I have implemented my own custom subclass of UIView and overridden the drawRect: method.
In my custom view I also want the handle touches, so I also overridden touchesBegan, touchesMoved and touchesEnded.
This works fine but if the number of views on the screen increases then I have to use a UIScrollView as the root view of my UIViewController.
Once my custom UIView becomes the subview of UIScrollView, then it does not receive the touch events. Even though I move my finger within my custom UIView, the scroll view gets scrolled (all my touch events go to the UIScrollView).
How do I solve this problem?
There are several approaches you could try:
Try setting the below properties on the UIScrollView:
scrollView.delaysContentTouches = NO;
scrollView.canCancelContentTouches = NO;
See similar SO questions/answers here, here.
Implement hitTest:withEvent:. See here, here.
Use a UIGestureRecognizer. See here, here.
I would personally recommend using a UIGestureRecognizer, but it depends on your specific situation (any of these options may work fine for you).
Have a look at this response from another question: https://stackoverflow.com/a/4629821/193254
You'll have to subclass the scrollview too, and implement that hitTest: method.
Related
I have a UICollectionView with custom cells- They have a UITextView that mostly covers the entire cell. This presents a problem when using didSelectItemAtIndexPath. The only way to trigger it is by tapping outside the UITextView. I want it to trigger wherever in the cell you tap, whether there is a text view or not. How can this be done?
didSelectItemAtIndexPath is called when none of the subView of collectionViewCell respond to that touch. As the textView respond to those touches, so it won't forward those touches to its superView, so collectionView won't get it.
override hitTest:withEvent method of your collectionViewCell or CollectionView subclass and always return self from them.so it explicitly makes collectionView as first responder.
I would suggest to use UIGestureRecognizer for each cell and when it taped to send it to UITextView or whatever , perhaps there maybe a better solutions , but I would use this 1 because of simplicity reasons.
Do you override touchesEnded: withEvent: ?
I had the same problem today and I found that I have some customised logic in touchesEnded in one of collectionview's container views, and I didn't call
[super touchesEnded: withEvent:]
when I'm done with my customised logic in touchesEnded.
After adding the super call, everything is fine.
Select UITextView, in that specific case UICollectionViewCell, and switch to attribute inspector. The uncheck User interaction enabled and it should work fine.
I ran into this problem when I had a scroll view taking up my entire collection view cell. While all the solutions above probably work fine, I came up with my own elegant work-around. I put a 'select' label under my scroll view. Since the label is not part of the scroll view, it passes the tap event on to the collection view. It also serves as a nice indicator that an action is required of the user.
Just do this
textview.isUserInteractionEnabled = false
I have a scrollview, which automatically advances every 3 seconds to the next "page" (page control also used). However, once the user touches the scrollview, I want to stop the auto-advancing.
I have subclassed the scrollview. I can detect touchesBegan in the subclass, but touchesMoved is not called, so I can't tell if the user has manually swiped the scrollview. I can't use scrollviewDidScroll, because that gets called when I set the contentOffset when the auto-advance timer fires.
So what are my other options for detecting touches? Why isn't touchesMoved called on the scrollview subclass?
Thank you for the suggestions. They helped me stumble upon this easy solution:
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
[self.scrollTimer invalidate];
}
You may want to look into the following delegate method:
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView
Per Apple:
The scroll view calls this method at the end of its implementations of the UIScrollView and setContentOffset:animated: and scrollRectToVisible:animated: methods, but only if animations are requested.
So that delegate method is only called when programatic scrolling occurs. You could set up your autoscroll call in that method, only calling it if some BOOL is false. Setting that BOOL to true in your touch event.
Or something completely different =]
It is a useful delegate method though.
~ Good luck
The scrollview probably nominates a subview to receive touch input — UIKit objects are very fussy about this sort of thing and generally can't even handle forwarded events.
What you probably want to do is to key-value observe either tracking or dragging (and it sounds like you want the latter). If the relevant property changes to true then you know the user has initiated scrolling.
I have tried this a few different ways but none of them seem to work. I have a UIView subclass that has some buttons in it. I tried adding the subview to my ViewControllers however it will not respond to touches unless I set it to "initWithFrame:self.view.frame" but then it takes All of the touches and does not pass them to the view controller. I also tried adding it directly to the window so it's on top of all of the view however I have the same issue, either it will not accept touches or it takes them all.
here is how I add it when it takes all touches for itself and does not pass them on.
ControlView *cont = [[ControlView alloc]initWithFrame:self.window.frame];
[self.window addSubview:cont];
I'm so confused as to how to fix this and I have a lot more important tasks to work on but I have been stuck for two days with this stupid subview/touch issue.
How are you handling touches? UIGestureRecognizer?
You should make sure that your uiview subclass has userInteractionEnabled = YES. That's the default but maybe it got turned off somewhere along the line.
I have a root UIScrollView that only scrolls vertically, this scrollview represents rows in my jagged grid. I have configured this scroll view's pan gesture recognizer for two touches for both minimum and maximum number of touches requires.
Inside this scrollview I have one or more UIScrollView instances that only scrolls horizontally, these scrollviews each represent a single row in my jagged grid view. I have configured the pan gesture recognizers for all of these scroll views for one touch minimum, and two touches maximum.
So far it works, I get a nice jagged grid view where I can scroll vertically between rows, and horizontally to scroll each row independently. I have intentionally set to minimum number of touches as 2, as not to inter fear with scrolling if I add fro example a UITableView as a subview for any of cell within this jagged grid view (cell == a position defined by a row and column in that row).
Using a UITableView as a cell works, the table view works as expected that is. But scrolling with two fingers also scrolls inside the table view, not at the root scroll view for vertically scrolling between rows.
I have tried configuring the table views pan gesture recognizer to allow a maximum of one touches, in hope that two finger touches would be ignored. This does not work, the maximumNumberOfTouches property of the table view's pan gesture recognizer seams to be ignored.
What could I have done wrong?
A screen shot displaying the layout to clarify what I have done:
Multiple scrolling tends to get tricky, and I don't for sure, but I think Apple does not encourage this. Even so, I still think it's possible. It may be that vertical scrolling on the table view gets mixed with the scroll view vertical scrolling or something else.
Try checking if the delegates for the gesture recognizers are correctly set.
Another way around this is:
- having a Scroll view with buttons, from which you can open popovers with custom controllers (insert there whatever you want).
- create a big UITableViewController and setting the cell's contents as scrollviews etc. I think you could get the same result.
My advice is not to get stuck on just one method, when there could be others more simpler and more intuitive.
TableViews on Scroll views are generally not a great idea. When a TableView receives the touches, even if doesn't need to do anything with it, it won't send them to it's superView.
You might wanna try either of these 2 things:
In your TableView you should send the touches to your superView manually and let them handle them appropriately. I've seen this method being used in one of my side-projects but I'm not able to post an example of it at this time.
The second thing might be easier to implement. Since TableView is a subclass of ScrollView you can call upon the delaysContentTouches of those TableViews. This property will delay the touch-down even on that TableView until it can determine if scrolling is the intent, as is written in the AppleDocs: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIScrollView_Class/Reference/UIScrollView.html#//apple_ref/occ/cl/UIScrollView
Let me know if either of the 2 ways works for you, I'm quite curious about this subject generally.
But don't you try some tricks rather than implementing all such changes :
1) By Default, disable the scrolling of the TableView when the view is created.
2) Once the view gets generated, Recognize the gestures whether its Scrolling using single or multiple touches, if user touch the Child Scrollview.Look out the tag ,based on gestures, you can enable the Scrolling of Tableview.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//Get the tag of ScrollView
// Check for the Parent as well as Child SCrollview.
// If its child, just enable the scrolling of tableView.
}
- (void)tapAction:(UIGestureRecognizer *)gestureRecognizer
{
// CGPoint *poit = [Tile locationInView:gestureRecognizer.view];
/// [[[gestureRecognizers.view] objectAtIndex:0] removeFromSuperview];
// imageContent = [[UIImageView alloc]initWithFrame:CGRec tMake(0, 0, 200, 250)];
// [imageContent setImage:[UIImage imageNamed:#"Default.png"]];
NSLog(#"You tapped # this :%d",gestureRecognizer.view.tag);
//Regonize the gestures
}
There may be some unnecessary code since, there is no code snippet with your question.I gave a try & showed a trick if that could work for you & solve the problem. ;)
Try this link and pay attention to how they solve nested views.
Remember the best Practices for Handling Multitouch Events:
When handling events, both touch events and motion events, there are a few recommended techniques and patterns you should follow.
Always implement the event-cancellation methods.
In your implementation, you should restore the state of the view to what it was before the current multitouch sequence, freeing any transient resources set up for handling the event. If you don’t implement the cancellation method your view could be left in an inconsistent state. In some cases, another view might receive the cancellation message.
If you handle events in a subclass of UIView, UIViewController, or (in rare cases) UIResponder,
You should implement all of the event-handling methods (even if it is a null implementation).
Do not call the superclass implementation of the methods.
If you handle events in a subclass of any other UIKit responder class,
You do not have to implement all of the event-handling methods.
But in the methods you do implement, be sure to call the superclass implementation. For example,
[super touchesBegan:theTouches withEvent:theEvent];
Do not forward events to other responder objects of the UIKit framework.
The responders that you forward events to should be instances of your own subclasses of UIView, and all of these objects must be aware that event-forwarding is taking place and that, in the case of touch events, they may receive touches that are not bound to them.
Custom views that redraw themselves in response to events should only set drawing state in the event-handling methods and perform all of the drawing in the drawRect: method.
Do not explicitly send events up the responder (via nextResponder); instead, invoke the superclass implementation and let the UIKit handle responder-chain traversal.
In MonoTouch how do I get a UIImage or UIImageView to fire off a delegate or something when clicked?
Exactly as Dimitris pointed out, you'll want to subclass UIImageView, and also ensure that the userInteractionEnabled flag is set to true.
I should point out that in most cases where people intend to have a UIImageView respond to interaction, these problems can just as easily be fixed by creating a UIButton instance with an image instead.
You have to subclass it (the UIImageView) and override one of TouchesBegan, TouchesMoved or TouchesEnded methods, according to what you want to do.