Is there any easy way to detect these kinds of gestures for iPhone?
I can use touchesBegan, touchesMoved, touchesEnded. But how can I implement the gestures? thz u.
You will using UISwipeGestureRecognizer Object to detect the Touch and direction of Swipe In
UIView or anywhere in iphone sdk.
UISwipeGestureRecognizer *rightRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(rightSwipeHandle:)];
rightRecognizer.direction = UISwipeGestureRecognizerDirectionRight;
[rightRecognizer setNumberOfTouchesRequired:1];
//add the your gestureRecognizer , where to detect the touch..
[view1 addGestureRecognizer:rightRecognizer];
[rightRecognizer release];
UISwipeGestureRecognizer *leftRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(leftSwipeHandle:)];
leftRecognizer.direction = UISwipeGestureRecognizerDirectionLeft;
[leftRecognizer setNumberOfTouchesRequired:1];
[view1 addGestureRecognizer:leftRecognizer];
[leftRecognizer release];
- (void)rightSwipeHandle:(UISwipeGestureRecognizer*)gestureRecognizer
{
NSLog(#"rightSwipeHandle");
}
- (void)leftSwipeHandle:(UISwipeGestureRecognizer*)gestureRecognizer
{
NSLog(#"leftSwipeHandle");
}
I think this the Better solution for your problem
You are on the right track. In touchesBegan you should store the position where the user first touches the screen.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
self.startPosition = [touch locationInView:self];
}
Similar code in touchesEnded gives you the final position. By comparing the two positions you can determine the direction of movement. If the x-coordinate has moved beyond a certain tolerance you have a left or right swipe.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint endPosition = [touch locationInView:self];
if (startPosition.x < endPosition.x) {
// Right swipe
} else {
// Left swipe
}
}
You do not need touchesMoved unless you want to detect and track a swipe while the user is still touching the screen. It may also be worth testing that the user has moved a minimal distance before deciding they have performed a swipe.
If you're willing to target iPhone OS 3.2 or later (all iPads or updated iPhones), use the UISwipeGestureRecognizer object. It will do this trivially, which is wickedly cool.
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'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 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.
I've created a puzzle engine for iPad (iOS SDK 4.2)
I have a PuzzleViewController that controls a UIView (rootView) that holds a smaller UIView (puzzleView) and twelve puzzle pieces (PuzzlePieceView class extends UIImageView).
The ideia is very simple. The puzzlePieces are around the puzzleView and are picked and dragged to the puzzleView. When the pieces are picked they double they're size and are centered to place where the finger is touching.
When they're dropped in the right place they stay put (they're removed from rootView and added as subviews to the puzzleView) if they're drop in the wrong place they return to the original position and size.
Currently I'm overriding touches Began/Moved/Ended/Cancelled in the PuzzlePieceView class so that each PuzzlePiece controls its own movements.
here's what they do
#pragma mark UIResponder overriding
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"PuzzlePiece touchesBegan");
if (!isDeployed) {
if (self.initialSize.width == 0 || self.initialSize.height ==0) { //if there is still no initial size
self.initialSize = self.frame.size;
}
NSLog(#"self.initialLocation.x %f %f", self.initialLocation.x, self.initialLocation.y);
if (self.initialLocation.x == 0. || self.initialLocation.y == 0.) { //if there is still no initial location
self.initialLocation = self.center; //record the initial location
}
UITouch *touch = [[event allTouches] anyObject];
self.center = [touch locationInView:self.superview]; //set the center of the view as the point where the finger touched it
[self.superview bringSubviewToFront:self]; //the piece brings itself as frontMostView so that it is always visible and never behind any other piece while moving
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"PuzzlePiece touchesMoved");
if (self.frame.size.width == self.initialSize.width) {
self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.image.size.width, self.image.size.height);
}
if (!isDeployed) {
UITouch *touch = [[event allTouches] anyObject];
self.center = [touch locationInView:self.superview]; //set the center of the view as the point where the finger moved to
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"PuzzlePiece touchesEnded");
if (!isDeployed) {
UITouch *touch = [[event allTouches] anyObject];
NSLog(#"point %# x%f y%f", self.puzzleView, [touch locationInView:self.puzzleView].x, [touch locationInView:self.puzzleView].y);
if (CGRectContainsPoint(self.dropZone,[touch locationInView:self.puzzleView])) {
[self removeFromSuperview];
[self.puzzleViewController addPiece:self];
self.center = self.finalCenter;
self.isDeployed = YES;
}
else {
[self restoreToInitialSize];
[self restoreToInitialPosition];
}
}
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"PuzzlePiece touchesCancelled");
if (!isDeployed) {
[self restoreToInitialSize];
[self restoreToInitialPosition];
}
}
#pragma mark -
Seemed pretty easy and it was.
I've got only one bug left.
When I try to make an horizontal move on any puzzlePiece the touch gets cancelled.
This only happens when the move is started in a fast way. If i touch the piece and wait for a moment (about a second) the pieces move perfectly.
The pieces also move perfectly in the vertical direction.
I've tried not changing the puzzlePiece size when the view is first touched bu the bug remains...
I found the solution to this.
One of my team-mates registered a UISwipeGestureRecognizer in the RootView instead of the specific subview were the swipeGesture should be recognized.
I'm developing a game that will use the force of the swipe as a variable user input.
I read from the documentation that on the touchesEnded event, I can get the allTouches array which is a list of the user touches collected from touchesBegan. From this I plan to get the last two touches to get the direction of the swipe. I will also get the time interval between touchesBegan and touchesEnded, from which I will get the speed of the swipe. I will use the direction and the speed to calculate the force of the swipe.
What I'd like to know is: is there a better way to do this? Is this already encapsulated in a library call somewhere?
Thanks in advance.
Solve like this
- (void)rotateAccordingToAngle:(float)angle
{
[spinWheel setTransform:CGAffineTransformRotate(spinWheel.transform, angle)];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[spinWheel.layer removeAllAnimations];
previousTimestamp = event.timestamp;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
if (touch.view==spinWheel)
{
UITouch *touch = [touches anyObject];
CGPoint center = CGPointMake(CGRectGetMidX([spinWheel bounds]), CGRectGetMidY([spinWheel bounds]));
CGPoint currentTouchPoint = [touch locationInView:spinWheel];
CGPoint previousTouchPoint = [touch previousLocationInView:spinWheel];
CGFloat angleInRadians = atan2f(currentTouchPoint.y - center.y, currentTouchPoint.x - center.x) - atan2f(previousTouchPoint.y - center.y, previousTouchPoint.x - center.x);
[self rotateAccordingToAngle:angleInRadians];
CGFloat angleInDegree = RADIANS_TO_DEGREES(angleInRadians);
revolutions+= (angleInDegree/360.0f);
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
if (touch.view==spinWheel)
{
NSTimeInterval timeSincePrevious = event.timestamp - previousTimestamp;
CGFloat revolutionsPerSecond = revolutions/timeSincePrevious;
NSLog(#"%.3f",revolutionsPerSecond);
[self startAnimationWithRevolutions:revolutionsPerSecond forTime:5.0f];
}
revolutions = 0;
}
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
spinWheel.userInteractionEnabled = TRUE;
if (timerUpdate) {
[timerUpdate invalidate];
timerUpdate = nil;
}
}
-(void)updateTransform{
spinWheel.transform = [[spinWheel.layer presentationLayer] affineTransform];
}
-(void)startAnimationWithRevolutions:(float)revPerSecond forTime:(float)time
{
spinWheel.userInteractionEnabled = FALSE;
float totalRevolutions = revPerSecond * time;
timerUpdate = [NSTimer scheduledTimerWithTimeInterval:0.1f target:self selector:#selector(updateTransform) userInfo:nil repeats:YES];
[CATransaction begin];
[CATransaction setValue:[NSNumber numberWithFloat:time] forKey:kCATransactionAnimationDuration];
CABasicAnimation* spinAnimation = [CABasicAnimation
animationWithKeyPath:#"transform.rotation"];
CGAffineTransform transform = spinWheel.transform;
float fromAngle = atan2(transform.b, transform.a);
float toAngle = fromAngle + (totalRevolutions*4*M_PI);
spinAnimation.fromValue = [NSNumber numberWithFloat:fromAngle];
spinAnimation.toValue = [NSNumber numberWithFloat:toAngle];
spinAnimation.repeatCount = 0;
spinAnimation.removedOnCompletion = NO;
spinAnimation.delegate = self;
spinAnimation.timingFunction = [CAMediaTimingFunction functionWithName:
kCAMediaTimingFunctionEaseOut];
[spinWheel.layer addAnimation:spinAnimation forKey:#"spinAnimation"];
[CATransaction commit];
}
I've accomplished something along these lines rather simply by just comparing [touch locationInView:self] to [touch previousLocationInView:self] in touchesEnded of the Class (subclass of UIView) of the object that will be moved. This will give you a vector with location, direction & rough sense of velocity at the moment user released finger from the iPhone.
You could use a UIPanGestureRecognizer which has function velocityInView. See https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIPanGestureRecognizer_Class/
Rather than using allTouches on the UIEvent, you should use the touches set that you get in the call to your UIView's (or other UIResponder's) touchesEnded:withEvent: method. This ensures that you don't get touches that belong to other views.
Since the iPhone is a multi-touch device, the set contains all the touches that are associated with that event. In other words, if the user is touching the screen with two fingers, there should be two UITouch objects in the set, etc.
This means that the set does not contain all the points traversed since a touch began until it ended. To track that, you have to save the start point and time in touchesBegan:withEvent:, and then when the touch ends you calculate the speed based on that.
Note that if the set contains several points (which means the user is touching the screen with several fingers), you have to try to keep track of which UITouch object corresponds to which finger. You will want to do this in touchesMoved:withEvent:.
Since you get the touches in a set, you can't use an index or some key value to keep track of the touches you are interested in. I believe that the recommended way of doing this is to just assume that the touch that is closest to the point you saved on the previous event comes from the same finger. If you want to be more exact you can also use the UITouch's previousLocationInView: method.
If you're lazy, you can also simply do [[touches allObjects] objectAtIndex:0] and hope that this will give you the right touch (ie the one originating from the same finger) on each event. This actually often works, but I don't think you should use it in production code, especially not if you're trying to create an app with multi-touch functionality.