How to find out the touch screen position - iphone

I am developing one application. In that I am using one UIImageView and I am changing the position of the UIImageView every 0.5 seconds using below code.
[NSTimer scheduledTimerWithTimeInterval:0.5
target: self
selector:#selector(moveImage)
userInfo: nil repeats:YES];
-(void) moveImage
{
//[image1 setCenter: CGPointMake(634, 126)];
CGFloat x = (CGFloat) (arc4random() % (int) self.view.bounds.size.width);
CGFloat y = (CGFloat) (arc4random() % (int) self.view.bounds.size.height);
CGPoint squarePostion = CGPointMake(x, y);
img.center=squarePostion;
}
Now i can touch the screen. What i need to find out is my touch location and that imageview location both are correct or not.

use this
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self.view];
if ([touch view] == photo1) {
//photo1 is image view give tag to it
if( photo1.tag==3)
{
NSLog(#"You have been touched image view");
}
photo1.center = touchLocation;
}
}

//it used to find the point in view
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch * touch = [touches anyObject];
CGPoint pos = [touch locationInView: [UIApplication sharedApplication].keyWindow];
NSLog(#"%f,%f",pos.x, pos.y);
}

Related

UITouch, Drag and Drop not working at all

I have a UIView and on the top of him I've got UIButton, UITableView and UINavigationBar. what I want to do is, when you click on the UIButton and drag it, all the view will move to the left side only, until the screen ends. I mean that you can drag the view to the left and when you stop touching, the view will stop where your finger stopped touching the screen.
I can't do it, he shows me only the "Touches Began 1" and thats it. what seems to be my problem here?
Thanks alot everyone!
float oldX, oldY;
BOOL dragging;
- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
NSLog("Touches Began 1");
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self.view];
if (CGRectContainsPoint(btnOpen.frame, touchLocation))
{
NSLog("Touches Began 2");
dragging = YES;
oldX = touchLocation.x;
oldY = touchLocation.y;
}
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self.view];
if (dragging)
{
NSLog("Dragging!");
CGRect frame = mainView.frame;
frame.origin.x = mainView.frame.origin.x + touchLocation.x - oldX;
frame.origin.y = mainView.frame.origin.y + touchLocation.y - oldY;
mainView.frame = frame;
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog("Touches Ended!");
dragging = NO;
}
- (void)viewDidLoad
{
[btnOpen addTarget:self action:#selector(touchesBegan:withEvent:) forControlEvents: UIControlEventTouchDown];
[btnOpen addTarget:self action:#selector(touchesMoved:withEvent:) forControlEvents: UIControlEventTouchDragInside];
[btnOpen addTarget:self action:#selector(touchesEnded:withEvent:) forControlEvents: UIControlEventTouchUpInside | UIControlEventTouchUpOutside];
}
You are asking for the coordinates of the touch in relation to the frame of main view
CGPoint touchLocation = [touch locationInView:self.view];
And then you ask if the location of the touchLocation is within the frame of the buttons frame
if (CGRectContainsPoint(btnOpen.frame, touchLocation))
In another words. You are checking if the touch was within the bounds of the button but you check by the coordinates of the touch made on the main view instead of the button.
So this is what you should do:
CGPoint touchLocation = [touch locationInView:btnOpen];
- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
NSLog("Touches Began 1");
for (UITouch *touch in touches) {
//UITouch *touch = [[event allTouches] anyObject];
CGPoint touchLocation = [touch locationInView:self.view];
if (CGRectContainsPoint(btnOpen.frame, touchLocation))
{
NSLog("Touches Began 2");
//dragging = YES;
oldX = touchLocation.x;
oldY = touchLocation.y;
}
}
}
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
// UITouch *touch = [[event allTouches] anyObject];
for (UITouch *touch in touches) {
CGPoint touchLocation = [touch locationInView:self.view];
if (CGRectContainsPoint(btnOpen.frame, touchLocation))
{
NSLog("Dragging!");
CGRect frame = mainView.frame;
frame.origin.x = mainView.frame.origin.x + touchLocation.x - oldX;
frame.origin.y = mainView.frame.origin.y + touchLocation.y - oldY;
mainView.frame = frame;
}
}
}
Try like this i think it will be helpful to you.

How to set minimum & maximum y value?

I am implementing a draggable UIView in my application. The codes I have worked fine but I would like to set a restricted area the UIView can be moved.
My codes:
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view;
startX = camview.center.x;
startY= location.y - camview.center.y;
}
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view];
location.y =location.y - startY;
location.x = startX;
camview.center = location;
}
}
So how can I set the minimum and maximum y value that the UIView can be dragged?
Thanks!
If you are interested in making sure the view frame doesn't go over or under a certain y value you could do the following,
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
CGFloat minY, maxY; //The position in your self.view you are interested in
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == camview)
{
CGPoint location = [touch locationInView:self.view];
location.y = location.y - startY;
location.y = MIN(location.y,maxY); //Always <= maxY
location.y = MAX(location.y,minY); //Always >= minY
location.x = startX;
camview.center = location;
}
}

Drag View from the point you touch it iPhone

I know how to drag a view or object:
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == ViewMain)
{
CGPoint location = [touch locationInView:self.view];
ViewMain.center = location;
}
}
but I would like to start dragging that view or image from the point where I touched it. for example if I drag (I highlighted the view and placed blue on the cursor):
the moment I start dragging if I drag the mouse 20 px to the right for example then I would like the view to also drag 20 px instead of:
maybe I have to change the center of the view to the point where I fist touch it. How could I do that?
In other words I would like to do something like when you drag the apps on the iPad:
float startX = 0;
float startY = 0;
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == ViewMain)
{
CGPoint location = [touch locationInView:self.view];
startX = location.x - ViewMain.center.x;
startY = ViewMain.center.y;
}
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if( [touch view] == ViewMain)
{
CGPoint location = [touch locationInView:self.view];
location.x =location.x - startX;
location.y = startY;
ViewMain.center = location;
}
}

Rotation based on touch problem

I'm making a simple dial that rotates as you drag your finger across it. It rotates great, but it also rotates when i touch anywhere on the screen and drag my finger.
How can i restrict the first touches to be only inside my imageview object? or where am i going wrong?
this is my code of trouble:
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
UIImage *image1 = [UIImage imageNamed:#"nav#2x.png"];
wheelfrom = [[UIImageView alloc] initWithImage:image1];
wheelfrom.frame =CGRectMake(10, -130, 300, 300);
[self addSubview:wheelfrom];
}
return self;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch =[[[event allTouches] allObjects] lastObject];
firstLoc = [touch locationInView:self];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch =[[[event allTouches] allObjects] lastObject];
CGPoint curLoc = [touch locationInView:self];
float fromAngle = atan2( firstLoc.y-wheelfrom.center.y,
firstLoc.x-wheelfrom.center.x );
float toAngle = atan2( curLoc.y-wheelfrom.center.y,
curLoc.x-wheelfrom.center.x );
float newAngle = angle + (toAngle - fromAngle);
CGAffineTransform cgaRotate = CGAffineTransformMakeRotation(newAngle);
wheelfrom.transform = cgaRotate;
angle = newAngle;
}
Thanks for your help!
You try like this,
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:self.view];
if(CGRectContainsPoint(wheelfrom.frame, location))
{
//do your things
}
}
You can try by checking if the point of touch is within the frame of the image view.Do what you want only if its yes.
Inside -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event, check the firstLoc is within your range.

UIView drag (image and text)

Is it possible to drag UIView around the iOS screen while it has both image and text? e.g. small cards. Could you point me to the similar (solved) topic? I haven't found any.
This is what a neat solution, based on pepouze's answer, would look like (tested, it works!)
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *aTouch = [touches anyObject];
CGPoint location = [aTouch locationInView:self];
CGPoint previousLocation = [aTouch previousLocationInView:self];
self.frame = CGRectOffset(self.frame, (location.x - previousLocation.x), (location.y - previousLocation.y));
}
While UIView does not have a built-in support for moving itself along the user dragging, it should be not so difficult to implement it. It is even easier when you are only dealing with dragging on the view, and not other actions such as tapping, double tapping, multi-touches etc.
First thing to do is to make a custom view, say DraggableView, by subclassing UIView. Then override UIView's touchesMoved:withEvent: method, and you can get a current dragging location there, and move the DraggableView. Look at the following example.
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *aTouch = [touches anyObject];
CGPoint location = [aTouch locationInView:self.superview];
[UIView beginAnimations:#"Dragging A DraggableView" context:nil];
self.frame = CGRectMake(location.x, location.y,
self.frame.size.width, self.frame.size.height);
[UIView commitAnimations];
}
And because all subviews of the DraggableView object will be moved, too. So put all your images and texts as subviews of the DraggableView object.
What I implemented here is very simple. However, if you want more complex behaviors for the dragging, (for example, the user have to tap on the view for a few seconds to move the view), then you will have to override other event handling methods (touchesBegan:withEvent: and touchesEnd:withEvent) as well.
An addition to MHC's answer.
If you don't want the upper left corner of the view
to jump under your finger, you can also override touchesBegan
like this:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *aTouch = [touches anyObject];
offset = [aTouch locationInView: self];
}
and change MHC's touchesMoved to:
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *aTouch = [touches anyObject];
CGPoint location = [aTouch locationInView:self.superview];
[UIView beginAnimations:#"Dragging A DraggableView" context:nil];
self.frame = CGRectMake(location.x-offset.x, location.y-offset.y,
self.frame.size.width, self.frame.size.height);
[UIView commitAnimations];
}
you should also define CGPoint offset in the interface:
#interface DraggableView : UIView
{
CGPoint offset;
}
EDIT:
Arie Litovsky provides more elegant solution that allows you to ditch the ivar: https://stackoverflow.com/a/10378382/653513
Even though rokjarc solution works, using
CGPoint previousLocation = [aTouch previousLocationInView:self.superview];
avoids the CGPoint offset creation and the call to touchesBegan:withEvent:
Here is a solution to drag a custom UIView (it can be scaled or rotated through its transform), which can hold images and/or text (just edit the Tile.xib as required):
- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:self];
CGPoint previous = [touch previousLocationInView:self];
if (!CGAffineTransformIsIdentity(self.transform)) {
location = CGPointApplyAffineTransform(location, self.transform);
previous = CGPointApplyAffineTransform(previous, self.transform);
}
self.frame = CGRectOffset(self.frame,
(location.x - previous.x),
(location.y - previous.y));
}
This work for me. My UIView rotated and scaled
- (void) touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:self];
CGPoint previous = [touch previousLocationInView:self];
if (!CGAffineTransformIsIdentity(self.transform)) {
location = CGPointApplyAffineTransform(location, self.transform);
previous = CGPointApplyAffineTransform(previous, self.transform);
}
CGRect newFrame = CGRectOffset(self.frame,
(location.x - previous.x),
(location.y - previous.y));
float x = CGRectGetMidX(newFrame);
float y = CGRectGetMidY(newFrame);
self.center = CGPointMake(x, y);
}