in my application I'm using touchesMoved method to detect swipe left/right.
when the user swipe to left and right continuously,image animation updates automatically.
I was able to detect swipe action but sometimes when I start to swipe left and right continuously,screen doesn't detect the touchmoved event.
in the swipe area I have placed one hidden button and few ImageViews for animations.
I want to know why it happens.please help me.
thank you.
code:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesMoved:touches withEvent:event];
UITouch *touch = [touches anyObject];
CGPoint newLocation = [touch locationInView:self.view];
CGPoint oldLocation = [touch previousLocationInView:self.view];
if(newLocation.x-oldLocation.x>0){
swipe_direction = 1;
//NSLog(#"left");
}
else{
swipe_direction = 2;
//NSLog(#"right");
}
if(swipe_direction == 1){
//animate images
}
else if(swipe_direction == 2){
//animate images
}
}
touchesMoved Only detects on the empty part of the View. Therefore, it will not detect over the objects you used.
Place a SwipeGestureRecognizer over the view and use it from there.
Have you considered using a SwipeGestureRecognizer instead of the touchesMoved?
Check the Documentation
I am trying to make a simple landscape "split screen" app where two players can play at once (each player gets one half of the screen), but I am having trouble tracking both touches at the same time. This is the code I am trying to use:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
CGPoint point = [touch locationInView:self.view];
if (point.x < 240) {
[player1 updatePoint:point];
} else {
[player2 updatePoint:point];
}
}
}
But I am obviously doing something wrong. Although this code works fine, it will only track one finger and move the player on the side of the screen the finger is on. What is my code lacking? Is this task more difficult to pull off then I think it is?
Did you set UIView's multipleTouchEnabled to YES?
multipleTouchEnabled should be set to YES for the UIView.
I spend quite some time to figure out how to achieve what I want to do but didn't find a proper solution for it, yet. I have a UIScrollView where I changed the panGestureRecognizer from one to two finger recognition so the paging only works when two fingers are used. Now I want to add an additional panGestureRecognizer that shows a courser if I'm panning with one finger. I tried that by just adding an additional panGestureRecognizer to the UIScrollView but then the app crashes immediately. So I thought of adding a subview that is transparent and positioned above the UIScrollView and that I delegate the two finger gestures to the UIScrollView with something like resgin firstResponder. I also thought of overwriting the pangestureRecognizer of the UIScrollView and let it add a Subview where my "fingerpointer"(a little point that is centered where I'm touching the screen right now) is located. I'm totally clueless what way I should go and how to implement it. Your help is greatly appreciated! Thanks a lot!
Timo
Ok, this is the second time editing my response. This might do the trick for you.
If you extend UIScrollView you can override these methods in this way:
//In your h file
BOOL cursorShown;
//In your m file
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if([touches count] == 1)
{
cursorShown = YES;
CGPoint touchLocation = [[touches anyObject] locationInView:self.superview]
//Add your cursor to the parent view here and set its location to touchLocation
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
if(cursorShown == YES)
{
CGPoint touchLocation = [[touches anyObject] locationInView:self.superview]
//Move your cursors location to touchLocation
}
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
if(cursorShown == YES)
{
cursorShown = NO;
//Destroy your cursor
}
}
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
if(cursorShown == YES)
{
cursorShown = NO;
//Destroy your cursor
}
}
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()
Please can someone help sort a noob out? I've posted this problem on various forums and received no answers, while many searches for other answers have turned up stackOverflow, so I'm hoping this is the place.
I've got a BeachView.h (subclass of UIScrollView, picture of a sandy beach) covered with a random number of Stone.h (subclass of UIImageView, a random PNG of a stone, userInteractionEnabled = YES to accept touches).
If the user touches and moves on the beach, it should scroll.
If the user taps a stone, it should call method "touchedStone".
If the user taps the beach where there is no stone, it should call method "touchedBeach".
Now, I realize this sounds dead simple. Everyone and everything tells me that if there's something on a UIScrollView that accepts touches that it should pass control on to it. So when I touch and drag, it should scroll; but if I tap, and it's on a stone, it should ignore beach taps and accept stone taps, yes?
However, it seems that both views are accepting the tap and calling both touchedStone AND touchedBeach. Furthermore, the beach tap occurs first, so I can't even put in a "if touchedStone then don't run touchedBeach" type flag.
Here's some code.
On BeachView.m
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.decelerating) { didScroll = YES; }
else { didScroll = NO; }
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:touch.view];
NSLog(#"touched beach = %#", [touch view]);
lastTouch = touchLocation;
[super touchesBegan:touches withEvent:event];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
didScroll = YES;
[super touchesMoved:touches withEvent:event];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (didScroll == NO && isPaused == NO) {
[self touchedBeach:YES location:lastTouch];
}
[super touchesEnded:touches withEvent:event];
}
On Stone.m
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[parent stoneWasTouched]; // parent = ivar pointing from stone to beachview
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:touch.view];
NSLog(#"touched stone = %#", [touch view]);
[parent touchedStone:YES location:touchLocation];
}
After a stone tap, My NSLog looks like this:
Touched beach = <BeachView: 0x1276a0>
ran touchedBeach
Touched Stone = <Stone: 0x1480c0>
ran touchedStone
So it's actually running both. What's even stranger is if I take the touchesBegan and touchesEnded out of Stone.m but leave userInteractionEnabled = YES, the beachView registers both touches itself, but returns the Stone as the view it touched (the second time).
Touched beach = <BeachView: 0x1276a0>
ran touchedBeach
Touched beach = <Stone: 0x1480c0>
ran touchedBeach
So PLEASE, I've been trying to sort this for days. How do I make it so a tapped stone calls only touchedStone and a tapped beach calls only touchedBeach? Where am I going wrong?
Is true, iPhone SDK 3.0 and up, don't pass touches to -touchesBegan: and -touchesEnded: **UIScrollview**subclass methods anymore. You can use the touchesShouldBegin and touchesShouldCancelInContentView methods that is not the same.
If you really want to get this touches, have one hack that allow this.
In your subclass of UIScrollView override the hitTest method like this:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
UIView *result = nil;
for (UIView *child in self.subviews)
if ([child pointInside:point withEvent:event])
if ((result = [child hitTest:point withEvent:event]) != nil)
break;
return result;
}
This will pass to you subclass this touches, however you can't cancel the touches to UIScrollView super class.
Prior to iPhone OS 3.0, the UIScrollView's hitTest:withEvent: method always returns self so that it receives the UIEvent directly, only forwarding it to the appropriate subview if and when it determines it's not related to scrolling or zooming.
I couldn't really comment on iPhone OS 3.0 as it's under NDA, but check your "iPhone SDK Release notes for iPhone OS 3.0 beta 5" :)
If you need to target pre-3.0, you could override hitTest:withEvent: in BeachView and set a flag to ignore the next beach touch if the CGPoint is actually in a stone.
But have you tried simply moving your calls to [super touches*:withEvent:] from the end of your overridden methods to the start? This might cause the stone tap to occur first.
I had a similar problem with a simpleView and it is added to a scrollView , and whenever I touched the simpleView , the scrollView used to get the touch and instead of the simpleView , the scrollView moved . To avoid this , I disabled the srcolling of the scrollView when the user touched the simpleView and otherwise the scrolling is enabled .
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
UIView *result = [super hitTest:point withEvent:event] ;
if (result == simpleView)
{
scrollView.scrollEnabled = NO ;
}
else
{
scrollView.scrollEnabled = YES ;
}
return result ;
}
This could be related to a bug in iOS7 please review my issue (bug report submitted)
UIScrollView subclass has changed behavior in iOS7