I am developing a drawing application for iOS.
I have created a list of images and when user taps on any of the images that will be selected and I also get the tag value of the selected images.
After selection I want to move the images around the screen with finger and I have successfully completed this process, but when I want to apply the tag I will not get the tag value of images with touch. My code for moving the images is below. In this View array is my on screen selected image Array.
CGPoint firstTouch = [touch locationInView:selectedPerson_ImageView];
for (UIImageView *view in viewArray) {
if (CGRectContainsPoint(view.frame, firstTouch))
{
toMove = view;
}
}
How do I get the tag value of images to be moved?
You can get the tag value of touch location view by using this
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
int viewTag=[touch view].tag;
}
Related
i need to drag an element during an animation. The element fall from the top of the screen and i need the user can drag it wherever he want, even during animation
Thanks
You can use the touchesBegan method to detect when the user touches the element.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
if (touch != nil && (touch.view == elementView))
//do your stuff
}
Then set the element's position to the touch location, and remove the animation.
elementView.center = [touch locationInView:self.view];
[elementView.layer removeAllAnimations];
This should work. Then you can use the similar touchesMoved method to update the position during the drag.
Since you're using the UIView block based animations, try using:
animateWithDuration:delay:options:animations:completion:
with the UIViewAnimationOptionAllowUserInteraction option.
Basically I am trying to make a button shaped as a circle and add an image to it. The image is a png with transparency representing a sphere. Adding it to a custom button does it, but it has one problem. The transparent content around the sphere is also clickable. How Do I make so that the nontransparent area of the image is clickable?
You can check out GKTank sample for how to register and use touches.
You have to have to register to get the touch events, then inside the event, check the location, and decide if it is hitting your graphic. To do that, you would have to know the dimmentions and shape of the round button, and then decide if the touch is inside or outside of it.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (myButtonIsActive) {
CGPoint tPoint;
UITouch *thumb = [[event allTouches] anyObject];
tPoint = [thumb locationInView:thumb.view];
// check here if tPoint is inside of the button shape/circle
I have a UIImageView and I am trying to determine when a drag is performed, how far that drag is from the origin. I currently have this:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:touch.view];
if(CGRectContainsPoint(myimage.frame, location) == 0){
}
else
{ //user didn't tap inside image}
The image itself does not move, but a person can take their finger, click on the image and then drag their finger. I am just trying to determine that drag distance.
If you want to calculate distance, you need to remember the point (store it somewhere) in touchesBegan if the user tapped on your image.
Then in touchesMoved or touchesEnd you will be able to get current point and calculate distance to your original point.
If you need to get distance from UIImageView origin, you can call [touch locationInView:myImage];
And I suggest you to use UIGestureRecognizer class instead of handling touches by yourself. They are simpler to implement.
We are adding drag and drop functionality to what is to become a sports field with positions for players.
The positions are mapped out using Interface Builder with each being a separate UIImageView.
We want to be able to drag player images from bench positions from the side of the screen onto positions on the field.
How best can we detect when the selected player which is being moved around collides with an existing gamePosition imageView?
We are looking for a way to detect if there is a view or ImageView under the current location.
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:touch.view];
tile1.center = location;
if gamePositionExistsAtCurrentLocation(location) { //want something like this
[tile1 setBackgroundColor:[UIColor blueColor]];
} else {
[tile1 setBackgroundColor:[UIColor yellowColor]];
}
}
check if the frame of the item you are moving intersects with the frame from on of your subviews
for (UIView *anotherView in self.subviews) {
if (movingView == anotherView)
continue;
if (CGRectIntersectsRect(movingView.frame, anotherView.frame)) {
// Do something
}
}
If I were you, I would add all game relevant items to an NSArray and for-loop through this. So you don't detect collisions with subviews that have nothing to do with your game like labels and so on.
Also might want to consider view.center with CGRectContainsPoint()
I have a grid of images/buttons, and I want the user to be able to drag their finger over the images/buttons such that when their finger touches each image/button an event is called.
How do I do this???
The best example I can think of now is the Contacts app, how you drag your finger down the list of letters (on the right) and as you touch each letter it jumps to that part of the contacts list.
You're going to want to implement -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event in your UIViewController. This method is called any time a touch moves on the screen. You can then either use the coordinates (use [myUITouch locationInView:self.view]) or [self.view.layer hitTest:[myUITouch locationInView:self.view]] to get the image/button the touch occurred in and work from that.
For example, if I have a row of ten images, each 32 pixels by 32 pixels, and I want to record when each of them is touched, I could do something like the following:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
CGSize buttonSize = myButton.bounds.size;
CGPoint touchPoint = [[touches anyObject] locationInView:self.view];
if (touchPoint.y < buttonSize.y) {
NSInteger buttonNumber = touchPoint.x/buttonSize.x;
NSLog(#"Button number %d pushed", buttonNumber);
}
}
Note this assumes multitouch is disabled or it will randomly pick one touch to record