I'm a newbie to this and remaking an app. I am trying to use UITapGestureRecognizer. It works in the initial project file but not the new one. The only difference is that the old one uses a navigational controller but mine doesn't.
In the new one the self distance:location to:centre is stuck at 640 no matter where you press on the screen.
Can anyone help? I have no idea why it isn't working.
- (void)handleSingleTap:(UITapGestureRecognizer *)recognizer {
CGPoint location = [recognizer locationInView:[recognizer.view superview]];
CGPoint centre = CGPointMake(512,768 / 2);
NSInteger msg = [self distance:location to:centre];
NSLog(#"location to centre: %d", msg);
if ([self distance:location to:centre] < 330)
The part that looks suspicious to me is [recognizer.view superview].
When the gesture recognizer was added to self.view in a UIViewController that is not inside a container controller (e.g. a Navigation Controller) that view does not have a superview. If you send the superview message to self.view without a container view controller it will return nil.
So your message looked basically like this
CGPoint location = [recognizer locationInView:nil];
This will return the location in the window, which is also a valid CGPoint that tells you were you tapped the screen.
Since this didn't work I guess in [self distance:location to:centre] you do something that does only work with coordinates relative to the view. Maybe it's related to rotation, because the coordinates of the window don't rotate when you rotate the device.
Without knowing your code I'm not sure what the problem is, but it probably doesn't matter.
Just replace [recognizer.view superview] with recognizer.view.
Refer below Link, You may get your answer. It's an example if Gesture Recognition.
http://www.techotopia.com/index.php/An_iPhone_iOS_6_Gesture_Recognition_Tutorial
Related
I have added my NSScrollView over the content view of my NSWindow object. Now I need to know the mouse location over the scrollview.
I have tried the following. But nothing gives the correct location.
- (void)mouseDown:(NSEvent *)theEvent{
NSPoint eventLocation = [theEvent locationInWindow];
NSPoint locationInScroll = [inputScrollView convertPoint:eventLocation toView:nil];
//Both gives the wrong location.
}
The code is correct, assuming that inputScrollView is the document view and the NSScrollView itself.
Another potential problem could be if you change the orientation of the coordinate system in one of the views?
I've put a UIButton inside a custom UIView and the button is not receiving any touch events (it doesn't get into the highlighted state, so my problem is not about being unable to wire up a touch inside up handler). I've tried both putting it into the XIB in Interface Builder, and also tried programatically adding the UIButton into the UIView seperately, both ended with no luck. All my views are inside a UIScrollView, so I first though UIScrollView may be blocking them, so I've also added a button programatically exactly the same way I add my custom view into UIScrollView, and the button worked, elimination the possibility of UIScrollView could be the cause. My View's hiearchy is like this:
The button is over the image view, and the front layer isn't occupying my button completely, so there's no reason for me not be physically interacting with the button. At my custom view's code side, I'm creating my view as such:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
UIView *sub = [[[NSBundle mainBundle] loadNibNamed:#"ProfileView" owner:self options:nil] objectAtIndex:0];
[self addSubview:sub];
[sub setUserInteractionEnabled:YES];
[self setUserInteractionEnabled:YES];
CALayer *layer = sub.layer;
layer.masksToBounds = YES;
layer.borderWidth = 5.0;
layer.borderColor = [UIColor whiteColor].CGColor;
layer.cornerRadius = 30.0;
/*layer.shadowOffset = CGSizeZero;
layer.shadowRadius = 20.0;
layer.shadowColor = [[UIColor blackColor] CGColor];
layer.shadowOpacity = 0.8;
*/
}
return self;
}
I've tried all combinations of setUserInteractionsEnabled, and had no luck. (Yes, also set them to checked in Interface Builder too). I've also read in another question with a similar problem that I should try overriding 'canBecomeFirstResponder' to return 'YES' and I've also done that too. But the problem persists, I can't click the button. I've not given any special properties, settings to the button, it's just a regular one. My other objects in the view (labels below, image view behind the button etc.) are working properly without problems. What could be possibly wrong here?
Thanks,
Can.
UPDATE: Here is a quick reproduction of the problem: https://dl.dropbox.com/u/79632924/Test.zip
Try to run and click the button.
Looking at the test project, I believe your problem in the way you create TestView, you do not specify the frame for it, so basically the parent view is 0 size, and the subviews you see from XIB extending out of the parent view and thus do not get anything in responder chain.
You should either specify the frame when creating TestView, or adjust the frame after loading XIB file.
I have had this problem as well. The cause for me was that the UIButton superview frame was of height 0, so I believe that even though a touch was happening, it was not being passed down to the button.
After making sure that the button's superview took a larger rectangle as a frame the button actions worked.
The root cause for this problem on my side was a faulty auto layout implementation (I forgot to set the height constraint for the button's superview).
I've found the solution. I was initializing my custom view as:
MyView *view = [[MyView alloc] init];
I've initialized it instead with a frame of my view's size, and it started responding to events:
CGRect rect = CGRectMake(0,0,width,height);
MyView *view = [[MyView alloc] initWithFrame:rect];
Storyboard Solution
Just for anyone wanting a solution to this when using storyboards and constraints.
Add a constraint between the superview (containing the button) and the UIButton with an equal heights constraint.
In my case, I had selected embed UIButton in a UIView with no inset on the storyboard. Adding the additional height constraint between the UIButton and the superview allowed the UIButton to respond to touches.
You can confirm the issue by starting the View Debugger and visually confirm that the superview of the UIButton is not selectable.
(Xcode 11, *- Should also work in earlier versions)
I have a CCLayer subclass MyLayer in which I handle touch events:
(BOOL) ccTouchBegan:(UITouch *) touch withEvent:(UIEvent *) event
I set the content size of MyLayer instances like this:
`myLayer.contentSize = CGSizeMake(30.0, 30.0);`
I then add MyLayer instances as children of ParentLayer. For some reason I can tap anywhere on the screen and a MyLayer instance will detect the tap. I want to only detect taps on the visible portion/content size. How can I do this?
Are the MyLayer instances somehow inheriting a "tappable area" from somewhere else? I've verified that the contentSize of the instance just tapped is (30, 30) as expected. Perhaps the contentSize isn't the way to specify the tappable area of CCLayer subclass.
When the touch is enabled on a particular CCLayer, it receives all of the touch events in the window. That being said, if there are multiple layers, all layers will receive the same touches.
To alleviate this, obtain the location from the UITouch, convert it to Cocos2d coordinates, then check to see if it is within the bounds of the Layer you are concerned with.
Here's some code to work with:
CCLayer * ccl = [[CCLayer alloc] init];
CGPoint location = [touch locationInView:[touch view]];
location = [[CCDirector sharedDirector] convertToGL:location];
if (CGRectContainsPoint(CGRectMake(ccl.position.x - ccl.contentSize.width/2, ccl.position.y - ccl.contentSize.height/2, ccl.contentSize.width, ccl.contentSize.height), location)) {
//continue from there...
}
I have two instances of NSScrollView both presenting a view on the same content. The second scroll view however has a scaled down version of the document view presented in the first scroll view. Both width and height can be individually scaled and the original width - height constraints can be lost, but this is of no importance.
I have the synchronised scrolling working, even taking into account that the second scroll view needs to align its scrolling behaviour based on the scaling. There's one little snag I've been pulling my hairs out over:
As both views happily scroll along the smaller view needs to slowly catch up with the larger view, so that they both "arrive" at the end of their document at the same time. Right now this is not happening and the result is that the smaller view is at "end-of-document" before the larger view.
The code for synchronised scrolling is based on the example found in Apple's documentation titled "Synchronizing Scroll Views". I have adapted the synchronizedViewContentBoundsDidChange: to the following code:
- (void) synchronizedViewContentBoundsDidChange: (NSNotification *) notification {
// get the changed content view from the notification
NSClipView *changedContentView = [notification object];
// get the origin of the NSClipView of the scroll view that
// we're watching
NSPoint changedBoundsOrigin = [changedContentView documentVisibleRect].origin;;
// get our current origin
NSPoint curOffset = [[self contentView] bounds].origin;
NSPoint newOffset = curOffset;
// scrolling is synchronized in the horizontal plane
// so only modify the x component of the offset
// "scale" variable will correct for difference in size between views
NSSize ownSize = [[self documentView] frame].size;
NSSize otherSize = [[[self synchronizedScrollView] documentView] frame].size;
float scale = otherSize.width / ownSize.width;
newOffset.x = floor(changedBoundsOrigin.x / scale);
// if our synced position is different from our current
// position, reposition our content view
if (!NSEqualPoints(curOffset, changedBoundsOrigin)) {
// note that a scroll view watching this one will
// get notified here
[[self contentView] scrollToPoint:newOffset];
// we have to tell the NSScrollView to update its
// scrollers
[self reflectScrolledClipView:[self contentView]];
}
}
How would I need to change that code so that the required effect (both scroll bars arriving at an end of document) is achieved?
EDIT: Some clarification as it was confusing when I read it back myself: The smaller view needs to slow down when scrolling the first view reaches the end. This would probably mean re-evaluating that scaling factor... but how?
EDIT 2: I changed the method based on Alex's suggestion:
NSScroller *myScroll = [self horizontalScroller];
NSScroller *otherScroll = [[self synchronizedScrollView] horizontalScroller];
//[otherScroll setFloatValue: [myScroll floatValue]];
NSLog(#"My scroller value: %f", [myScroll floatValue]);
NSLog(#"Other scroller value: %f", [otherScroll floatValue]);
// Get the changed content view from the notification.
NSClipView *changedContentView = [notification object];
// Get the origin of the NSClipView of the scroll view that we're watching.
NSPoint changedBoundsOrigin = [changedContentView documentVisibleRect].origin;;
// Get our current origin.
NSPoint curOffset = [[self contentView] bounds].origin;
NSPoint newOffset = curOffset;
// Scrolling is synchronized in the horizontal plane so only modify the x component of the offset.
NSSize ownSize = [[self documentView] frame].size;
newOffset.x = floor(ownSize.width * [otherScroll floatValue]);
// If our synced position is different from our current position, reposition our content view.
if (!NSEqualPoints(curOffset, changedBoundsOrigin)) {
// Note that a scroll view watching this one will get notified here.
[[self contentView] scrollToPoint: newOffset];
// We have to tell the NSScrollView to update its scrollers.
[self reflectScrolledClipView:[self contentView]];
}
Using this method the smaller view is "overtaken" by the larger view when both scrollers reach a value of 0.7, which is not good. The larger view then scrolls past its end of document.
I think you might be approaching this in the wrong way. I think you should be getting a percentage of how far down each scroll be is scrolled in relation to itself and apply that to the other view. One example of how this could be done is this way using NSScroller's -floatValue:
NSScroller *myScroll = [self verticalScroller];
NSScroller *otherScroll = [otherScrollView verticalScroller];
[myScroll setFloatValue:otherScroll.floatValue];
I finally figured it out. The answer from Alex was a good hint but not the full solution as just setting the float value of a scroller doesn't do anything. That value needs translation to specific coordinates to which the scroll view needs to scroll its contents.
However, due to differences in size of the scrolled document view, you cannot just simply use this value, as the scaled down view will be overtaken by the "normal" view at some point. This will cause the normal view to scroll past its end of document.
The second part of the solution was to make the normal sized view wait with scrolling until the scaled down view has scrolled its own width.
The code:
// Scrolling is synchronized in the horizontal plane so only modify the x component of the offset.
NSSize ownSize = [[self documentView] frame].size;
newOffset.x = MAX(floor(ownSize.width * [otherScroll floatValue] - [self frame].size.width),0);
The waiting is achieved by subtracting the width of the scroll view from the width times the value of the scroller. When the scaled down version is still traversing its first scroll view width of pixels, this calculation will result in a negative offset. Using MAX will prevent strange effects and the original view will quietly wait until the value turns positive and then start its own scrolling. This solution also works when the user resizes the app window.
I’m not asking for givemesamplecodenow responses, just a nudge in the right direction would be much appreciated. My searches haven’t been any good.
I have a UIButton that I am able to move freely around the screen.
I would like to limit the drag area on this object so it can only be moved up and down or side to side. I believe I need to get the x,y coordinates of the boundaries and then restrict movement outside this area. But that’s a far as I have got. My knowledge doesn’t stretch any further than that.
Has anyone implemented something similar in the past?
Adam
So let's say you're in the middle of the drag operation. You're moving the button instance around by setting its center to the center of whatever gesture is causing the movement.
You can impose restrictions by testing the gesture's center and resetting the center values if you don't like them. The below assumes a button wired to an action for all Touch Drag events but the principle still applies if you're using gesture recognizers or touchesBegan: and friends.
- (IBAction)handleDrag:(UIButton *)sender forEvent:(UIEvent *)event
{
CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];
if (point.y > 200)
{
point.y = 200; //No dragging this button lower than 200px from the origin!
}
sender.center = point;
}
If you want a button that slides only on one axis, that's easy enough:
- (IBAction)handleDrag:(UIButton *)sender forEvent:(UIEvent *)event
{
CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];
point.y = sender.center.y; //Always stick to the same y value
sender.center = point;
}
Or perhaps you want the button draggable only inside the region of a specific view. This might be easier to define if your boundaries are complicated.
- (IBAction)handleDrag:(UIButton *)sender forEvent:(UIEvent *)event
{
CGPoint point = [[[event allTouches] anyObject] locationInView:self.someView];
if ([self.someView pointInside:point withEvent:nil])
{
sender.center = point;
//Only if the gesture center is inside the specified view will the button be moved
}
}
Presumably you'd be using touchesBegan:, touchesMoved:, etc., so it should be as simple as testing whether the touch point is outside your view's bounds in touchesMoved:. If it is outside, ignore it, but if it's inside, adjust the position of the button.
I suspect you may find this function useful:
bool CGRectContainsPoint ( CGRect rect, CGPoint point );