I am making a a dragging code in which I am dragging button, now the problem is when I start dragging it slowly it works cool, but when I started dragging it bit fast its not working good cause button dropped during drag.
How can I increase the speed of drag?
- (void)wasDragged:(UIButton*)button withEvent:(UIEvent*)event{
CGPoint previousLocation;
CGPoint location;
UITouch *touch = [[event touchesForView:button] anyObject];
previousLocation = [touch previousLocationInView:button];
location = [touch locationInView:button];
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
button.center = CGPointMake(button.center.x + delta_x,button.center.y + delta_y);
}
simply you can just adjust the delta
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
delta_x *= 1.5; //the factor of the speed
delta_y *= 1.5;
button.center = CGPointMake(button.center.x + delta_x,button.center.y + delta_y);
why you don't you just set button.center coordonates as location.x and location.y? beacause location.x and location.y are the coordonates of where your finger is, and there should be the center of button
Related
I have an UIButton that I've creates programmatically. Actually it should'n be UIButton, I just need to have possibility to mark some area above the image.
So the features I need it - move object and resize it. For this i have 2 methods:
- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
UIControl *control = sender;
UITouch *t = [[event allTouches] anyObject];
CGPoint pPrev = [t previousLocationInView:control];
CGPoint p = [t locationInView:control];
CGPoint center = control.center;
center.x += p.x - pPrev.x;
center.y += p.y - pPrev.y;
control.center = center;
}
- (void)objScale:(UIPinchGestureRecognizer *)recognizer
{
UIView *pinchView = recognizer.view;
CGRect bounds = pinchView.bounds;
CGPoint pinchCenter = [recognizer locationInView:pinchView];
pinchCenter.x -= CGRectGetMidX(bounds);
pinchCenter.y -= CGRectGetMidY(bounds);
CGAffineTransform transform = pinchView.transform;
transform = CGAffineTransformTranslate(transform, pinchCenter.x, pinchCenter.y);
CGFloat scale = recognizer.scale;
transform = CGAffineTransformScale(transform, scale, scale);
transform = CGAffineTransformTranslate(transform, -pinchCenter.x, -pinchCenter.y);
pinchView.transform = transform;
recognizer.scale = 1.0;
}
Scale works ok. Moving looks ok until I change the size of object - when i increase object it become moves slower than finger, and vice versa - if object smaller than original it moves faster than finger. why it works like this?
I think you should get startPoint and startCenter in
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
// get startPoint and startCenter here
}
- (void) objMove:(id) sender withEvent:(UIEvent *) event
{
UIControl *control = sender;
UITouch *t = [[event allTouches] anyObject];
CGPoint p = [t locationInView:control];
startCenter.x += p.x - startPoint.x;
startCenter.y += p.y - startPoint.y;
control.center = startCenter;
}
Change your code like this, maybe it works.
Your center is current center, p is current point, pPrev is previous point.
current center adds previous point moved size is wrong.
You should get relative distance, not dynamic distance.
I am trying to drag a UITextView object with touch ! but I have a problem , I need when user touches the custom view , the touching event begins, but touching methods works only on self.view . here is my code :
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog(#"touch began ");
UITouch *touch = [touches anyObject];
startingX = [touch locationInView:_captureView].x;
startingY = [touch locationInView:_captureView].y;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint currentPoint = _mText.frame.origin;
float xForView, yForView;
UITouch *touch = [touches anyObject];
float newX = [touch locationInView:_captureView].x;
float deltaX;
if(startingX > newX){
deltaX = startingX - newX;
xForView = currentPoint.x - deltaX;
} else if(newX > startingX){
deltaX = newX - startingX;
xForView = currentPoint.x + deltaX;
} else xForView = currentPoint.x;
float newY = [touch locationInView:_captureView].y;
float deltaY;
if(startingY > newY){
deltaY = startingY - newY;
yForView = currentPoint.y - deltaY;
} else if(newY > startingY){
deltaY = newY - startingY;
yForView = currentPoint.y + deltaY;
} else yForView = currentPoint.y;
CGRect newFrame = CGRectMake(xForView, yForView, _mText.frame.size.width, _mText.frame.size.height);
_mText.frame = newFrame;
startingX = newX;
startingY = newY;
}
my textView is not editable all views are userInteractionEnabled
Write your touches began method and touches moved method inside the your custom text view and try to adjust the frame.
I have added a subview to a UIScrollView. When I zoom into the scroll view I want to pan around the subview.
In touchesBegan: I'm getting the initial location of the touch and then touchesMoved: I am able to determine how much to move the subview. It works perfectly when zoomscale is 1.0. However, when it is zoomed the pointer "breaks out" of the subview which it is intended to move (illustration here - pointer location is ilustrated as marquee tool).
The center of the view should be on pointer location, and not in it's current position! px and py variables ensure that wherever on the subview is clicked, while dragging it postion of the pointer always stays the same. illustration
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:self];
location.x = location.x * self.zoomScale;
location.y = location.y * self.zoomScale;
px = location.x;
py = location.y;
if ([touch view] == rotateView) {
self.scrollEnabled = NO;
return;
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint location = [touch locationInView:self];
location.x = location.x * self.zoomScale;
location.y = location.y * self.zoomScale;
if ([touch view] == rotateView) {
rotateView.center = CGPointMake(rotateView.center.x + (location.x - px), rotateView.center.y + (location.y - py));
px = location.x;
py = location.y;
return;
}
}
Instead of the approach you're taking, make the subview another UIScrollView and let it handle the panning.
(You may wish to set scrollEnabled = NO on your subview until zooming has occurred.)
Hi I am looking to make my UIButton be able to be draggable only around a circle I created through a draw rect. I may need to make a circle path instead of the circle shape however I'm not quite sure about the approach to take as I am new to this. Here is the code I have and I only want the button to be dragged around that circle or invisible path. Any help or examples would be extremely helpful. Thank You!
Edit: I used part of the answer below below but I am not sure how to get this to work correctly. I want it to be the same size as my circle that I created so I am happy to create just a circle path and put it on top of the circle that I made.
//Button Code
timeSetButton = [UIButton buttonWithType:UIButtonTypeCustom];
[timeSetButton addTarget:self
action:nil
forControlEvents:UIControlEventTouchDown];
[timeSetButton setImage:[UIImage imageNamed:#"testButton.png"] forState: UIControlStateNormal];
timeSetButton.frame = CGRectMake(0,415,50,50);
[self.view addSubview:timeSetButton];
//Button Listener
[timeSetButton addTarget:self action:#selector(wasDragged:withEvent:)
forControlEvents:UIControlEventTouchDragInside];
//Draggable Button Code
// get the touch
UITouch *touch = [[event touchesForView:timeSetButton] anyObject];
// get delta
CGPoint previousLocation = [touch previousLocationInView:timeSetButton];
CGPoint location = [touch locationInView:timeSetButton];
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
// move button
timeSetButton.center = CGPointMake(timeSetButton.center.x + delta_x,
timeSetButton.center.y + delta_y);
// enforce constraint on locations, by...
// working out the distance from the centre of the circle
CGPoint vectorFromCentreOfCircle =
CGPointMake(150,150);
CGFloat distanceFromCentreOfCircle = hypotf(vectorFromCentreOfCircle.x, vectorFromCentreOfCircle.y);
// working out what you'd need to multiply that distance by in order
// to get the specified radius
CGFloat correctionMultiplier = 20 / distanceFromCentreOfCircle;
// adjust vector from centre of circle
vectorFromCentreOfCircle.x *= correctionMultiplier;
vectorFromCentreOfCircle.y *= correctionMultiplier;
// move button one more time
timeSetButton.center = CGPointMake(
200 + vectorFromCentreOfCircle.x,
200 + vectorFromCentreOfCircle.y);
Here is the Circle Shape
circleView = [[CircleView alloc] initWithFrame:CGRectMake(55, 100, 260, 260)];
circleView.backgroundColor = [UIColor clearColor];
[self.view addSubview:circleView];
[self.view sendSubviewToBack:circleView];
I actually needed the same and was watching your code. What you actually need to do is fetch the angle of the actual circle and then calculate the needed x and y on that. This is how I have done it:
UIButton *button = (UIButton *) sender;
UITouch *touch = [[event touchesForView:button] anyObject];
//Drawing the circle
CGPoint arcCenter = CGPointMake(385.0f, 700.0f);
CGFloat arcRadius = 140.0f;
// get delta
CGPoint previousLocation = [touch previousLocationInView:button];
CGPoint location = [touch locationInView:button];
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
// move button
button.center = CGPointMake(button.center.x + delta_x, button.center.y + delta_y);
CGFloat angle = atan2((button.center.y - arcCenter.y), (button.center.x - arcCenter.x));
button.center = CGPointMake(arcCenter.x + arcRadius * cos(angle), arcCenter.y + arcRadius * sin(angle));
This gives me when I add a drag to a button the actual needed behavior. I used Touch Drag Outside and Inside to avoid the button to stop when you move your finger too much away from the button. I hope it will help you too.
For this sort of thing it's probably sufficient just to add a quick bit of code after you've moved the button to enforce the constraint that it must be on the circle. E.g.
// move button
timeSetButton.center = CGPointMake(button.center.x + delta_x,
button.center.y + delta_y);
// enforce constraint on locations, by...
// working out the distance from the centre of the circle
CGPoint vectorFromCentreOfCircle =
CGPointMake(timeSetButton.center.x - centreOfCircle.x,
timeSetButton.center.x - centreOfCircle.y);
CGFloat distanceFromCentreOfCircle =
hypotf(vectorFromCentreOfCircle.x, vectorFromCentreOfCircle.y);
// working out what you'd need to multiply that distance by in order
// to get the specified radius
CGFloat correctionMultiplier = radiusOfCircle / distanceFromCentreOfCircle;
// adjust vector from centre of circle
vectorFromCentreOfCircle.x *= correctionMultiplier;
vectorFromCentreOfCircle.y *= correctionMultiplier;
// move button one more time
timeSetButton.center = CGPointMake(
centreOfCircle.x + vectorFromCentreOfCircle.x,
centreOfCircle.y + vectorFromCentreOfCircle.y);
You can do this simply by knowing the distance of touchPoint from the center of the view
I'll make the following modification in your code. See if this works
- (void)wasDragged:(UIButton *)button withEvent:(UIEvent *)event
{
// get the touch
UITouch *touch = [[event touchesForView:button] anyObject];
// get delta
CGPoint previousLocation = [touch previousLocationInView:button];
CGPoint location = [touch locationInView:button];
//calculate center of button in superView
CGPoint buttonCenter = CGPointMake(button.frame.origin.x+(button.frame.size.width/2.0f),
button.frame.origin.y+(button.frame.size.height/2.0f));
//calculate the distance of current touchPoint from buttonCenter
CGFloat diffx = location.x - buttonCenter.x;
CGFloat diffy = location.y - buttonCenter.y;
CGFloat distance = sqrtf((diffx*diffx)+(diffy*diffy));
//check if the distance is within the radius of circle.
//assuming that your button is always a square to make
//perfect circle within it.
CGFloat radius = button.frame.size.width/2.0f;
if(radius >= distance)//this makes a circular check.
{
CGFloat delta_x = location.x - previousLocation.x;
CGFloat delta_y = location.y - previousLocation.y;
// move button
timeSetButton.center = CGPointMake(button.center.x + delta_x,
button.center.y + delta_y);
}
}
I'm trying these two methods to move and rotate an UIView. Both methods work separately but if I rotate and then move the UIView it disappears.
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
CGRect rect = self.aView.frame;
UITouch *touch = [touches anyObject];
CGPoint pPoint = [touch previousLocationInView:self.view];
CGPoint cPoint = [touch locationInView:self.view];
float deltaX = cPoint.x - pPoint.x;
float deltaY = cPoint.y - pPoint.y;
rect.origin.x = rect.origin.x + deltaX;
rect.origin.y = rect.origin.y + deltaY;
self.aView.frame = rect;
}
- (void)rotate:(UIRotationGestureRecognizer *) recognizer {
CGFloat rotation = angle + recognizer.rotation;
NSLog(#"%f", angle * 180 / M_PI);
self.aView.transform = CGAffineTransformMakeRotation (rotation);
if (recognizer.state == UIGestureRecognizerStateEnded)
angle = rotation;
}
Gesture recognisers take priority over touchMoved, so it's hard to use them both with the same view.
Use a UIPanGestureRecognizer instead of touchMoved to handle dragging the UIView. You can then get the UIPanGestureRecognizer and UIRotationGestureRecognizer to cooperate with one another by implementing the
– gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:
method, which is defined in the UIGestureRecognizerDelegate protocol.