What is the best way to trigger a method based on Pan gesture value?
I want to trigger a method when my pan location x is between 500 to 600. How do people normally handle this??
You need to override gestureRecognizerShouldBegin. Then you can detect translation.x and see where the values fall between.
- (BOOL)gestureRecognizerShouldBegin:(UIPanGestureRecognizer *)panGestureRecognizer {
CGPoint translation = [panGestureRecognizer translationInView:self.view];
if (translation.x > 500 && translation.x < 600)
[self callCustom];
return true;
}
- (void) callCustom {
//do what you need to do
}
I assume you have a method that handles the pan gesture. Make that method look something like this.
- (void)handlePan:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateChanged) {
CGPoint movement = [recognizer translationInView:self.view];
if (movement.x >= 500 && movement.x <= 600) {
[self methodToCall];
}
}
}
Related
I've been working on this code for quite a while now but it just feels like one step forward and two steps back. I'm hoping someone can help me.
I'm working with Sprite Kit so I have a Scene file that manages the rendering, UI and touch controls. I have an SKNode thats functioning as the camera like so:
_world = [[SKNode alloc] init];
[_world setName:#"world"];
[self addChild:_world];
I am using UIGestureRecognizer, so I add the ones I need like so:
_panRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:#selector(handlePanFrom:)];
[[self view] addGestureRecognizer:_panRecognizer];
_pinchRecognizer = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:#selector(handlePinch:)];
[[self view] addGestureRecognizer:_pinchRecognizer];
The panning is working okay, but not great. The pinching is the real problem. The idea for the pinching is to grab a point at the center of the screen, convert that point to the world node, and then move to it while zooming in. Here is the method for pinching:
-(void) handlePinch:(UIPinchGestureRecognizer *)sender {
if (sender.state == UIGestureRecognizerStateBegan) {
_tempScale = [sender scale];
}
if (sender.state == UIGestureRecognizerStateChanged) {
if([sender scale] > _tempScale) {
if (_world.xScale < 6) {
//_world.xScale += 0.05;
//_world.yScale += 0.05;
//[_world setScale:[sender scale]];
[_world setScale:_world.xScale += 0.05];
CGPoint screenCenter = CGPointMake(_initialScreenSize.width/2, _initialScreenSize.height/2);
CGPoint newWorldPoint = [self convertTouchPointToWorld:screenCenter];
//crazy method why does this work
CGPoint alteredWorldCenter = CGPointMake(((newWorldPoint.x*_world.xScale)*-1), (newWorldPoint.y*_world.yScale)*-1);
//why does the duration have to be exactly 0.3 to work
SKAction *moveToCenter = [SKAction moveTo:alteredWorldCenter duration:0.3];
[_world runAction:moveToCenter];
}
} else if ([sender scale] < _tempScale) {
if (_world.xScale > 0.5 && _world.xScale > 0.3){
//_world.xScale -= 0.05;
//_world.yScale -= 0.05;
//[_world setScale:[sender scale]];
[_world setScale:_world.xScale -= 0.05];
CGPoint screenCenter = CGPointMake(_initialScreenSize.width/2, _initialScreenSize.height/2);
CGPoint newWorldPoint = [self convertTouchPointToWorld:screenCenter];
//crazy method why does this work
CGPoint alteredWorldCenter = CGPointMake(((newWorldPoint.x*_world.xScale - _initialScreenSize.width)*-1), (newWorldPoint.y*_world.yScale - _initialScreenSize.height)*-1);
SKAction *moveToCenter = [SKAction moveTo:alteredWorldCenter duration:0.3];
[_world runAction:moveToCenter];
}
}
}
if (sender.state == UIGestureRecognizerStateEnded) {
[_world removeAllActions];
}
}
I've tried many iterations of this, but this exact code is what is getting me the closest to pinching on a point in the world. There are some problems though. As you get further out from the center, it doesn't work as well, as it pretty much still tries to zoom in on the very center of the world. After converting the center point to the world node, I still need to manipulate it again to get it centered properly (the formula I describe as crazy). And it has to be different for zooming in and zooming out to work. The duration of the move action has to be set to 0.3 or it pretty much won't work at all. Higher or lower and it doesn't zoom in on the center point. If I try to increment the zoom by more than a small amount, it moves crazy fast. If I don't end the actions when the pinch ends, the screen jerks. I don't understand why this works at all (it smoothly zooms in to the center point before the delay ends and the screen jerks) and I'm not sure what I'm doing wrong. Any help is much appreciated!
Take a look at my answer to a very similar question.
https://stackoverflow.com/a/21947549/3148272
The code I posted "anchors" the zoom at the location of the pinch gesture instead of the center of the screen, but that is easy to change as I tried it both ways.
As requested in the comments below, I am also adding my panning code to this answer.
Panning Code...
// instance variables of MyScene.
SKNode *_mySkNode;
UIPanGestureRecognizer *_panGestureRecognizer;
- (void)didMoveToView:(SKView *)view
{
_panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePanFrom:)];
[[self view] addGestureRecognizer:_panGestureRecognizer];
}
- (void)handlePanFrom:(UIPanGestureRecognizer *)recognizer
{
if (recognizer.state == UIGestureRecognizerStateBegan) {
[recognizer setTranslation:CGPointZero inView:recognizer.view];
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [recognizer translationInView:recognizer.view];
translation = CGPointMake(-translation.x, translation.y);
_mySkNode.position = CGPointSubtract(_mySkNode.position, translation);
[recognizer setTranslation:CGPointZero inView:recognizer.view];
} else if (recognizer.state == UIGestureRecognizerStateEnded) {
// No code needed for panning.
}
}
The following are the two helper functions that were used above. They are from the Ray Wenderlich book on Sprite Kit.
SKT_INLINE CGPoint CGPointAdd(CGPoint point1, CGPoint point2) {
return CGPointMake(point1.x + point2.x, point1.y + point2.y);
}
SKT_INLINE CGPoint CGPointSubtract(CGPoint point1, CGPoint point2) {
return CGPointMake(point1.x - point2.x, point1.y - point2.y);
}
How can i write custom gesture for increase the size of the view in all the direction (i.e) in origin side and size of the view.
Example:
the user should touch the view in any one of the corner. either near to origin side or view end side.
Example: View frame size is (100,100,200,200). and minimum touch distance is 15 pixel from any side.
so, if the user touch location is (X=15,Y=40) in
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
method means that touch near to the origin side.
same if the user touch location is (X=15, Y=190) in
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
method means the touch is near to the size side.
My code:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];
if([touches count] != self.touchMinimumCount ||
[[touches anyObject] tapCount] > self.tapMinimumCount)
{
self.state = UIGestureRecognizerStateFailed;
return;
}
self.startPoint = [[touches anyObject] locationInView:self.view];
self.viewFrame = self.view.frame;
if(((self.startPoint.x - self.view.bounds.origin.x) <= self.minimumTouchDistance) ||
((self.startPoint.y - self.view.bounds.origin.y) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.x - self.view.bounds.size.width)) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.y - self.view.bounds.size.height)) <= self.minimumTouchDistance))
{
self.state = UIGestureRecognizerStatePossible;
if(((self.startPoint.x - self.view.bounds.origin.x) <= self.minimumTouchDistance) ||
((self.startPoint.y - self.view.bounds.origin.y) <= self.minimumTouchDistance) )
{
self.currentTouchPosition = touchPositionIsOrigin;
}
else if(((ABS(self.startPoint.x - self.view.bounds.size.width)) <= self.minimumTouchDistance) ||
((ABS(self.startPoint.y - self.view.bounds.size.height)) <= self.minimumTouchDistance))
{
self.currentTouchPosition = touchPositionIsSize;
}
}
else
{
self.state = UIGestureRecognizerStateFailed;
}
}
My gesture possible state setting if the touch in side the touch distance only.
Now i want to resize the view frame according to the user finger move.
if the user touch the origin side and move towards the left direction means, want to change the origin.x of the view and the width also want to increase.
if the user touch the origin side and move towards the top direction means, want to change the origin.y of the view and the width also want to increase.
if the user touch the origin side and move towards the right direction means, want to change the origin.x of the view.
if the user touch the origin side and move towards the bottom direction means, want to change the origin.y of the view.
if the user touch the size side and move towards the left direction means, want to reduce the width of the view.
if the user touch the size side and move towards the top direction means, want to reduce the height of the view.
if the user touch the size side and move towards the right direction means, want to increase the width of the view.
if the user touch the size side and move towards the bottom direction means, want to increase the height of the view.
this all change according tho the user finger in that view while moving.
My code:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
if(self.state == UIGestureRecognizerStateFailed) return;
direction currentDirection;
CGPoint currentLocation = [[touches anyObject] locationInView:self.view];
if(self.state == UIGestureRecognizerStatePossible ||
self.state == UIGestureRecognizerStateChanged)
{
if((currentLocation.x - self.startPoint.x) > 0)
{
currentDirection = directionRight;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginX = // need to implement.
distanceInSizeX = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeX = // need to implement.
}
}
else if((currentLocation.x - self.startPoint.x) < 0)
{
currentDirection = directionLeft;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginX = // need to implement.
distanceInSizeX = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeX = // need to implement.
}
}
else if((currentLocation.y - self.startPoint.y) >= 0)
{
currentDirection = directionBottom;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginY = // need to implement.
distanceInSizeY = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeY = // need to implement.
}
}
else if((currentLocation.y - self.startPoint.y) < 0)
{
currentDirection = directionTop;
self.state = UIGestureRecognizerStateChanged;
if(self.currentTouchPosition == touchPositionIsOrigin)
{
distanceInOriginY = // need to implement.
distanceInSizeY = // need to implement.
}
else if(self.currentTouchPosition == touchPositionIsSize)
{
distanceInSizeY = // need to implement.
}
}
else
{
currentDirection = directionUnknown;
}
self.originPoint = CGPointMake(distanceInOriginX, distanceInOriginY);
self.sizePoint = CGPointMake(distanceInSizeX, distanceInSizeY);
}
}
i mentioned the // need to implement. where ever i want the code for to achieve the functionality which i mentioned in that points. so, kindly help to go ahed.
if my was is wrong means, share the best way to do the same type of gesture.
any example is there also kindly share here. thanks in advance....
If you want to scale the size of a view, then use UIPinchGestureRecognizer. An example code is given here
UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:#selector(scale:)];
pinchRecognizer.delegate = self;
[self addGestureRecognizer:pinchRecognizer];
handler method is
#pragma mark - Gesture handling functions
-(void)scale:(UIPinchGestureRecognizer*)recognizer {
if ([recognizer state] == UIGestureRecognizerStateBegan) {
_lastScale = 1.0;
}
CGFloat scale = 1.0 - (_lastScale - [recognizer scale]);
CGAffineTransform currentTransform = self.imgView.transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
self.imgView.transform = newTransform;
_lastScale = [recognizer scale];
}
In my code I need to find the coordinate a user touched and is currently panning.
I've set up the following code based on - Touch Coordinates from UIPanGestureRecognizer
It looks as following:
CGPoint pos = [gestureRecognizer locationInView:[gestureRecognizer view]];
However the values returned by this method are either negative, or larger than the view's own frame. How can that be? What am I doing wrong?
Thanks
Try this one its giving me the coordinates of x and y
-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
CGPoint touchPoint = [gestureUp locationOfTouch:0 inView:gestureUp.view];
if (touchPoint.y <= 160)
{
if (gestureUp.direction == UISwipeGestureRecognizerDirectionUp)
{
NSLog(#"the location x...%f",touchPoint.x);
NSLog(#"the location y...%f",touchPoint.y);
}
else
{ }
}
return YES;
}
I'm trying to use UIPanGestureRecognizer to slide a button between two points (like a volume slider). The following code allows me to slide the button back and forth, but the button doesn't stop at the same point every time (i.e., when I slide it to the right, sometime it stops where it's supposed to, sometimes it stops +/- 10 pixels from where it's supposed to). What am I doing wrong?
- (void)handlePan:(UIPanGestureRecognizer *)recognizer {
CGPoint location = [recognizer locationInView:self];
// 1
if (recognizer.state == UIGestureRecognizerStateBegan) {
// if the gesture just started, record current center location
_originalCenter = self.sliderButton.center;
}
// 2
if (recognizer.state == UIGestureRecognizerStateChanged) {
// move the checkmarks and main label based on touch
//CGPoint translation = [recognizer translationInView:self];
// move slider button
if (location.x < 70 + 178 && location.x > 70) {
self.sliderButton.center = CGPointMake(location.x, _originalCenter.y);
}
// determine whether the item has been dragged far enough to initiate a removal
if (location.x > 170 + 70) {
_draggedToEnd = YES;
} else {
_draggedToEnd = NO;
}
}
// 3
if (recognizer.state == UIGestureRecognizerStateEnded) {
if (_draggedToEnd) {
// notify the delegate that this item should be deleted
[self buttonDraggedToEnd];
}
}
}
I'm using UIPinchGestureRecognizer to detect pinch gestures, something like:
- (void) initPinchRecon {
UIPinchGestureRecognizer *pinchRecognizer = [[[UIPinchGestureRecognizer alloc]
initWithTarget:self
action:#selector(Perform_Pinch:)] autorelease];
[self addGestureRecognizer:pinchRecognizer];
[pinchRecognizer setScale:20.0f];
}
- (void) Perform_Pinch:(UIPinchGestureRecognizer*)sender{
NSLog(#"PINCH");
}
And it works well to detect a simple pinch gesture: It's possible to determine (or define myself) the angle or orientation of the pinch gesture ?, for example, to differentiate between an horizontal and an vertical pinch gesture ?
A very simple solution is to implement the gesture handler like this:
-(void)handlePinchGesture:(UIPinchGestureRecognizer *)recognizer {
if (recognizer.state != UIGestureRecognizerStateCancelled) {
if (recognizer.numberOfTouches == 2) {
CGPoint firstPoint = [recognizer locationOfTouch:0 inView:recognizer.view];
CGPoint secondPoint = [recognizer locationOfTouch:1 inView:recognizer.view];
CGFloat angle = atan2(secondPoint.y - firstPoint.y, secondPoint.x - firstPoint.x);
// handle the gesture based on the angle (in radians)
}
}