Basically...
I have a UIScrollView subclass which you can add a target and selector too, which get fired if a touch event is detected within the view. I am using the scroll view as an image gallery, and the touch inside the scroll view is used to fade out the HUD components (UItoolBar, etc):
#implementation TouchableScrollView
- (void)addTarget:(id)_target withAction:(SEL)_action
{
target = _target;
action = _action;
shouldRun = NO;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
shouldRun = YES;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
shouldRun = NO;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
if(shouldRun)
{
shouldRun = NO;
[target performSelector:action];
}
}
#end
I then have another custom UIView added as a subview to this which has the following set (both of which I have played around with):
self.userInteractionEnabled = YES;
self.exclusiveTouch = YES;
and uses the following to trigger an animation:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
The problem is even when the custom UIView detects the touch and responds (by flipping itself over), the UIScrollView selector also gets fired causing everything to fade out.
Please help, I'm totally stuck?!
better to use this in custom ScrollView class
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
if (!self.dragging) {
[self.nextResponder touchesEnded: touches withEvent:event];
}
[super touchesEnded: touches withEvent: event];
self.nextResponder is scrollView subViews. so event other then dragging (scrolling) will be handled by your main viewController . in main View controller inherit touch event method. there u can check for touch event for particular view or image view.
Related
I am trying to detect touches inside a subview
In my main viewcontroller I am adding a subview called:SideBarForCategory, it takes 30% of the screen from the left - as a sidebar.
SideBarForCategory *sideBarForCategory = [[SideBarForCategory alloc] initWithNibName:#"SideBarForCategory" bundle:nil];
[sideBarData addSubview:sideBarForCategory.view];
inside SideBarForCategory, I would like to test for touches
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event touchesForView:self.view] anyObject];
CGPoint location = [touch locationInView:touch.view];
NSLog(#"Map Touch %f",location.x);
}
The above code (touchesMoved) works perfectly on the main view (viewcontroller) but does not work inside my subview (SideBarForCategory) - why and how can I fix it?
Two possible solutions i can think of :
Either use GestureRecognizers (eg. UITapGestureRecognizer, UISwipeGestureRecognizer) and add those recognizers to your SideBarForCategory view.
Generic gesture handling : Create your own custom subclass of UIView for example MyView and add those touch methods inside it. Then create SideBarForCategory view as an instance of MyView.
Hope it works :)
Updated :
For second option :
#import <UIKit/UIKit.h>
#interface MyView : UIView
#end
#implementation MyView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
// No need to invoke |touchesBegan| on super
NSLog(#"touchesBegan");
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
// invoke |touchesMoved| on super so that scrolling can be handled
[super touchesMoved:touches withEvent:event];
NSLog(#"touchesMoved");
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesEnded:touches withEvent:event];
NSLog(#"touchesEnded");
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
/* no state to clean up, so null implementation */
NSLog(#"touchesCancelled");
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end
Update :
And then in your SideBarCategoryView class implementation , inside loadView()
self.view = [[MyView alloc] init];
check Apple's references for converting points. You probably forget to convert the point relevant to your subview. Therefore it is trying to check the absolute coordinates of the touch point.
Probably what you need is :
- (CGPoint)convertPoint:(CGPoint)point toView:(UIView *)view
I am handling touches for a couple of my UI components in my view controller (custom subclass of UIViewController). It has methods touchesBegan:withEvent:, touchesMoved:withEvent:, and touchesEnded:withEvent:. It was working fine. Then I added a scroll view (UIScrollView) as the top view in the hierarchy.
Now my touch handlers on the view controller don't work. They don't get called. The interesting thing is, I have various other UI components within the scroll view that do work. Some are buttons, some are custom views that define their own touchesBegan:withEvent:, etc. The only thing that doesn't work is the touch handlers on the view controller.
I thought maybe it's because the scroll view is intercepting those touches for its own purposes, but I subclassed UIScrollView and just to see if I could get it to work I am returning YES always from touchesShouldBegin:withEvent:inContentView: and NO always from touchesShouldCancelInContentView:. Still doesn't work.
If it makes a difference my view controller is within a tab bar controller, but I don't think it's relevant.
Has anyone had this problem and have a ready solution? My guess is the scroll view monkeys up the responder chain. Can I monkey it back? I guess if I can't figure anything else out I'll make the top level view under my scroll view be a custom view and forward the messages on to the view controller, but seems kludgy.
create a subclass of UIScrollView class and override the touchesBegan: and other touch methods as follows:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesBegan: touches withEvent:event];
}
else{
[super touchesBegan: touches withEvent: event];
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesMoved: touches withEvent:event];
}
else{
[super touchesMoved: touches withEvent: event];
}
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
// If not dragging, send event to next responder
if (!self.dragging){
[self.nextResponder touchesEnded: touches withEvent:event];
}
else{
[super touchesEnded: touches withEvent: event];
}
}
Well this worked, but I'm not sure I can "get away with it", since nextResponder is not one of the UIView methods you're "encouraged" to override in a subclass.
#interface ResponderRedirectingView : UIView {
IBOutlet UIResponder *newNextResponder;
}
#property (nonatomic, assign) IBOutlet UIResponder *newNextResponder;
#end
#implementation ResponderRedirectingView
#synthesize newNextResponder;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
- (UIResponder *)nextResponder {
return self.newNextResponder;
}
- (void)dealloc
{
[super dealloc];
}
#end
Then in Interface Builder I made the direct subview of the scroll view one of these, and hooked up its newNextResponder to skip the scrollview and point directly to the view controller.
This works too, replacing the override of nextResponder with these overrides:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesBegan:touches withEvent:event];
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesMoved:touches withEvent:event];
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[self.newNextResponder touchesCancelled:touches withEvent:event];
}
"It was working fine. Then I added a scroll view (UIScrollView) as the top view in the hierarchy."
is your scrollview on top of your contentview that contains items?
all your components should be in the scrollview and not the view behind the scrollview
user1085093's answer worked for me. Once you move the touch more than a small amount, however, it then gets interpreted as a Pan Gesture.
I overcame this by altering the behaviour of the Pan Gesture recogniser so it requires two fingers:
-(void)awakeFromNib
{
NSArray *gestureRecognizers = self.gestureRecognizers;
UIGestureRecognizer *gestureRecognizer;
for (gestureRecognizer in gestureRecognizers) {
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer *pgRecognizer = (UIPanGestureRecognizer*)gestureRecognizer;
pgRecognizer.minimumNumberOfTouches = 2;
}
}
}
The touchesBegan: etc methods will NEVER be called in a UIScrollView because it is a subclass of UIView and overrides these methods. check out the different UIScrollView methods available here. The work-around will depend on what you want to implement.
I want to make a transparent mask-view over the current window, which just tracks touch events and passing them to the visible views below. However if I set userInteractionEnabled=YES to this mask, this blocks the events and won't be passed below.
Is there any way that I can prevent this view from blocking the events, or manually passing the events below?
Thanks,
I just recently did this for one of my apps and it turned out to be quite simple.
Get ready to subclass UIView:
I called my Mask View the catcher view and this is how the protocol looks:
#interface CatcherView : UIView {
UIView *viewBelow;
}
#property(nonatomic,retain)UIView *viewBelow;
#end
Here you are just subclassing UIView AND keeping a reference to the view bellow.
On the implementation you need to fully implement at least 4 methods to pass the touches to the view, or views bellow, this is how the methods look:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Began");
[self.viewBelow touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Moved");
[self.viewBelow touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Ended");
[self.viewBelow touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touch Cancelled");
//Not necessary for my app but you just need to forward it to your view bellow.
}
Just remember to set the view or views that are bellow when you create the view; it is also very important to set the background color to clear, so it acts as a mask. THis is how that looks:
CatcherView *catchView=[[CatcherView alloc] initWithFrame:[self.view bounds]];
catchView.backgroundColor=[UIColor clearColor];
catchView.viewBelow=myViewBellow;
[self.view addSubview:catchView];
Hope it helps and comment if you need more info.
UIKit determines the target view for an event by sending -hitTest:withEvent: messages down the responder chain
Once the target has been found, the event is sent up the responder chain until a responder that handles it is found (often the view that was touched, but not always)
Thus, if you override -[NSView hitTest:withEvent:] in a suitably high up view (perhaps by using a custom window!) you can note all incoming events and call super to have them behave as normal.
I wish to drag from one subview to another within my application (and connect them with a line), and so I need to keep track of the current view being touched by the user.
I thought that I could achieve this by simply calling [UITouch view] in the touchesMoved method, but after a quick look at the docs I've found out that [UITouch view] only returns the view in which the initial touch occurred.
Does anyone know how I can detect the view being touched while the drag is in progress?
And my way:
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
if ([self pointInside:[touch locationInView:self] withEvent:event]) {
[self sendActionsForControlEvents:UIControlEventTouchUpInside];
} else {
[self sendActionsForControlEvents:UIControlEventTouchUpOutside];
}
}
After a bit more research I found the answer.
Originally, I was checking for the view like so:
if([[touch view] isKindOfClass:[MyView* class]])
{
//hurray.
}
But, as explained in my question, the [touch view] returns the view in which the original touch occurred. This can be solved by replacing the code above with the following:
if([[self hitTest:[touch locationInView:self] withEvent:event] isKindOfClass:[MyView class]])
{
//hurrraaay! :)
}
Hope this helps
UIView is subclass of UIResponder. So you can override touches ended/ began methods in your custom class, that inherits from UIView. Than you should add delegate to that class and define protocol for it. In the methods
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
or whatever interactions you need just send appropriate message to object's delegate also passing this object. E.g.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[delegate touchesBeganInView: self withEvent: event];
}
I'm wondering how to track touches anywhere on the iPhone screen and still have UIButtons respond to taps.
I subclassed a UIView, made it full screen and the highest view in the hierarchy, and overrode its pointInside:withEvent method. If I return YES, I'm able to track touches anywhere on the screen but the buttons don't respond (likely because the view is instructed to handle and terminate the touch). If I return NO, the touch passes through the view and the buttons respond, but I'm not able to track touches.
Do I need to subclass UIButton or is this possible through the responder chain? What am I doing wrong?
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event{
return NO;
}
//only works if pointInside:withEvent: returns YES.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
NSLog(#"began");
[self.nextResponder touchesBegan:touches withEvent:event];
}
//only works if pointInside:withEvent: returns YES.
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
NSLog(#"end");
[self.nextResponder touchesEnded:touches withEvent:event];
}
Rather then having extra view you can subclass your applications main window and track touches (and other events in it)
#interface MyAppWindow : UIWindow
...
#implementation MyAppWindow
- (void)sendEvent:(UIEvent*)event {
[super sendEvent:event];
if (event.type == UIEventTypeTouches){
// Do something here
}
return;
}
Then set your application window type to MyAppWindow (I did that in MainWindow.xib in IB)