If I have a UIImageView and want to know if a user has tapped the image. In touchesBegan, I do the following but always end up in the first conditional. The window is in portrait mode and the image is at the bottom. I can tap in the upper right of the window and still go into the first condition, which seems very incorrect.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:touch.view];
if(CGRectContainsPoint(myimage.frame, location) == 0){
//always end up here
}
else
{ //user didn't tap inside image}
and the values are:
location: x=303,y=102
frame: origin=(x=210,y=394) size=(width=90, height=15)
Any suggestions?
First, you get the touch with:
UITouch *touch = [[event allTouches] anyObject];
Next, you want to be checking for the locationInView relative to your image view.
CGPoint location = [touch locationInView:self]; // or possibly myimage instead of self.
Next, CGRectContainsPoint returns a boolean, so comparing it to 0 is very odd. It should be:
if ( CGRectContainsPoint( myimage.frame, location ) ) {
// inside
} else {
// outside
}
But if self is not myimage then the myimage view may be getting the touch instead of you - its not clear from your question what object self is it is is not a subclass of the UIImageView in question.
Your logic is simply inverted. The CGRectContainsPoint() method returns bool, i.e. true for "yes". True is not equal to 0.
Related
I've implemented drag and drop for multiple images which works fine but I'm facing one issue. When I'm dragging one image, other images will be nudged along when my finger moves over them whilst Im still dragging the original image. I'd love to be able to have only one image moveable at once.
Heres some of my code.
-(void)touchesBegan: (NSSet *) touches withEvent:(UIEvent *)event{
UITouch* touch = [touches anyObject];
for (UIImageView *noseImage in noseArray) {
if ([touch.view isEqual:noseArray]) {
firstTouchPoint = [touch locationInView:[self view]];
xd = firstTouchPoint.x - [[touch view]center].x;
yd = firstTouchPoint.y - [[touch view]center].y;
}
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject];
CGPoint oldPoint = [touch previousLocationInView:touch.view];
CGPoint newPoint = [touch locationInView:touch.view];
CGPoint diff = CGPointMake(newPoint.x - oldPoint.x, newPoint.y - oldPoint.y);
for (UIImageView *noseImageView in noseArray) {
if (CGRectContainsPoint(noseImageView.frame, newPoint)) {
CGPoint cntr = [noseImageView center];
[noseImageView setCenter:CGPointMake(cntr.x + diff.x, cntr.y + diff.y)];
}
}
}
Typically you would determine which image is being dragged in the touchesBegan: and remember that. Then in the touchesMoved:, move the remembered image the given amount.
But a Gesture Recogniser works a lot easier than these low level methods, so I suggest you use that instead.
You wrote:
for (UIImageView *noseImage in noseArray) {
if ([touch.view isEqual:noseArray]) {
Are you sure the second line shouldn't be the following?
if ([touch.view isEqual: noseImage]) {
I have added an image on the SKScene using the following code -
char1 = [[SKSpriteNode alloc] initWithImageNamed:#"CH_designb_nerd.png"];
char1.position = CGPointMake(225.0, 65.0);
char1.anchorPoint = CGPointMake(0, 0);
[char1 setScale:0.35];
[self addChild:char1];
Then I was trying to create a touch event on the image but CGRect of the image seems totally flipped on the other side of the screen. I have used the following code
(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:self.view];
if (CGRectContainsPoint(char1.frame, location)) {
NSLog(#"yaaa!!");
}
else{
NSLog(#"%.2f",location.x);
NSLog(#"%.2f",char1.position.x);
}
}
Im totally lost on this as the image is placed perfectly but the coordinates or the CGRect seems flipped. The image is placed on the bottom but only when i touch on top of the screen does it say touch occurred.
I imagine this is due to getting the wrong click location. I would instead look at using the SKNode equivalent for hit testing. Something like this:
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInNode:self];
SKSpriteNode *char1 = (SKSpriteNode *)[self childNodeWithName:#"char1Name"];
if ([char1 containsPoint:location])
{
...
}
There might be some syntax errors here, typing from memory but you get the gist. Note: you would need to set the name property for char1 to perform the lookup, or you could just enumerate self.children if there is only that node.
Try this.
UITouch * touch = [touches anyObject];
CGPoint location = [touch locationInNode:self];
Nice example of spriteKit Link
I've got two UIViews on my window: one to hold player scores, (a sidebar), and a main play area. They both fit on the UIWindow, and neither scroll. The user can drag UIButtons around on the main play area – but at present, they can drop them onto the sidebar. Once they do, they can't drag them again to bring them back, presumably because you're then tapping on the second view, which doesn't contain the button in question.
I'd like to prevent anything inside the main view being moved onto the sidebar view. I've managed this, but I need the drag to be released if the player's finger moves off that view. With the code below, the button keeps moving with the finger, but just won't go past the X coordinate of the view. How can I go about this? Dragging is enabled using this call:
[firstButton addTarget: self action: #selector(wasDragged: withEvent:) forControlEvents: UIControlEventTouchDragInside];
To this method:
- (void) wasDragged: (UIButton *) button withEvent: (UIEvent *) event
{
if (button == firstButton) {
UITouch *touch = [[event touchesForView:button] anyObject];
CGPoint previousLocation = [touch previousLocationInView:button];
CGPoint location = [touch locationInView:button];
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
if ((button.center.x + delta_x) < 352)
{
button.center = CGPointMake(button.center.x + delta_x, button.center.y + delta_y);
} else {
button.center = CGPointMake(345, button.center.y + delta_y);
}
}
}
implement
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
touch delegate method, then check the location of the UITouch, if the location is outside of the bounds you want to allow (the first view), then don't move it any further. You could also kill the touch at the point the user drags outside the view using a BOOL iVar
//In .h file
BOOL touchedOutside;
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
touchedOutside = NO;
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if (!touchedOutside) {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:firstView];
if (location.x < UPPER_XLIMIT && location.x > LOWER_XLIMIT) {
if (location.y < UPPER_YLIMIT && location.x > LOWER_YLIMIT) {
//Moved within acceptable bounds
button.centre = location;
}
} else {
//This will end the touch sequence
touchedOutside = YES;
//This is optional really, but you can implement
//touchesCancelled: to handle the end of the touch
//sequence, and execute the code immediately rather than
//waiting for the user to remove the finger from the screen
[self touchesCancelled:touches withEvent:event];
}
}
I need get touch location, and I created an method to get it.. but when I touch in my ScrollView, the method dont return the location, only out of scrollView.
this is the code:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint pos = [touch locationInView:nil];
NSLog(#"Position of touch: %.0f, %.0f", pos.x, pos.y);
}
someone knows how to do it?
thanks!
CGPoint pos = [touch locationInView:nil];
You are retrieving the coordinates of the touch with respect to the window's origin. Per the documentation:
view
The view object in whose coordinate system you want the touch
located. A custom view that is handling the touch may specify self to
get the touch location in its own coordinate system. Pass nil to get
the touch location in the window’s coordinates.
To get the coordinates in your scroll view, you need to pass self:
CGPoint pos = [touch locationInView:self];
I am developing a simple animation where an UIImageView moves along a UIBezierPath, now I want to provide user interation to the moving UIImageView so that user can guide the UIImageView by touching the UIImageView and drag the UIImageview around the screen.
Change the frame of the position of the image view in touchesMoved:withEvent:.
Edit: Some code
- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
UITouch *touch = [[event allTouches] anyObject];
if ([touch.view isEqual: self.view] || touch.view == nil) {
return;
}
lastLocation = [touch locationInView: self.view];
}
- (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
UITouch *touch = [[event allTouches] anyObject];
if ([touch.view isEqual: self.view]) {
return;
}
CGPoint location = [touch locationInView: self.view];
CGFloat xDisplacement = location.x - lastLocation.x;
CGFloat yDisplacement = location.y - lastLocation.y;
CGRect frame = touch.view.frame;
frame.origin.x += xDisplacement;
frame.origin.y += yDisplacement;
touch.view.frame = frame;
lastLocation=location;
}
You should also implement touchesEnded:withEvent: and touchesCanceled:withEvent:.
So you want the user to be able to touch an image in the middle of a keyframe animation along a curved path, and drag it to a different location? What do you want to happen to the animation at that point?
You have multiple challenges.
First is detecting the touch on the object while a keyframe animation is "in flight".
To do that, you want to use the parent view's layer's presentation layer's hitTest method.
A layer's presentation layer represents the state of the layer at any given instant, including animations.
Once you detect touches on your view, you will need to get the image's current location from the presentation layer, stop the animation, and take over with a touchesMoved/touchesDragged based animation.
I wrote a demo application that shows how to detect touches on an object that's being animated along a path. That would be a good starting point.
Take a look here:
Core Animation demo including detecting touches on a view while an animation is "in flight".
Easiest way would be subclassing UIImageView.
For simple dragging take a look at the code here (code borrowed from user MHC):
UIView drag (image and text)
Since you want to drag along Bezier path you'll have to modify touchesMoved:
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *aTouch = [touches anyObject];
//here you have location of user's finger
CGPoint location = [aTouch locationInView:self.superview];
[UIView beginAnimations:#"Dragging A DraggableView" context:nil];
//commented code would simply move the view to that point
//self.frame = CGRectMake(location.x-offset.x,location.y-offset.y,self.frame.size.width, self.frame.size.height);
//you need some kind of a function
CGPoint calculatedPosition = [self calculatePositonForPoint: location];
self.frame = CGRectMake(calculatedPosition.x,calculatedPosition.y,self.frame.size.width, self.frame.size.height);
[UIView commitAnimations];
}
What exactly you would like to do in -(CGPoint) calculatePositionForPoint:(CGPoint)location
is up to you. You could for example calculate point in Bezier path that is the closest to location. For simple test you can do:
-(CGPoint) calculatePositionForPoint:(CGPoint)location {
return location;
}
Along the way you're gonna have to decide what happens if user wonders off to far from your
precalculated Bezier path.