Pretty simple question, perhaps not so simple answer though:
I've got a clear view which needs to receive touches. Underneath this is a UIButton, which I also want to receive touches (for reasons I won't go into, it has to be underneath). In the case where the button is pressed, I don't want the clear view to receive the touches.
How can I do this?
EDIT:
Final Solution:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
for (UIView * view in self.subviews)
{
if ([view isKindOfClass:[UIButton class]]) {
CGPoint pointInButton = [view convertPoint:point fromView:self];
if ([view pointInside:pointInButton withEvent:event]) {
return view;
}
}
}
return [super hitTest:point withEvent:event];
}
Give the clear view a reference to the UIButton. Override the clear view's pointInside:withEvent: method. In your override, check whether the point is inside the button (by sending pointInside:withEvent: to the button). If the point is in the button, return NO. If the point is outside the button, return [super pointInside:point withEvent:event].
Related
In my application i have a main screen, which has a subview (this is another screen), but this subview is moved 320 to the right so it is just offscreen. The effect is that the main screen moves 320 to the left, which hides the main screen and shows the other screen because it's a subview. The problem is, the other screen is not receiving touch events because it is out of the bounds of the main screen (superview). How do i get this other screen to also receive touch events so i can tap the buttons?
Have a look at this post on S.O. for an explanation. The solution is to implement your own hitTest using the following code:
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
BOOL isInside = [super pointInside:point withEvent:event];
// identify the button view subclass
UIButton *b = (UIButton *)[self viewWithTag:3232];
CGPoint inButtonSpace = [self convertPoint:point toView:b];
BOOL isInsideButton = [b pointInside:inButtonSpace withEvent:nil];
if (YES == isInsideButton) {
return isInsideButton;
} // if (YES == isInsideButton)
return isInside;
}
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
UIView *v = nil;
v = [super hitTest:point withEvent:event];
return v;
}
I have a UIView with 4 buttons on it and another UIView on top of the buttons view. The top most view contains a UIImageView with a UITapGestureRecognizer on it.
The behavoir I am trying to create is that when the user taps the UIImageView it toggles between being small in the bottom right hand corner of the screen and animating to become larger. When it is large I want the buttons on the bottom view to be disabled and when it is small and in the bottom right hand corner I want the touches to be passed through to the buttons and for them to work as normal. I am almost there but I cannot get the touches to pass through to the buttons unless I disable the UserInteractions of the top view.
I have this in my initWithFrame: of the top view:
// Add a gesture recognizer to the image view
UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(imageTapped:)];
tapGestureRecognizer.cancelsTouchesInView = NO;
[imageView addGestureRecognizer:tapGestureRecognizer];
[tapGestureRecognizer release];
and I this is my imageTapped: method:
- (void) imageTapped:(UITapGestureRecognizer *) gestureRecognizer {
// Toggle between expanding and contracting the image
if (expanded) {
[self contractAnimated:YES];
expanded = NO;
gestureRecognizer.cancelsTouchesInView = NO;
self.userInteractionEnabled = NO;
self.exclusiveTouch = NO;
}
else {
[self expandAnimated:YES];
expanded = YES;
gestureRecognizer.cancelsTouchesInView = NO;
self.userInteractionEnabled = YES;
self.exclusiveTouch = YES;
}
}
With the above code, when the image is large the buttons are inactive, when I touch the image it shrinks and the buttons become active. However, the small image doesn't receive the touches and therefore wont expand.
If I set self.userInteractionEnabled = YES in both cases, then the image expands and contracts when touched but the buttons never receive touches and act as though disabled.
Is there away to get the image to expand and contract when touched but for the buttons underneath to only receive touches if the image is in its contracted state? Am I doing something stupid here and missing something obvious?
I am going absolutely mad trying to get this to work so any help would be appreciated,
Dave
UPDATE:
For further testing I overrode the touchesBegan: and touchesCancelled: methods and called their super implementations on my view containing the UIImageView. With the code above, the touchesCancelled: is never called and the touchesBegan: is always called.
So it would appear that the view is getting the touches, they are just not passed to the view underneath.
UPDATE
Is this because of the way the responder chain works? My view hierarchy looks like this:
VC - View1
-View2
-imageView1 (has tapGestureRecogniser)
-imageView2
-View3
-button1
-button2
I think the OS first does a hitTest as says View2 is in front so should get all the touches and these are never passed on to View3 unless userInteractions is set to NO for View2, in which case the imageView1 is also prevented from receiving touches. Is this how it works and is there a way for View2 to pass through it's touches to View3?
The UIGestureRecognizer is a red herring I think. In the end to solve this I overrode the pointInside:withEvent: method of my UIView:
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
BOOL pointInside = NO;
if (CGRectContainsPoint(imageView.frame, point) || expanded) pointInside = YES;
return pointInside;
}
This causes the view to trap all touches if you touch either the imageView or if its expanded flag is set. If it is not expanded then only trap the touches if they are on the imageView.
By returning NO, the top level VC's View queries the rest of its view hierarchy looking for a hit.
Select your View in Storyboard or XIB and...
Or in Swift
view.isUserInteractionEnabled = false
Look into the UIGestureRecognizerDelegate Protocol. Specifically, gestureRecognizer:shouldReceiveTouch:
You'll want to make each UIGestureRecognizer a property of your UIViewController,
// .h
#property (nonatomic, strong) UITapGestureRecognizer *lowerTap;
// .m
#synthesize lowerTap;
// When you are adding the gesture recognizer to the image view
self.lowerTap = tapGestureRecognizer
Make sure you make your UIViewController a delegate,
[self.lowerTap setDelegate: self];
Then, you'd have something like this,
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
if (expanded && gestureRecognizer == self.lowerTap) {
return NO;
}
else {
return YES;
}
}
Of course, this isn't exact code. But this is the general pattern you'd want to follow.
I have a another solution. I have two views, let's call them CustomSubView that were overlapping and they should both receive the touches. So I have a view controller and a custom UIView class, lets call it ViewControllerView that I set in interface builder, then I added the two views that should receive the touches to that view.
So I intercepted the touches in ViewControllerView by overwriting hitTest:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
return self;
}
Then I overwrote in ViewControllerView:
- (void)touchesBegan:(NSSet *)touches
withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];
for (UIView *subview in [self.subviews reverseObjectEnumerator])
{
if ([subview isKindOfClass:[CustomSubView class]])
{
[subview touchesBegan:touches withEvent:event];
}
}
}
Do the exact same with touchesMoved touchesEnded and touchesCancelled.
#Magic Bullet Dave's solution but in Swift
Swift 3
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
var pointInside = false
if commentTextField.frame.contains(point) {
pointInside = true
} else {
commentTextField.resignFirstResponder()
}
return pointInside
}
I use it in my CameraOverlayView for ImagePickerViewController.cameraOverlay to give user ability to comment while taking new photo
I have a scroll view that is 256x256 in width/height. I have subviews of that scroll view stretching in both directions (left and right). I set clipToBounds to NO so I can see the items in the scroll view.
When the user touches a space in the scrollview holder (the area that extends beyond the 256x256) I check the hittest and return the scrollView.
My problem is the items on my scrollview are buttons, and if the button is not inside the 256x256 it is not receiving the touch events. How do I cycle through the buttons on the scrollview and then forward the events to the buttons?
I'm doing like this Paging UIScrollView with peeking neighbor pages
But my scrollview subviews aren't receiving events.
I've tried all of the following in my view that is supposed to send events down the wire and my buttons will not receive the events. The event chain always stops at my UIScroll view - allowing me to scroll my items - but how do I forward events to the buttons from the scrollview?
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if ([self pointInside:point withEvent:event]) {
return self.scrollView;
}
return nil;
}
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if ([self pointInside:point withEvent:event]) {
return self.scrollView;
}
return nil;
}
- (UIView *) hitTest:(CGPoint) point withEvent:(UIEvent *)event {
UIView* child = nil;
if ((child = [super hitTest:point withEvent:event]) == self) {
return self.scrollView;
}
return child;
}
This was the answer and better solution. Instead of having the arbitrary view to forward events, we just do this in the UIScrollView and all the buttons and swipes work fine.
- (UIView )hitTest:(CGPoint)point withEvent:(UIEvent )event {
UIView *view = [super hitTest:point withEvent:event];
for (UIView *subview in self.subviews) {
if (view != nil && view.userInteractionEnabled) {
break;
}
CGPoint newPoint = [self convertPoint:point toView:subview];
view = [subview hitTest:newPoint withEvent:event];
}
return view;
}
Did you override the UIScrollView's hitTest?
- (UIView*)hitTest:(CGPoint)pt withEvent:(UIEvent*)event
{
UIView *contentView = [self.subviews count] ? [self.subviews objectAtIndex:0] : nil;
return [contentView hitTest:pt withEvent:event];
}
See the section Detecting Touches Outside a Scroll View in Matt Galloway's tutorial How To Use UIScrollView to Scroll and Zoom Content -
You make the scroll view smaller than the screen and with Clip Subviews unchecked:
And wrap it into a container view, which forwards events to the scroll view:
- (UIView*)hitTest:(CGPoint)point withEvent:(UIEvent*)event {
UIView *view = [super hitTest:point withEvent:event];
if (view == self) {
return _scrollView;
}
return view;
}
your scrollview should be bigger.
All events outside the main scrollview's frame will not be detected.
If you need to show the user a specific background zone, then put your scrollview's background transparent and put another view behind.
I have UIViewControllerand UITableView as child in the view,
what I want to do is when I touch any row I am displaying a view at bottom. I want to hide that view if the user touch any where else then rows or the bottomView.
The problem is when I click on UITableView it doesn't fires touchesEnded event.
Now how can I detect touch on UITableView and distinguish it with row selection event.
Thanks.
No need to subclass anything, you can add a UITapGestureRecognizer to the UITableView and absorb the gesture or not depending on your criteria.
In your viewDidLoad:
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTapOnTableView:)];
[self.myTableView addGestureRecognizer:tap];
Then, implement your action like this for the criteria:
-(void) didTapOnTableView:(UIGestureRecognizer*) recognizer {
CGPoint tapLocation = [recognizer locationInView:self.myTableView];
NSIndexPath *indexPath = [self.myTableView indexPathForRowAtPoint:tapLocation];
if (indexPath) { //we are in a tableview cell, let the gesture be handled by the view
recognizer.cancelsTouchesInView = NO;
} else { // anywhere else, do what is needed for your case
[self.navigationController popViewControllerAnimated:YES];
}
}
And note that if you just want to simply pick up clicks anywhere on the table, but not on any buttons in cell rows, you need only use the first code fragment above. A typical example is when you have a UITableView and there is also a UISearchBar. You want to eliminate the search bar when the user clicks, scrolls, etc the table view. Code example...
-(void)viewDidLoad {
[super viewDidLoad];
etc ...
[self _prepareTable];
}
-(void)_prepareTable {
self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
self.tableView.allowsSelection = NO;
etc...
UITapGestureRecognizer *anyTouch =
[[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(tableTap)];
[self.tableView addGestureRecognizer:anyTouch];
}
// Always drop the keyboard when the user taps on the table:
// This will correctly NOT affect any buttons in cell rows:
-(void)tableTap {
[self.searchBar resignFirstResponder];
}
// You probably also want to drop the keyboard when the user is
// scrolling around looking at the table. If so:
-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
[self.searchBar resignFirstResponder];
}
// Finally you may or may not want to drop the keyboard when
// a button in one cell row is clicked. If so:
-(void)clickedSomeCellButton... {
[self.searchBar resignFirstResponder];
...
}
Hope it helps someone.
You should forward the touch event to the view's controller.
Subclass your tableview control and then override the method:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event]; //let the tableview handle cell selection
[self.nextResponder touchesBegan:touches withEvent:event]; // give the controller a chance for handling touch events
}
then , you can do what you want in the controller's touch methods.
I just stumbled onto what may be a solution for your problem. Use this code when you create your table view:
tableView.canCancelContentTouches = NO;
Without setting this to NO, the touch events are cancelled as soon as there is even a slight bit of vertical movement in your table view (if you put NSLog statements in your code, you'll see that touchesCancelled is called as soon as the table starts scrolling vertically).
I was facing the problem since a long time and didn't got any working solution. Finally I choose to go with a alternative. I know technically this is not the solution but this may help someone looking for the same for sure.
In my case I want to select a row that will show some option after that I touch anywhere on table or View I want to hide those options or do any task except the row selected previously for that I did following:
Set touch events for the view. This will do the task when you touch anywhere on the view except the table view.
TableView's didSelectRowAtIndexPath do following
- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath {
if(indexPath.row != previousSelectedRow && previousSelectedRow != -1) {
// hide options or whatever you want to do
previousSelectedRow = -1;
}
else {
// show your options or other things
previousSelectedRow = indexPath.row;
}
}
I know that this is older post and not a good technical solution but this worked for me. I am posting this answer because this may help someone for sure.
Note: The code written here may have spell mistakes because directly typed here. :)
Try this methods:
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
}
Use scrollViewDidEndDragging like alternative of touchesEnded. Hope it helps.
To receive touch events on the UITableView use:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//<my stuff>
[super touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
//<my stuff>
[super touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
//<my stuff>
[super touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event
{
//<my stuff>
[super touchesCancelled:touches withEvent:event];
}
In your controller class declare a method which removes the bottom view. Something like this:
-(IBAction)bottomViewRemove:(id)sender {
[bottomView removeFromSuperview];
}
In Interface Builder, select your view and in the identity inspector in the custom class section, change the class from UIView to UIControl. After that go to the connections inspector and connect the TouchUpInside event to the method declared above. Hope this helps.
I've seen some threads about how to dismiss the Keyboard when a UITextField loses focus, but it did not work for me and I don't know how. The "touchesBegan:withEvent:" in the following code, never gets called. Why?
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
if ([self.textFieldOnFocus isFirstResponder] && [touch view] != self.textFieldOnFocus) {
[textFieldOnFocus resignFirstResponder];
}
[super touchesBegan:touches withEvent:event];
}
P.S.: This code has been inserted in the view controller which has a UITableView. The UITextField is in a cell from this table.
So, my opinion is: this method is not being called, cause the touch occurs on the UITableView from my ViewController. So, I think, that to I should have to subclass the UITableView, to use this method as I have seen on other Threads, but it may have a easier way.
Could you please help me? Thanks a lot!
Make sure you set the delegate of the UITextField to First Responder in IB. And I just put a custom (invisible) UIButton over the screen and set up an IBAction to hide the keyboard. Ex:
- (IBAction)hideKeyboard {
[someTextField resignFirstResponder];
}
With that hooked up to a UIButton.
Here is my solution, somewhat inspired by several posts in SO: Simply handle the tap gesture in the context of the View, the user is 'obviously' trying to leave the focus of the UITextField.
-(void)handleViewTapGesture:(UITapGestureRecognizer *)gesture
{
[self endEditing:YES];
}
This is implemented in the ViewController. The handler is added as a gesture recognizer to the appropriate View in the View property's setter:
-(void) setLoginView:(LoginView *)loginView
{
_loginView = loginView;
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self.loginView action:#selector(handleTapGesture:)];
[tapRecognizer setDelegate:self]; // self implements the UIGestureRecognizerDelegate protocol
[self.loginView addGestureRecognizer:tapRecognizer];
}
The handler could be defined in the View as well. If you are unfamiliar with handling gestures, see Apple's docs are tons of samples elsewhere.
I should mention that you will need some additional code to make sure other controls get taps, you need a delegate that implements the UIGestureRecognizerDelegate protocol and this method:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
if ([touch.view isKindOfClass:[UIButton class]]) // Customize appropriately.
return NO; // Don't let the custom gestureRecognizer handle the touch
return YES;
}
-(void)touchesEnded: (NSSet *)touches withEvent: (UIEvent *)event
{
for (UIView* view in self.view.subviews)
{
if ([view isKindOfClass:[UITextField class]])
[view resignFirstResponder];
}
}