I am just getting stated with iPhone development and can't seem to find the answer I am looking for what I want to do.
It seems like I should be able to programmatically create a UIImageView and then set up an event handler for it's touch functions.
in c# i would have something that looks like
Button b = new Button();
b.Click+= my handler code
right now I have this
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 141.0f, 151.0f);
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
myImage.userInteractionEnabled = YES;
[myImage setImage:[UIImage imageNamed:#"myImage.png"]];
myImage.opaque = YES; // explicitly opaque for performance
[self.view addSubview:myImage];
[myImage release];
What do I need to do to override the touch events?
thanks
While it is not the complete answer to your question, i think the following solution might be better then doing the "invisible-button-workaround"..
simply subclass from UIImageView and override the following method:
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
//your UIImageView has been touched :)
//event -> "A UIEvent object representing the event to which the touches belong."
//touches -> "A set of UITouch instances in the event represented by event that represent the touches in the UITouchPhaseEnded phase."
}
hope this helps...
I have a mainview with some icons like "about" to open an about view.
In the corresponding controller (mainview) I added an event handler for touchesBegan.
Moreover I need to check which view has been "touched", as there are more icons on the view.
My UIImageView instance is "aboutImg" and user interaction needs to be checked (i.e. UI builder -> attributes inspector of view).
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
if ([touch view] == aboutImg){
[self ShowAbout];
}
}
Make sure you check the "User Interactions enabled". This is the easiest solution
Just use a custom UIButton with the image as background image.
I've not found a way to do it directly with UIImageView. But if you subclass it and override the nextResponder method to return a delegate under your control you can do what you're after. Expose the delegate as a property of the subclass and then you can pass in a delegate for the touch events and change it at any time.
I've seen other answers suggest putting an invisible button underneath the UIImageView, setting the image view to userInteractionEnabled: NO, and letting the touches pass through to the button.
You need nothing to do with UIImageView, You can use UIButton with type custom and add touch up inside action to it...set button.imageview setImage:
i-e:
UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(0,0,100,100); //edit for you own frame
UIImage *img = [UIImage imageNamed:#"myimage.png"];
[button setImage:img forState:UIControlStateNormal];
If you want to go with UIImageView, then you need to add gestures to your imageview. else you can subclass your UIImageView and then use touch events.
Easiest way to add an onClick event to an UIImageView or to a UIView is to add a tap gesture recognizer to it.
UIImage *myImage = [UIImage imageNamed:#"myImage.png"];
UIImageView *myImageView = [[UIImageView alloc] initWithImage: myImage];
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action: #selector(onImageViewClicked)];
singleTap.numberOfTapsRequired = 1;
singleTap.numberOfTouchesRequired = 1;
[self.myImageView addGestureRecognizer:singleTap];
[self.myImageView setUserInteractionEnabled:YES];
Related
How can i select image on tapped gesture. I want to add another image same as I have tapped on . If i have 3 images and if I have tapped 2nd one then it will dynamically add 4th image that will be same as 2nd one.
UIImage *image = [[info objectForKey:#"UIImagePickerControllerOriginalImage"] retain];
UIView *holderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, image.size.width/4, image.size.height/4)];
UIImageView *imageview = [[UIImageView alloc] initWithFrame:[holderView frame]];
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapped:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setDelegate:self];
[holderView addGestureRecognizer:tapRecognizer];
-(void)tapped:(id)sender {
[[[(UITapGestureRecognizer*)sender view] layer] removeAllAnimations];
NSLog(#"Tapped");
[self.view bringSubviewToFront:[(UITapGestureRecognizer*)sender view]];
UIImageView *image = (UIImageView *)[(UITapGestureRecognizer*)sender view];
[self.view addSubview:image];
}
I am using [(UITapGestureRecognizer*)sender view]] to get that view. But I cant. And on tapped I want to add that image which I have tapped.
The issue is with your tapped method. When you write (UIImageView *)[(UITapGestureRecognizer*)sender view]; you'll get the same added imageView and it's frame will be same as when it was added. You are then adding it using addSubview, If you do so it'll be added at the same position that it was added previously.
Just change your tapped like:
-(void)tapped:(id)sender
{
[[[(UITapGestureRecognizer*)sender view] layer] removeAllAnimations];
UIImageView *imgView = (UIImageView *)[(UITapGestureRecognizer*)sender view];
UIImageView *imageview = [[UIImageView alloc] initWithFrame:yourFrame]; //Set the next frame for the image view
imageView.image = imgView.image;
[self.view addSubview:imageView];
[imageView release];
imageView = nil;
}
Also add the gesture to UIImageView like:
[imageview addGestureRecognizer:tapRecognizer]; not to UIView.
Also set imageview.userInteractionEnabled = YES;
3 Problems:
You need a new UIImageView which holds the same UIImage, as Jon Rose pointed out.
You need to set the frame for the new UIImageView, like Midhun MP pointed out.
Both do miss the gesture recognizer logic, which is broken in your case, too. You can add a gesture recognizer to only one view at a time.
To solve 3, You either need (a) one recognizer for each UIImageView, or
(b) you take one recognizer for the containing view, which is self in your case.
In case (a) you really should subclass UIImageView and implement the gesture handling there. In case (b), you'd add the recognizer to self and on the tapped: event you'd loop over the subviews to find the one that was tapped via
for(UIView* subject in self.subviews)
{
CGPoint pointInSubjectsView = [recognizer locationInView:subject];
BOOL pointInsideObject = [subject pointInside:pointInSubjectsView withEvent:nil];
if(pointInsideObject){
//subject is the tapped view. do the work...
}
}
Your code suggests that you are doing animations which you want to cancel on tap and that the images may overlap and you want to bring the tapped image to the front? If this is the case, you probably should go with (a).
Good luck.
You seem to be confusing a UIImage with a UIImageView. A UImageView is a kind of UIView and can have one (and only one) superview. If you want to know what image it holds you can use the 'image' property. Then you can create a new UIImageView with the same UIImage as the one that tapped. Depending on your application you may need to resize its frame, and set it contentMode.
In any event, if the tap event is not being registered at all it is likely because UIImageView are by default userInteractionEnabled=NO, you must explicitly set it to be YES either in code, or in the XIB file.
I use a UIScrollView to show a serial of UIImageView(the UIImageView is added as subview of scrollview), the problem is that I have rewrote the method in UIImageView:
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
But when I click the image , the method is not called, it seems that the image did not receive the click event. What is the exact reason? How can I fix this?
(I have enable the exclusiveTouch of the UIImageView and the User Interavtion of all the view)
Set the UIImageView's exclusiveTouch and userInteractionEnabled properties to YES and try again. I find that subviews of scrollview's receive only some or no events, and setting exclusiveTouch allows the view to claim them immediately.
set
imageView.userInteractionEnabled = YES;
and if you just want a tap event for the imageview
just use the UITapGestureRecognizer
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tap:)];
[imageView addGestureRecognizer:tap];
then you must implement the method
- (void) tap:(UITapGestureRecognizer*)gesture
{
UIImageView *v = gesture.view;// that your ImageView tapped
}
imageView.userInteractionEnabled = NO;
I have a scrollView onto which some imageViews are added.
I want that when scrollView scrolls then also the imageViews should get touch events.
But it is not happening in my case.
Only one of the two things happen at a time.
Either the scrollView scrolls but the imageViews do not get touch events
or the imageViews get touch events and the scrollView does not get scrolled.
Can't both of the things happen simultaneously.
Please suggest.
You can use "Tap Gesture Recognizer" to get the events on your images while it's being added to the scroll view.
EDIT
You can refer to this code:
-(void)yourGestureRecognizer
{
UITapGestureRecognizer *yourTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
[yourImageView addGestureRecognizer:yourGestureRecognizer];
[yourGestureRecognizer release];
}
You can handle tap here:
-(void)handleTap:(UIGestureRecognizer *)sender{
UIImageView *imageView = (UIImageView *)sender.view;
switch (imageView.tag)
{
case 1:
m_pYourInstance=[[ViewController alloc]initWithNibName:#"ViewController" bundle:nil];
[self.navigationController pushViewController:XXXXX animated:YES];
break;
}
Hope this helps !!
I know this was posted a while ago, but...
By default, UIImageView objects have their property userInteractionEnabled set to NO. This could be why touches aren't registering. This has tripped me up on more than one occasion and it's one of those little things that only experience will help.
Set it to YES and see if that fixes it.
Use UIGestureRecognizer. Add the recognizer to your image views.
And if you are targeting some old iOS version, have a look at this link.
yes you can do both. you need to customize your uiimageview by sub classing it and have to add Tap Gesture Recognizer like :
in .h file
#interface CustomView : UIImageView
{
// your variables
}
in .m file
//when you create an instants of your image view UITapGestureRecognizer will added in all your instants.
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame]))
{
// add Gesture for tapping
UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(tap:)];
tap.numberOfTapsRequired = 1;
[self addGestureRecognizer:tap];
}
return self;
}
then add delegate methods in .m file too
- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
UITouch *touch = [touches anyObject];
}
now in your custom cell, add your custom image view with Tap Gesture Recognizer
hope it will help you...
Use UIButtons with background images set on them. Here's the loop you use to layout UIScrollView subviews:
for (int i = 0; i < [images count]; i++) {
CGRect aFrame = ...;
UIButton *button = [[[UIButton alloc] initWithFrame:aFrame] autorelease];
[button setImage:[images objectAtIndex:i] forState:UIControlStateNormal];
button.tag = i;
[button addTarget:self action:#selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[scrollView addSubview:button];
}
And here you process the touch event:
- (void)buttonClicked:(id)sender {
UIButton *button = (UIButton *)sender;
[self performActionWithImageAtIndex:[images objectAtIndex:button.tag]];
}
That will omit the need to create additional gesture recognizers and will lower the amount of boilerplate work.
-- edit
The other reason your UIImageViews are not detecting the touches is because you create them in code and forget to set userInteractionEnabled to YES.
I m using UIimageview on top of UIWindow. I want to handle touch event for that Imageview, but m not able to do it.
When i use UIimageView on UIview, we can use touchBegan, touchEnded but how to handle it when it is on UIWindow instead of UIView.
Thanks..
If you just want to handle the tap, you have to set,
imageView.userInteractionEnabled = YES;
By default UIImageView has the userInteractionEnabled property set to NO. And you can add a tap gesture recognizer to it,
UITapGestureRecognizer *tgr = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(anyMethod)];
[imageView addGestureRecognizer:tgr];
[tgr release];
If you want to move the image, you can use UIPanGestureRecognizer.
- (void)sendEvent:(UIEvent *)event
try this function
Hola guys.
I'm experiencing a little problem with touch handling and UIResponder.
My goal is to manage a single touch (moved) to interact with different views.
I added a gesture recognizer to my UIImageView that send a simple message to my customViewController. It allocate and display a custom view (subclassing a UIButton) over the tapped UIImageView.
I would be able (without have to release the initial finger tap) to send touch movement to my new allocated custom button.
It seems that my UIImageView swallow my touch and so my new Button can't feel the finger movement.
I tried to resign first responder but it seems having no effect.
My custom Button work pretty good but only if I release the first tap and then tap again over the new displayer button.
Any suggests?
Thank you in advance.
Some code here:
Inside my viewController I attached a longPressGestureRecognizer to my profileImageView that draw a circular button surrounding the profileImageView.
-(void)showMenu:(UIGestureRecognizer*)gesture {
[profileImageView removeGestureRecognizer:gesture];
[profileImageView setUserInteractionEnabled:NO];
ConcentricRadius radius;
radius.externalRadius = 75;
radius.internalRadius = 45;
GTCircularButton *circularMenu = [[[GTCircularButton alloc] initWithImage:[UIImage imageNamed:#"radio.png"] highlightedImage:[UIImage imageNamed:#"radio_selected.png"] radius:radius] autorelease];
[circularMenu setTag:kCircularTagControllerCircularMenu];
[circularMenu setCenter:[profileImageView center]];
// Buttons' frames will be set up by the circularMenu
UIButton *button1 = [[[UIButton alloc] init] autorelease];
UIButton *button2 = [[[UIButton alloc] init] autorelease];
UIButton *button3 = [[[UIButton alloc] init] autorelease];
UIButton *button4 = [[[UIButton alloc] init] autorelease];
[circularMenu setButtons:[NSArray arrayWithObjects:button1, button2, button3, button4, nil]];
//[[self view] addSubview:circularMenu];
[[self view] insertSubview:circularMenu belowSubview:profileImageView];
}
Now I handle manually the touchEvent inside the circularMenu using the touchMoved methods.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
CGPoint touchLocation = [(UITouch*)[touches anyObject] locationInView:self];
for (UIView *aSubview in _roundButtons) {
if ([aSubview isKindOfClass:[UIButton class]]) {
UIButton *aButton = (UIButton*)aSubview;
CGPoint buttonTouchPointConverted = [aButton convertPoint:touchLocation toView:aButton];
if (CGRectContainsPoint([[aButton layer] frame], buttonTouchPointConverted)) {
[self rotateHighlightImage:aButton];
}
}
}
}
The goal is always to handle the end of gestureRecognizer and pass the touch event to the new instance created without having to lift my finger from the screen.
Any ideas?
PD: I handle touch manually with touchMoved cause if I use the addTarget:action:forControlEvents: on my buttons (1,2,3, and 4) the button that detect touchEvent swallow it and make other buttons impossible to feel the touch moving over them.
Your touchesEnded:withEvent: will have to be the same as your touchesMoved:withEvent: except it must invoke the method which is probably tied to the control event Touch Up Inside event.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
CGPoint touchLocation = [(UITouch*)[touches anyObject] locationInView:self];
for (UIView *aSubview in _roundButtons) {
if ([aSubview isKindOfClass:[UIButton class]]) {
UIButton *aButton = (UIButton*)aSubview;
CGPoint buttonTouchPointConverted = [aButton convertPoint:touchLocation toView:aButton];
if (CGRectContainsPoint([[aButton layer] frame], buttonTouchPointConverted)) {
[aButton sendActionsForControlEvents:UIControlEventTouchUpInside];
return;
}
}
}
}
The only change I have made is to have the button send that control event for us.
Original Answer
In the function that handles your gesture, do this,
if ( gesture.state == UIGestureRecognizerStateEnded ) {
CGPoint point = [gesture locationInView:button];
if ( CGRectContainsPoint(button.bounds, point) ) {
[button sendActionsForControlEvents:UIControlEventTouchUpInside];
}
}
This checks whether the last touch of the gesture was inside the button and sends a touch up inside event to all its targets.
Ok guys finally I solved my problem and I reached my goal!!
I discovered what was the real problem.
Simply the GestureRecognizer handle touch Event until it's state is setted to UIGestureRecognizerStateEnded and for this reason the GestureRecognizer swallow touch events with no opportunity to send touch events to the rest of responder chain.
I read again the UIGestureRecognizer class reference and I found the property enabled.
To solve my problem the first thing I do when the gesture launch the target method is to set the gesture enabled to NO. In this way the gesture release immediately the touch control and the touchMoved can be executed.
Hope this help someone.
Above the modified code:
-(void)showMenu:(UIGestureRecognizer*)gesture {
[gesture setEnabled:NO]; // This is the key line of my problem!!
[profileImageView removeGestureRecognizer:gesture];
[profileImageView setUserInteractionEnabled:NO];
ConcentricRadius radius;
radius.externalRadius = 75;
radius.internalRadius = 45;
GTCircularButton *circularMenu = [[[GTCircularButton alloc] initWithImage:[UIImage imageNamed:#"radio.png"] highlightedImage:[UIImage imageNamed:#"radio_selected.png"] radius:radius] autorelease];
[circularMenu setTag:kCircularTagControllerCircularMenu];
[circularMenu setCenter:[profileImageView center]];
// Buttons' frames will be set up by the circularMenu
UIButton *button1 = [[[UIButton alloc] init] autorelease];
UIButton *button2 = [[[UIButton alloc] init] autorelease];
UIButton *button3 = [[[UIButton alloc] init] autorelease];
UIButton *button4 = [[[UIButton alloc] init] autorelease];
[circularMenu setButtons:[NSArray arrayWithObjects:button1, button2, button3, button4, nil]];
//[[self view] addSubview:circularMenu];
[[self view] insertSubview:circularMenu belowSubview:profileImageView];
}
I think you should change a setting on the view, once you create the button. Eg.
myImageView.userInteractionEnabled = NO;
This way, the UIImageView will not listen to the touches any more.
Let me know if it works.