Is it possible to register a touch of a picture without using UIButton? And if it is, how can i do this?
I can just think of changing the background of a button in the code, and then use IBAction to detect the touch.
Btw, sorry for my english.
Sure. You can put a UITapGestureRecognizer on a UIImageView (remember to set the image view's userInteractionEnabled property to YES):
// assumes "myImageView" is your UIImageView that has user interaction enabled
UITapGestureRecognizer * tap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tap:)] autorelease];
[myImageView addGestureRecognizer:tap];
later in your controller...
- (void)tap:(UITapGestureRecognizer *)recognizer
{
// whatever you want
}
However, you can set up a UIButton to basically be a dumb image. Just set the background image for the normal state, disable all the adjusting on highlighting and touches, and you should have exactly what you're thinking of.
If I've misunderstood what you're getting at, feel free to clarify.
Related
I was wondering how you would hide an image in Objective-C.
I know you can hide text or a button like this
StartGame.hidden = YES;
But when I try to do this with an image, i get an error.
Since UILabel, UIButton, UIControl and UIImageView are all childs from UIView they all have the hidden property to hide them.
So any instance of the of a view (or its childs) can be hidden by setting the hidden property to YES.
If your UIImageView is part of your viewcontroller it would make sense to make a property of it rather then just an variable, but I can not see your full code or error to say that the error might be found there.
Also property or variables should not start with a capital, its not in line with the Objective-C style.
UIImageView *ImageView=[[UIImageView alloc] initWithFrame:CGRectMake(x, y,width, height)];
[ImageView setImage:[UIImage imageNamed:#"image.png"]];
and to hide this image You just need to write
[ImageView setHidden:YES];
I've put a UIButton inside a custom UIView and the button is not receiving any touch events (it doesn't get into the highlighted state, so my problem is not about being unable to wire up a touch inside up handler). I've tried both putting it into the XIB in Interface Builder, and also tried programatically adding the UIButton into the UIView seperately, both ended with no luck. All my views are inside a UIScrollView, so I first though UIScrollView may be blocking them, so I've also added a button programatically exactly the same way I add my custom view into UIScrollView, and the button worked, elimination the possibility of UIScrollView could be the cause. My View's hiearchy is like this:
The button is over the image view, and the front layer isn't occupying my button completely, so there's no reason for me not be physically interacting with the button. At my custom view's code side, I'm creating my view as such:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
UIView *sub = [[[NSBundle mainBundle] loadNibNamed:#"ProfileView" owner:self options:nil] objectAtIndex:0];
[self addSubview:sub];
[sub setUserInteractionEnabled:YES];
[self setUserInteractionEnabled:YES];
CALayer *layer = sub.layer;
layer.masksToBounds = YES;
layer.borderWidth = 5.0;
layer.borderColor = [UIColor whiteColor].CGColor;
layer.cornerRadius = 30.0;
/*layer.shadowOffset = CGSizeZero;
layer.shadowRadius = 20.0;
layer.shadowColor = [[UIColor blackColor] CGColor];
layer.shadowOpacity = 0.8;
*/
}
return self;
}
I've tried all combinations of setUserInteractionsEnabled, and had no luck. (Yes, also set them to checked in Interface Builder too). I've also read in another question with a similar problem that I should try overriding 'canBecomeFirstResponder' to return 'YES' and I've also done that too. But the problem persists, I can't click the button. I've not given any special properties, settings to the button, it's just a regular one. My other objects in the view (labels below, image view behind the button etc.) are working properly without problems. What could be possibly wrong here?
Thanks,
Can.
UPDATE: Here is a quick reproduction of the problem: https://dl.dropbox.com/u/79632924/Test.zip
Try to run and click the button.
Looking at the test project, I believe your problem in the way you create TestView, you do not specify the frame for it, so basically the parent view is 0 size, and the subviews you see from XIB extending out of the parent view and thus do not get anything in responder chain.
You should either specify the frame when creating TestView, or adjust the frame after loading XIB file.
I have had this problem as well. The cause for me was that the UIButton superview frame was of height 0, so I believe that even though a touch was happening, it was not being passed down to the button.
After making sure that the button's superview took a larger rectangle as a frame the button actions worked.
The root cause for this problem on my side was a faulty auto layout implementation (I forgot to set the height constraint for the button's superview).
I've found the solution. I was initializing my custom view as:
MyView *view = [[MyView alloc] init];
I've initialized it instead with a frame of my view's size, and it started responding to events:
CGRect rect = CGRectMake(0,0,width,height);
MyView *view = [[MyView alloc] initWithFrame:rect];
Storyboard Solution
Just for anyone wanting a solution to this when using storyboards and constraints.
Add a constraint between the superview (containing the button) and the UIButton with an equal heights constraint.
In my case, I had selected embed UIButton in a UIView with no inset on the storyboard. Adding the additional height constraint between the UIButton and the superview allowed the UIButton to respond to touches.
You can confirm the issue by starting the View Debugger and visually confirm that the superview of the UIButton is not selectable.
(Xcode 11, *- Should also work in earlier versions)
I have an UIImageViews with userInteractionEnabled, and i want to know with image i currently tap. What i should do to know that? I have a poster wall and class for that ThumbPosterModel there i have all poster information with i want to pass through.
So my code is:
for (ThumbPosterModel *tPoster in _thumbsPosterStack) {
UIImageView *imageView = [[UIImageView alloc] initWithImage:tPoster.thumb];
imageView.userInteractionEnabled = YES;
imageView.frame = CGRectMake(i, imageView.frame.origin.y, imageView.frame.size.width, imageView.frame.size.height);
[_posterWallScrollView addSubview:imageView];
UITapGestureRecognizer *tap =
[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(imageTapped:)];
[imageView addGestureRecognizer:tap];
}
And then i have:
-(IBAction)imageTapped:(id)sender {
//something do here, but know i don't know what.
}
Should i subclass UIImageView that should contains all ThumbPosterModel params? I don't think it is good idea, but i can't figure any other solution.
Ok this is very simple just add tag proprty of each image with appropriate and distinct value other then 0 and use that proprty to identify the image :)
Happy Coding :)
When the gesture recognizer is fired the sender in the action is the recognizer, so you can get the UIView it is attached to by calling [sender view];
So you could write a method which searched the thumbs poster stack and found the poster with the matching thumb, but it would probably be easier to create a UIImageView subclass which contains a reference to the poster. So when you get the view just do
PosterImageView *selectedPosterView = (PosterImageView *) [sender view];
ThumbPosterModel *selectedModel = selectedPosterView.model;
Set a tag to your each imageView.
Each for loop iteration add your image view to a NSMutableArray (arrayRef).
Accessing the tag of image view when you tap the image view(tagImage) .
then
UIIMageView *imageViewR=[arrayRef objectAtIndex:tagImage-1];
The imageViewR is the tap imageView
I have an "PDF Viewer" in my application. I use the CGPDFDocumentRef and CGPDFPageRef to show the PDF. To zoom in the PDF I use a UIScrollView.
I am already able to pinch-zoom in the UIScrollView but I also want to be able to double-tap to zoom.
Double tap with one finger takes you to different levels in the PDF until you hit the maximumZoomLevel and then be able to double-tap with two fingers to the minimumZoomLevel.
I haven't been able to find a solution on the Internet that shows you this in particular so I'm asking here. How could I accomplish this?
In viewDidLoad:
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleDoubleTap:)];
[doubleTap setNumberOfTapsRequired:2];
[self.scrollView addGestureRecognizer:doubleTap];
[doubleTap release];
Method:
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer
{
if(self.scrollView.zoomScale > self.scrollView.minimumZoomScale)
[self.scrollView setZoomScale:self.scrollView.minimumZoomScale animated:YES];
else
[self.scrollView setZoomScale:self.scrollView.maximumZoomScale animated:YES];
}
I think that you can use UITapGestureRecognizer with numberOfTapsRequired property after that in handle method (which you specify when alloc/init the recognizer) and use to use – zoomToRect:animated: or – setZoomScale:animated: on the view to zoom.
Edit: keep track on current zoom level to reverse the effect.
I have a gesture recogniser to detect a tap on a UIImageView, however I force a position change of the image when the orientation of the iPad changes but this causes the gesture recogniser to repositioned incorrectly. How can I resolve this?
EDIT:
strapTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(strapTap:)];
[(UITapGestureRecognizer *)strapTap setNumberOfTapsRequired:1];
strapTap.delegate = self;
[leatherButtonedStrap addGestureRecognizer:strapTap];
This above is how I setup the gesture, adding it to my UIImageView. However, something which might cause a stir is that I add the this view to my main view, remove it and then re-add it when the user presses a certain button. Hard for you to understand whats happening unless you saw the entire class, but let me know if this is enough to go on or not.
Make sure when you're calling locationInView: in strapTap: to send the leatherButtonedStrap as the parater:
CGPoint location = [recognizer locationInView:leatherButtonedStrap];
So that the location is relative to leatherButtonedStrap's coordinate system an not it's superview's.