I have some object on my screen view which moves by touch, but the problem is if I click somewhere else on my screen which has no object on, the last moved object skipped to that clicked position, anyone who know how I can be able to stop that? PostView contains code about my objects
in .h file
#property (weak, nonatomic) IBOutlet PostView *pv;
and .m file
- (void)viewDidLoad
{
[super viewDidLoad];
viewArray = [NSMutableArray arrayWithObjects: nil];
pv.frame = CGRectMake(10, 10, 100, 100);
pv.backgroundColor = [UIColor blackColor];
[viewArray insertObject:pv atIndex:0];
[self.view addSubview:pv];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint firstTouch = [touch locationInView:self.view];
for (PostView *view in viewArray) {
if (CGRectContainsPoint(view.frame, firstTouch)) {
toMove = view;
}
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:self.view];
toMove.center = location;
// [_delegate dragViewDidMove:self];
// toMove.center = currentTouch;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
currentTouch = [touch locationInView:self.view];
toMove.center = currentTouch;
}
Set toView to null at the start of touchesBegan:. This ensures that if the user makes a touch that touches nothing (and so toView doesn't get set to anything deliberately), nothing will happen when the touch moves (the setCenter: message will be sent to null which will return null and have no side effects.)
Related
I am trying to create a dot on the screen when it is touched and then be able to move that dot around and then ending the touch which will bring up an alert view. For the first touch and movement i have this code so far...
{
UIImageView *dot =[[UIImageView alloc] initWithFrame:CGRectMake(359,487,50,50)];
dot.image=[UIImage imageNamed:#"hockey-puck-stress-toy-superextralarge-175648.png"];
[self.view addSubview:dot];
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:touch.view];
dot.center = location;
}
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[self touchesBegan:touches withEvent:event];
}
The problem is that this creates a new object when moving instead of just when I first touch it. I understand why it does this, but i don't know any way to fix it. Could someone please help? Thanks!
Create a property in your .h file:
#property (nonatomic) UIImageView *dot;
And then just create the view if it doesn't exist and then move the property:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (!self.dot) {
UIImageView *dot =[[UIImageView alloc] initWithFrame:CGRectMake(359,487,50,50)];
dot.image=[UIImage imageNamed:#"hockey-puck-stress-toy-superextralarge-175648.png"];
[self.view addSubview:dot];
}
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:touch.view];
self.dot.center = location;
}
hey guys i was wondering if there was away to make an object like a UIImageView draggable. I am aware of the UITouch and touches i.e.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *drag=[[event allTouches] anyObject];
player.center=[drag locationInView:self.view];
}
but in this way it is possible for the user to make the object jump across the screen to where he or she touches the screen but i want the user to have to manually drag the object across the screen.
please explain with code and let me know if i have to be more specific or clear...
You can do this:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *aTouch = [touches anyObject];
CGPoint location = [aTouch locationInView:self.view];
if(CGRectContainsPoint(self.playerView.frame,location)) {
[UIView beginAnimations:#"Dragging A DraggableView" context:nil];
self.playerView.center = location;
[UIView commitAnimations];
}
}
This should give you a smooth animation.
if you want your user to drag&drop, first you have to check if the touch is inside the imageview rect frame. To improve the user experience, you can detect the touch offset from the imageview center; a good place to do this is inside the touchesBegan:withEvent:. After that, you have to change the position of the imageview, like this:
CGPoint touchOffset; //insert this inside your interface private iVars
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *drag=[[event allTouches] anyObject];
CGPoint touchLocation = [drag locationInView:self.view];
touchOffset = CGPointMake(player.center.x-touchLocation.x,player.center.y-touchLocation.y)
if(CGRectContainsPoint(player.frame,touchLocation)
player.center = CGPointMake(touchLocation.x+touchOffset.x,touchLocation.y+touchOffset.y);
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *drag=[[event allTouches] anyObject];
CGPoint touchLocation = [drag locationInView:self.view];
if(CGRectContainsPoint(player.frame,touchLocation)
player.center = CGPointMake(touchLocation.x+touchOffset.x,touchLocation.y+touchOffset.y);
}
P.S. - Next time try to search similar questions...
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch* aTouch = [touches anyObject];
UIView* aView = [aTouch view];
if (aView != self.view) {
[self.view bringSubviewToFront:aView];
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch* aTouch = [touches anyObject];
UIView* aView = [aTouch view];
if (aView != self.view) {
aView.center = [aTouch locationInView:self.view];
}
}
I'm trying to create a simple application where you can move your UIImageView by touching him and dragging him around.
my UIImageView is called imv
-(void ) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch * touch = [touches anyObject];
if([touch view] == self.imv){
CGPoint location = [touch locationInView:self.view];
self.imv.center = location;
}
}
-(void ) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch * touch = [touches anyObject];
if([touch view] == self.imv){
CGPoint location = [touch locationInView:self.view];
self.imv.center = location;
}
}
i'am trying to solve this like whole day and i don't know what is wrong. If i disable if statement it's working else not. What can i do?
Thanks for the answers
Unless you've subclassed UIImageView (unlikely), your view is receiving the touch events.
These days it's simpler & more usual to use a UIGestureRecognizer for this kind of thing, in this case a UIPanGestureRecognizer.
e.g.
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(dragImageView:)];
[self.imv addGestureRecognizer:pan];
- (void)dragImageView:(UIPanGestureRecognizer *)dragImageView {
if(UIGestureRecognizerStateBegan == state) {
originalCenter = self.imv.center; // add CGPoint originalCenter; member
} else if(UIGestureRecognizerStateChanged == state) {
CGPoint translate = [pan translationInView:self.imv.superview];
self.imv.center = CGPointMake(originalCenter.x + translate.x, originalCenter.y + translate.y);
}
}
From a bit of experimenting, it seems that the [touch view] is returning the main UIView and not your subview, hence the problem with the if statement not working (I added the UIImageView in a storyboard xib). EDIT- it's because UIImageViews don't handle touch events by default - see here . When adding a regular UIView in the viewDidLoad seems to work as you would expect.
Anyway, this adapted version of your code works for me
-(void)moveImageForTouches:(NSSet*)touches
{
UITouch * touch = [touches anyObject];
CGPoint location = [touch locationInView:self.view];
if(CGRectContainsPoint(self.imv.frame, location))
{
self.imv.center = location;
}
}
-(void ) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[self moveImageForTouches:touches];
}
-(void ) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[self moveImageForTouches:touches];
}
I have two UIImageView in the same view,I would like to move them but separately.When I move the first one,the second one should stay fix and conversely.
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:[self view]];
[imageView1 setCenter:location];
[imageView2 setCenter:location];
}
this method is a method from UIResponder class will and will be called when the UIView (UIImageView is a subclass so no problem) is moved.
What you have to do, is subclass UIImageView and don't implement this method in your superview.
MovableImageView.h
#interface MovableImageView : UIImageView {
}
MovableImageView.m
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:[self view]];
[self setCenter:location];
}
Each one of your two UIImageView should now be MovableImageView
i have an image view as background image.
I am seeking that in some place on image view touches would be enabled.
I started with this:
- (id)initWithTouchPoint:(CGRect )point
{
self = [super init];
if (self) {
touchFrame = point;
[self setAccessibilityFrame:touchFrame];
}
return self;
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
-(BOOL)canResignFirstResponder{
return YES;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self];
if (CGRectContainsPoint(touchFrame, touchLocation)) {
//[self setUserInteractionEnabled:NO];
}else{
//[self setUserInteractionEnabled:YES];
}
DLog(#"touchesBegan at x : %f y : %f",touchLocation.x,touchLocation.y);
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
}
Is it possible to let user touch over image view when user touches in touchFrame ?
Thank you.
Add UITapGestureRecognizer on UIImageView
UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(handleGesture:)];
[gesture setNumberOfTapsRequired:1];
[imageView setUserInteractionEnabled:YES];
[imageView addGestureRecognizer:gesture];
Now within the HandleGesture Method :
-(void)handleGesture:(UITapGestureRecognizer *)_gesture
{
if (_gesture.state == UIGestureRecognizerStateEnded)
{
CGPoint touchedPoint = [_gesture locationInView:self.view];
}
}
you can check now wether the touchedPoint within the handleGesture method are in the specified area or not and you can perform your desired task accordingly
You can try having a boolean variable as a class member say BOOL allowTouch initialised with value NO:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self];
if (CGRectContainsPoint(touchFrame, touchLocation)) {
allowTouch = YES;
}
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
if(allowTouch)
{
//handle moves here
}
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
allowTouch = NO;//you can put your condition too to end touches
}
It may help.