I have one base view A with size of (0,0,320,280), it contain another view B with size of
(100,100,50,50) and View B has one button and one image view(C) as sub view. image view frame is same as view B, button has added in B's top left corner.
My requirement is when we drag the B's bottom right corner its size has to increased or decreased.
if we drag the B from any other place except bottom right corner it has to move. view size should not be modified.
My problem is view B does not receive the touch action.
i added the code below. please guide me.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
//baseVw-------> view B//
if ([touch view]==baseVw)
{
touchStart = [[touches anyObject] locationInView:baseVw];
isResizingLR = (baseVw.bounds.size.width - touchStart.x < kResizeThumbSize && baseVw.bounds.size.height - touchStart.y < kResizeThumbSize);
isResizingUL = (touchStart.x <kResizeThumbSize && touchStart.y <kResizeThumbSize);
isResizingUR = (baseVw.bounds.size.width-touchStart.x < kResizeThumbSize && touchStart.y<kResizeThumbSize);
isResizingLL = (touchStart.x <kResizeThumbSize && baseVw.bounds.size.height -touchStart.y <kResizeThumbSize);
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches] anyObject];
CGPoint touchPoint = [[touches anyObject] locationInView:baseVw];
CGPoint previous=[[touches anyObject]previousLocationInView:baseVw];
float deltaWidth = touchPoint.x-previous.x;
float deltaHeight = touchPoint.y-previous.y;
if ([touch view]==baseVw)
{
if (isResizingLR)
{
baseVw.frame = CGRectMake(baseVw.frame.origin.x, baseVw.frame.origin.y,touchPoint.x + deltaWidth, touchPoint.y + deltaWidth);
}
else
{
CGPoint activePoint = [[touches anyObject] locationInView:baseVw];
// Determine new point based on where the touch is now located
CGPoint newPoint = CGPointMake(baseVw.center.x + (activePoint.x - touchStart.x),
baseVw.center.y + (activePoint.y - touchStart.y));
//--------------------------------------------------------
// Make sure we stay within the bounds of the parent view
//--------------------------------------------------------
float midPointX = CGRectGetMidX(baseVw.bounds);
// If too far right...
if (newPoint.x > baseVw.superview.bounds.size.width - midPointX)
newPoint.x = baseVw.superview.bounds.size.width - midPointX;
else if (newPoint.x < midPointX) // If too far left...
newPoint.x = midPointX;
float midPointY = CGRectGetMidY(baseVw.bounds);
// If too far down...
if (newPoint.y > baseVw.superview.bounds.size.height - midPointY)
newPoint.y = baseVw.superview.bounds.size.height - midPointY;
else if (newPoint.y < midPointY) // If too far up...
newPoint.y = midPointY;
// Set new center location
baseVw.center = newPoint;
}
}
}
View B probably does not receive any touch events because these are absorbed by the subview C. Assuming you implemented the touch methods in B you should also make sure that you set B as the firstResponder. Implement this:
-(BOOL)canBecomeFirstResponder
{
return YES;
}
And then call [self becomeFirstResponder]; after you add C as the subview. The code inside the touchesBegan/Moved doesn't matter if they are not being called (touch events not received).
Related
I have an ImageView that moves around the UIView, is it possible to detect collision of the ImageView and the view its self? For example the ImageView hits the side of the view I want it to run an action. -(void)restart {}
If this is possible can you detect which side it has collided with?
You can create a custom UIImageVIew and implement the methods touchBegan and touchMoved (don't forget to add [self setUserInteractionEnabled:YES] in your init method). Then set the rect you want to interact with :
customImageView.interactRect = myView.frame;
And in your customImageView you can add something like:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
lastPosition = [touch locationInView: self.superview];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
CGPoint position = [touch locationInView:self.superview];
CGRect currentFrame = self.frame;
currentFrame.origin = CGPointMake(currentFrame.origin.x + position.x - lastPosition.x, currentFrame.origin.y + position.y - lastPosition.y);
if (CGRectIntersectsRect(currentFrame, interactRect) && !CGRectIntersectsRect(self.frame, interactRect))
{
NSLog(#"I'm in for the first time");
if(self.frame.origin.x + self.frame.size.width <= interactRect.origin.x && currentFrame.origin.x + currentFrame.size.width > interactRect.origin.x)
{
NSLog(#"Coming from the left");
}
if(self.frame.origin.x >= interactRect.origin.x + interactRect.size.width && currentFrame.origin.x < interactRect.origin.x + interactRect.size.width)
{
NSLog(#"Coming from the right");
}
}
self.frame = currentFrame;
lastPosition = position;
}
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.)
I am developing an app, Which has feature that dragging and rotating the image view.
I have implemented to drag and rotate successfully by using below code
In touchesBegan Method
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
touchStart = [[touches anyObject] locationInView:imageView];
isResizingLR = (containerVw.bounds.size.width - touchStart.x < kResizeThumbSize && containerVw.bounds.size.height - touchStart.y < kResizeThumbSize);
}
In touchesMoved Method
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
CGPoint touchPoint = [[touches anyObject] locationInView:containerVw];
CGPoint previous=[[touches anyObject]previousLocationInView:containerVw];
UITouch *touch = [[event allTouches] anyObject];
if (isResizingLR) {
CGFloat currA = [self pointToAngleFromCenter:[touch locationInView:containerVw.superview]] ;
CGFloat prevA = [self pointToAngleFromCenter:[touch previousLocationInView:containerVw.superview]] ;
// the current value of the rotation angle
CGFloat tranA = atan2(containerVw.transform.b, containerVw.transform.a) ;
// the angle difference between last touch and the current touch
CGFloat diffA = currA - prevA ;
// the new angle resulting from applying the difference
CGFloat angle1 = tranA - diffA ;
CGAffineTransform t = CGAffineTransformMakeRotation(angle1) ;
containerVw.transform =t;
}
if (!isResizingLR) {
containerVw.center = CGPointMake(containerVw.center.x + touchPoint.x - touchStart.x, containerVw.center.y + touchPoint.y - touchStart.y);
}
}
My Problem
Above code is working fine until rotating the image view after dragging. In case if i drag the image view after rotating it. image view has gone away from screen.
In touchesEnd method i tried to print the image view frame. for example my image view frame at the beginning is (100,100,150,149) after rotating it the image view 160º frame has changed to (103,31,182,183) up to now its working fine.
After rotating it if try to move an image view, the image view has gone away from screen now the frame has changed to (615,-212,182,183)
Please guide me how do i resolve it.
Have a look at this project. This may help you. But here, the movement is handled by gestures and not by touch. It may solve your problem.
I want to detect a two-finger diagonal swipe that starts from the bottom right of the screen to the middle. I tried adding UISwipeGestureRecognizer with direction set as "UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionLeft" but to no vail as the handler is getting invoked even if I start the swipe from the middle of the screen to the top left.
Do I need to sub-class UIGestureRecognizer or can I handle this using touchesBegan and touchesMoved ?
You need to subclass it to use touchesBegan and touchesMoved anyway. I'd do UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionLeft like you said, then set up two CGRects, one for acceptable starting points, one for acceptable end points. Then use the UIGestureRecognizerDelegate method gestureRecognizer:shouldReceiveTouch:, and check if the touch point is in the acceptable start rect by using CGRectContainsPoint(). Then (I think) in your UISwipeGestureRecognizer subclass, override touchesEnded:withEvent:, and check if the end touch is in the acceptable rect. If it's not, set the state to UIGestureRecognizerStateCancelled (or however you're supposed to cancel a gesture). Also make sure the view it's attached to has its multipleTouchEnabled property set. I haven't actually tried this, but something of the sort should do it. Good luck!
EDIT
Actually, if you didn't want to have to worry about specific rect values for the acceptable start/end points, and make it device independent, you could do this:
//swap in whatever percentage of the screen's width/height you want in place of ".75f"
//set the origin for acceptable start points
CGFloat startRect_x = self.view.frame.size.width * .75f;
CGFloat startRect_y = self.view.frame.size.height * .75f;
//set the size
CGFloat rectWidth = self.view.frame.size.width - startRect_x;
CGFloat rectHeight = self.view.frame.size.height - startRect_y;
//make the acceptable start point rect
CGRect startRect = CGRectMake(startRect_x, startRect_y, rectWidth, rectHeight);
//set the origin for the accepable end points
CGFloat endRect_x = self.view.center.x - rectWidth/2;
CGFloat endRect_y = self.view.center.y - rectHeight/2;
//make the acceptable end point rect
CGRect endRect = CGRectMake(endRect_x, endRect_y, rectWidth, rectHeight);
the touches method of cause can do every Gesture, the Gesture is supported since ios3.2.
i can give you a simple code , you maybe modify by yourself.
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
isTwoFingersBegin = NO;
isTwoFingersEnd = NO;
UITouch *touch = [touches anyObject];
UIView *touchView = [touch view];
if ([touches count] == 2)
{
isTwoFingersBegin = YES;
}
touchStartPoint = [touch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
isSwip = YES;
}
#define TOUCH_MOVE_EFFECT_DIST 30
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject];
UIView *touchView = [touch view];
touchEndPoint = [touch locationInView:self.view];
if ([touches count] == 2)
{
isTwoFingersEnd = YES;
}
CGPoint deltaVector = CGPointMake(touchEndPoint.x - touchStartPoint.x, touchEndPoint.y - touchStartPoint.y);
if (fabsf(deltaVector.x) > TOUCH_MOVE_EFFECT_DIST
&&fabsf(deltaVector.y) > TOUCH_MOVE_EFFECT_DIST
&& isSwip &&isTwoFingersBegin&&isTwoFingersEnd) {
theSwipGesture=RightUpGesture;
}
else if (fabsf(deltaVector.x) <- TOUCH_MOVE_EFFECT_DIST
&& fabsf(deltaVector.y) <- TOUCH_MOVE_EFFECT_DIST
&& isSwip&&isTwoFingersBegin&&isTwoFingersEnd) {
theSwipGesture=LeftDownGesture;
}
isSwip = NO;
}
You can use a UIPanGestureRecognizer
- (void)viewPanned:(UIPanGestureRecognizer *)panGR
{
CGPoint translation = [panGR translationInView:self];
CGFloat threshold = self.bounds.size.width/2;
// Detect
Direction direction = DirectionUnknown;
if (translation.x > threshold) {
if (translation.y > threshold) {
direction = DirectionBottomRight;
} else if (translation.y < -threshold) {
direction = DirectionTopRight;
} else {
direction = DirectionRight;
}
} else if (translation.x < -threshold) {
if (translation.y > threshold) {
direction = DirectionBottomLeft;
} else if (translation.y < -threshold) {
direction = DirectionTopLeft;
} else {
direction = DirectionLeft;
}
} else {
if (translation.y > threshold) {
direction = DirectionBottom;
} else if (translation.y < -threshold) {
direction = DirectionTop;
}
}
}
One possible solution would be to map off a group of coordinates on the iPhone's screen where the swipe could potentially start, and another where it could potentially end. Then in the touchesBegan: and touchesMoved: methods, you could compare the starting and ending points of the swipe and determine whether it qualified as diagonal.
Thanks Guys!
I ended up writing custom code in touchesBegan, touchesMoved and touchesEnded and ot works like charm.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if ([touches count] == 2) {
CGPoint nowPoint = [[touches anyObject] locationInView:self];
if( nowPoint.x >= ALLOWED_X)
swipeUp = YES;
}
[super touchesBegan:touches withEvent:event];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
if ([touches count] == 2 && swipeUp) {
CGPoint nowPoint = [[touches anyObject] locationInView:self];
CGPoint prevPoint = [[touches anyObject] previousLocationInView:self];
if( nowPoint.x <= prevPoint.x && nowPoint.y <= prevPoint.y){
}
else {
swipeUp = NO;
}
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesEnded:touches withEvent:event];
CGPoint nowPoint = [[touches anyObject] locationInView:self];
if ([touches count] == 2 && swipeUp && nowPoint.x <= DELTA_X && nowPoint.y <= DELTA_Y) {
NSLog(#"Invoke Method");
}
swipeUp = NO;
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesCancelled:touches withEvent:event];
swipeUp = NO;
}
I'm trying to create a draggable image, but i'm trying to confine it's dragging to within a small square rather than the full screen. Could someone tell me where i'm going wrong?. I've placed the code that I have so far below:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if([touch view] == dot) {
CGPoint location = [touch locationInView:self.view];
dot.center = location;
if (location.x >10) {
location.x =10;
} else if (location.x <10) {
location.x = 10;
}
if (location.y >20) {
location.y =20;
} else if (location.y < 20) {
location.y = 20;
}
}
}
You are assigning location before you are making changes to it.
Apply your limits to location first then assign it to dot.
Also, your limits you are showing would lock your position to 10,20 since you are not allowing it to be more than 10 or less than 10. Likewise with 20.
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [[event allTouches] anyObject];
if([touch view] == dot) {
CGPoint location = [touch locationInView:self.view];
location.x = MIN(MAX(location.x, 0),10);
location.y = MIN(MAX(location.y, 0),20);
dot.center = location;
}
}
I have implemented an image dragging function recently like this. I use the PAN Gesture to move the image which results in two CGFloats "endPointX and endPointY". In the code below between the comments "Stay on Screen Check" and "End Stay on Screen check", I check if these are on the screen. If not I adjust them to prevent the image moving off the screen.
I hope that helps. If you want to move the image within a small part of the total screen then I would add the image to a holder subview and then check the holder view .bounds.size.width/height above instead.
CGFloat endPointX = translatedPoint.x + (.35*[(UIPanGestureRecognizer*)sender
velocityInView:self.view].x);
CGFloat endPointY = translatedPoint.y + (.35*[(UIPanGestureRecognizer*)sender velocityInView:self.view].y);
// Stay on the screen check
if(endPointX < 0) {
endPointX = 0;
} else if(endPointX > self.view.bounds.size.width) {
endPointX = self.view.bounds.size.width;
}
if(endPointY < 0) {
endPointY = 0;
} else if(endPointY > self.view.bounds.size.height) {
endPointY = self.view.bounds.size.height;
}
// End of the Stay on Screen check
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:.35];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
[[sender view] setCenter:CGPointMake(endPointX, endPointY)];
[UIView commitAnimations];