotherView touchesBegain:touches withEvent:event];
}
hitTest:withEvent: is used to decide which view should response touch event on the view hierarchy tree. If the view doesn't want to response touch event, it will return nil in hitTest. As result the above touch event methods won't be called.
I have no idea what this "Gowalla" app might do; hopefully, your description of "a button behind the scroll view, that you can touch 'through' the scroll view" is accurate.
If your button behind the scroll view can be sized to fill the entire contentSize area of the scroll view without screwing up your interface, the easiest solution would be to just put it inside the scroll view (under all the other views) and do just that.
Otherwise, your best bet is probably to create a custom view with a clear background to be placed in the scroll view as above. The easy solution is to have the custom view (probably a UIControl) just do whatever touching the button does. If that's not possible for some reason, your best option would be to override hitTest:withEvent: on the custom view to return the underlying button. I'd be wary of overriding hitTest:withEvent: on the scroll view itself, as that might interfere with scrolling.
Try adding the button on top of the scroll view. The only problem with that is if you hit the button, you will not be able to interact with the scrollView, but it will still be visible.
Related
Possibly a duplicate, but I couldn't find an exact answer to my problem searching SO tonight...
I have a UIButton which contains a UIScrollView, so the button is the superview.
All I want to do is pass a single-tap event from the UIScrollView subview to the UIButton superview, and have the UIButton handle it as it would if the user tapped the button directly.
Setting the scroll view's userInteractionEnabled property to NO won't work for me because there is content the user can scroll. Doing so would defeat the purpose of the scroll view.
Is this possible? Thanks!
Like huoxinbird said, it's definitely not common to lay your views like that.
In the case where you are solidly adamant about this, you could use UITapGestureRecognizer and have it call the button's target and selector.
If you wanted to include the button highlight and such, then you may have to subclass UITapGestureRecognizer and forward the touchesEnded to the button.
Create a subclass of scrollview and override
-(BOOL)touchesShouldBegin:(NSSet *)touches withEvent:(UIEvent *)event inContentView:(UIView *)view
{
return YES;
}
Also subclass the uibutton(Your superview) and handle touches in touches began.
Usually you don't put scrollview within a button. Instead consider using a UIView as the superview of scrollview. Or tell us more about your use case, so I can understand why you have to design in this way.
My problem is about tap detection.
I have a uiviewcontroller and there are some controls on uiview (labels, buttons, tableview, imageview, etc..)
When I tap the uibutton I display a small uiview (200x150), if the user taps the uibuttons in smallview I hide the smallview.
But I can't hide the uiview if the user taps the background.
I tried this code..
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
//NSLog(#"Touches began.");
[self hideShareView];
}
It doesn't work if I tap the another button in the uiviewcontrols view.
I just want my uiviewcontrol's uiview to react first.
I think its about firstResponder but I dont know how to set it first.
edit: i want it to work like a uiPopover in ipad.
I believe that the correct approach is to add a new transparent UIView when you display your "smallview". You should add a UITapGestureRecognizer to that UIView, in order to trigger the desired selector when the tap is detected. Also, you must ensure that the views are arranged properly, with your smallview being the one at the top, the transparent UIView being immediately below and the rest of the view hierarchy below the transparent UIView.
Finally, you should ensure to remove the transparent UIView from your view hierarchy at the same time that you remove your smallview.
Does that make sense?
Please have a look at this question (how-to-make-a-superview-intercept-button-touch-events), it does seem highly related.
try your hands with bringing your small view (i.e. shareview) to front or sent your main view behind your small view.
If it still doesn't work & you don't want your main view to perform any action when smallview is opened then try
[<YOUR_MAIN_VIEW> setUserInteractionEnabled:NO];
, but MAKE SURE you can do this only when you don't want your main view to perform any action when smallview is opened
I'm using the touchesEnded: method to do some work when I lift a finger off my UIScrollView, but my problem (and i've confirmed using NSLog) is that the touchesEnded: method seems to only get called when I tap on my scroll view and not when I touch and hold/slide my finger and then let go?
Is there another method I need to use? (btw i'm calling super as well)
I need a way to do stuff as soon as the user removes their fingers off the view
When you simply tap, the scroll view will pass touches through to its subviews. But if you start dragging, the scrollview will send a touchesCancelled message to the subview and process the touches itself. Check out the methods on UIScrollViewDelegate - there's probably something there you can use.
Alternatively, UIScrollView has a property canCancelContentTouches. If you turn that off, its subviews will always receive touches, but of course then the scroll view won't scroll.
I have a UIViewController and an associated with it UIView. The UIView has a number of subviews.
How to handle touch event inside a specified rectangle in my UIViewController subclass?
This handling should be transparent: UIView and its subviews should still receive their touch events even if they intersect with the specified rectangle.
P.S.
Overriding touchesBegan in the view
controller doesn't work. Inner views
doesn't pass events through.
Adding a custom
button to the end of UIView subviews
list also doesn't work. Inner
subviews doesn't receive touch
events.
touchesBegan/touchesMoved/touchesEnded is probably the way to go. Depending on exactly what you are trying to do, UIGestureRecognizer may also be an option.
To make sure subviews pass events up, set userInteractionEnabled to YES on the subviews.
UIView sets this to YES by default, but some subclasses (notably UILabel) override this and set it to NO.
Just because the views don't pass events through by default doesn't necessarily mean that's the way it has to be.
You could subclass the views that you are using and have them pass the events onto the view controller.
Another idea is to literally have a transparent handler on top of all of your views. That is, have a transparent UIView that sits above your views, handling touch events but also passing them through. I have no idea if this works in practice, but it sounds like it would.
Your views, and their controllers can handle a touch using touchesBegan, touchesEnded or touchesMoved. Within touchesBegan as an example you can then choose to pass the event to
the next responder in the responder chain. This way each of your views will get a chance to do something based on the touch event.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//do something here and then pass the event on
[self.nextResponder touchesBegan:touches withEvent:event];
}
I used the "View-based Application" template in Xcode for an iPhone project and went into the view controller's XIB.
I changed the view from a basic UIView to a UIScrollView, and now the method
(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
never gets called. I have an NSLog statement in there. It gets called just fine when the controller's view is a UIView, so what's different/special about UIScrollViews that you don't receive touch events? How can I respond to a touch event?
UIScrollView does not pass on all touch events. It does this because it tries to interpret swipe and scroll gestures itself.
Have a look at this thread: http://discussions.apple.com/thread.jspa?messageID=7519817 to learn about UIScrollView and events. The bottom line is that you can handle events in your view's -(void)touchesEnded:(NSSet *)aTouches withEvent:(UIEvent *)anEvent but it's not straight forward.
I have personally seen some funkyness in UIScollView's effect on hit testing sub views.
I don't have any direct experience here, but I was looking over documentation that might explain this yesterday. I think you'll find that UIScrollView captures touches in order to handle its scrolling. Take a look at delaysContentTouches in the documentation window.
Just use a custom content subview, then implement touchesEnded:withEvent: in that view. You'll get all the taps you want!