Right now, I have two different UILabels each with their own long press and pan UIGestureRecognizers (setup through the storyboard). My final goal is to have each UILabel change color when long pressed, and without lifting their finger to end the long press, to change the value of the UILabel itself when the user pans up and down or side to side.
Right now, each UILabel has its own pan gesture method and long press gesture method. Is there any way to have a single long press/pan method for both UILabels but also have the ability to do something for one label and something else for another?
Also, is there a better approach to doing this? Eventually, I would also like to implement visual feedback when changing the value of the labels, such as in the form of animations.
I am new to iOS programming and programming in general and detailed answers are greatly appreciated. Thanks.
You can have a single function.No need to have seperate gestures for seperate Label.Example
//First add tag value to ur labels
label_one.tag=1;
label_two.tag=2;
UIPanGestureRecognizer * _panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self
action:#selector(handlePanGesture:)];
_panGestureRecognizer.delegate = self;
[label_one addGestureRecognizer:_panGestureRecognizer];
UIPanGestureRecognizer * _panGestureRecognizer_two = [[UIPanGestureRecognizer alloc] initWithTarget:self
action:#selector(handlePanGesture:)];
_panGestureRecognizer_two.delegate = self;
[label_two addGestureRecognizer:_panGestureRecognizer_two];
-(void)handlePanGesture:(UIPanGestureRecognizer*)sender{
if(sender.tag==1){
}
else if(sender.tag==2){
}
}
Same goes for other gesture as well
I have a UITableView with a bunch of cells, and I add a UILabel to each. I want the UILabel, when tapped, to accept the touches, not the cell. Obviously if they tap outside of the label and still on the cell that is fine, but if it's on the label the cell should not cause a segue or action or whatever, only the label's action on tap should fire.
My normal method to cause this is to set the UIView's userInteractionEnabled to YES, but in this case when I set it on the label it doesn't cause anything different to happen. When I watch touchesBegan in the label subclass those methods do fire, but the cell selection does as well.
How do I make the UILabel not pass the touches on to the cell?
I recommend adding a UITapGestureRecognizer to the label and setting cancelsTouchesInView property to YES to prevent the touches from being delivered to the view upon gesture recognition, ex:
UITapGestureRecognizer *labelTapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:nil];
labelTapGesture.cancelsTouchesInView = YES;
[label addGestureRecognizer:labelTapGesture];
label.userInteractionEnabled = YES;
And since you don't want the gesture to perform an action, you can set its action to nil.
It may seem like duplicate, but I can't actually find any good answer to my concrete situation.
I have some button with background image (1pt-wide, streched), icon-like image inside along with the text label. It's height is 33pt, I need to make it's hittest area 44pt-high.
I saw two solutions, but neither of them works for me.
First solution is to enlarge frame and adjust image so it would have some padding. But that is not acceptable for me, because I have both background image and image inside the button.
Second solution is to subclass UIButton (which is absolutely acceptable) and override - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event. I did that, when I put some breakpoints in this method and tried to tap in desired area nothing happened (breakpoints worked when tapped inside the button frame).
Are there any other solutions? What could be possibly wrong with the second solution?
If you create the view programmatically, you can instantiate a UIView that is 44px high, add a tap gesture recognizer to it, and add your UIButton as a subview inside this view:
CGRect bigFrame = CGRectMake(0,0,100,44);
UIView *big = [[UIView alloc] initWithFrame:bigFrame];
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(doPress)];
[big addGestureRecognizer:tapRecognizer];
UIButton *yourButton = ...
[big addSubview:yourButton];
[self.view addSubview:big];
Then implement the selector as:
- (void)doPress {
[yourButton sendActionsForControlEvents:UIControlEventTouchUpInside];
}
In that way, the outer view taps will be interpreted as button presses for your button.
First off this question has been helpful in my understanding of how to subclass UIButton for long presses. I would like to do the same for UISegmentedControl, however I don't see how I would be able to identify which segment was held down since UISegmentedControl does allow direct access to it's segments (UISegmentedControl.h shows them as private). I could just customize a few UIButtons to look like an UISegmentedControl however I would also have to implement the momentary switch logic. Which wouldn't be a big deal but subclassing UISegmentedControl seems cleaner to me.
BTW, I'm using this control to imitate a radio's preset controls: tap to go to a saved station and hold to assign the current station to that segment.
I tried this without subclassing and it seems to work.
UILongPressGestureRecognizer* recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(pressGesture:)];
recognizer.delegate = self;
[mySegCtrl addGestureRecognizer:recognizer];
[recognizer release];
...
-(void)pressGesture:(UILongPressGestureRecognizer*)gesture
{
NSLog(#"pressGesture %#", gesture);
}
Long press first selects the segment then fires the gesture. If you aren't getting the callback check my code - I got stuck for a while because I wasn't setting recognizer.delegate=self.
I have placed an image (UIImageView) on the navigation bar. Now I want to detect the touch event and want to handle the event. How can I do that?
In practical terms, don't do that.
Instead add a button with Custom style (no button graphics unless you specify images) over the UIImageView. Then attach whatever methods you want called to that.
You can use that technique for many cases where you really want some area of the screen to act as a button instead of messing with the Touch stuff.
A UIImageView is derived from a UIView which is derived from UIResponder so it's ready to handle touch events. You'll want to provide the touchesBegan, touchesMoved, and touchesEnded methods and they'll get called if the user taps the image. If all you want is a tap event, it's easier to just use a custom button with the image set as the button image. But if you want finer-grain control over taps, moves, etc. this is the way to go.
You'll also want to look at a few more things:
Override canBecomeFirstResponder and return YES to indicate that the view can become the focus of touch events (the default is NO).
Set the userInteractionEnabled property to YES. The default for UIViews is YES, but for UIImageViews is NO so you have to explicitly turn it on.
If you want to respond to multi-touch events (i.e. pinch, zoom, etc) you'll want to set multipleTouchEnabled to YES.
To add a touch event to a UIImageView, use the following in your .m file:
UITapGestureRecognizer *newTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(myTapMethod)];
[myImageView setUserInteractionEnabled:YES];
[myImageView addGestureRecognizer:newTap];
-(void)myTapMethod{
// Treat image tap
}
You can also add a UIGestureRecognizer. It does not require you to add an additional element in your view hierarchy, but still provides you will all the nicely written code for handling touch events with a fairly simple interface:
UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc]
initWithTarget:self action:#selector(handleSwipe:)];
swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
[imgView_ addGestureRecognizer:swipeRight];
[swipeRight release];
UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc]
initWithTarget:self action:#selector(handleSwipe:)];
swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
[imgView_ addGestureRecognizer:swipeLeft];
[swipeLeft release];
I've been on different threads on the past few hours trying to find a solution for my problem, to no avail. I see that many developers share this problem, and I think people here know about this. I have multiple images inside a UIScrollView, trying to get tap events on them.
I am not getting any events from an UIImangeView, but I do get an event from a similar UILable with very similar parameters I am setting to it. Under iOS 5.1.
I have already done the following:
set setUserInteractionEnabled to YES for both `UIImageView and parent
view .
set setMultipleTouchEnabled to YES for UIImageView.
Tried subclassing UIImageView, didn't help any.
Attaching some code below, in this code I initialize both a UIImageView and UILabel, the label works fine in terms of firing events. I tried keeping out irrelevant code.
UIImageView *single_view = [[UIImageView alloc]initWithFrame:CGRectMake(200, 200, 100, 100)];
single_view.image = img;
single_view.layer.zPosition = 4;
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTapGestureCaptured:)];
[single_view addGestureRecognizer:singleTap];
[single_view setMultipleTouchEnabled:YES];
[single_view setUserInteractionEnabled:YES];
[self.myScrollView addSubview:single_view];
self.myScrollView.userInteractionEnabled = YES;
UILabel *testLabel = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];
testLabel.backgroundColor = [UIColor redColor];
[self.myScrollView addSubview:testLabel];
[testLabel addGestureRecognizer:singleTap];
[testLabel setMultipleTouchEnabled:YES];
[testLabel setUserInteractionEnabled:YES];
testLabel.layer.zPosition = 4;
And the method which handles the event:
- (void)singleTapGestureCaptured:(UITapGestureRecognizer *)gesture
{
UIView *tappedView = [gesture.view hitTest:[gesture locationInView:gesture.view] withEvent:nil];
NSLog(#"Touch event on view: %#", [tappedView class]);
}
As said, the label tap is received.
Instead of making a touchable UIImageView then placing it on the navbar, you should just create a UIBarButtonItem, which you make out of a UIImageView.
First make the image view:
UIImageView *yourImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"nameOfYourImage.png"]];
Then make the barbutton item out of your image view:
UIBarButtonItem *yourBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:yourImageView];
Then add the bar button item to your navigation bar:
self.navigationItem.rightBarButtonItem = yourBarButtonItem;
Remember that this code goes into the view controller which is inside a navigation controller viewcontroller array. So basically, this "touchable image-looking bar button item" will only appear in the navigation bar when this view controller when it's being shown. When you push another view controller, this navigation bar button item will disappear.
You might want to override the touchesBegan:withEvent: method of the UIView (or subclass) that contains your UIImageView subview.
Within this method, test if any of the UITouch touches fall inside the bounds of the UIImageView instance (let's say it is called imageView).
That is, does the CGPoint element [touch locationInView] intersect with with the CGRect element [imageView bounds]? Look into the function CGRectContainsPoint to run this test.
First, you should place an UIButton and then either you can add a background image for this button, or you need to place an UIImageView over the button.
Or:
You can add the tap gesture to a UIImageView so that get the click action when tap on the UIImageView.
For those of you looking for a Swift 4 solution to this answer, you can use the following to detect a touch event on a UIImageView.
let gestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(imageViewTapped))
imageView.addGestureRecognizer(gestureRecognizer)
imageView.isUserInteractionEnabled = true
You will then need to define your selector as follows:
#objc func imageViewTapped() {
// Image has been tapped
}
Add gesture on that view. Add an image into that view, and then it would be detecting a gesture on the image too. You could try with the delegate method of the touch event. Then in that case it also might be detecting.