I have an empty View-Based app. I'd like to do something with the x,y coordinates of every touch down on the screen. How do I do this?
Override the
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
function (from the NSRespondrer class). You can override it from your view class. The 'touches' variable hold a set of 'UITouch' instances that you can query for the location in the view.
Related
I have this newly created Empty project using XCode5. Added a storyboard with one blank View Controller. Created a custom view controller class.
Here's the question. How could I log or display the touches on this project?
You can use method - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
I have a uicollectionviewcontroller which I use to create a small toolbar at the bottom of the screen. I add the view of the uicollectionviewcontroller to another viewcontroller's view. My problem is that it won't forward touch events to a view underneath it. I did move it to the bottom and that worked for a while but now I need to use 2 uicollection views.
How am I supposed to forward touch events to views beneath a uicollectionviewcontroller's view?
In case the question is still relevant, the following can be used to achieve touch forwarding.
Subclass UICollectionView
Overwrite - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
[super touchesEnded:touches withEvent:event];
[self.yourCustomDelegate forwardTouches:touches withEvent:(UIEvent *)event];
}
That is how UICollectionView can keep its ability to respond to user interaction, and the same time forward received touches.
As i think you can add your toolbar as footer of UICollectionView and it will work
have a look into this link How to Add Header and Footer View in UICollectionView
I am trying to understand if something like this is possible and if yes how can i go about achieving this.
i want to create a UIView that it is a container for other views that respond based on the below picture. i know that a UIView is a container of other UIViews. what i want to be able to do is to be able to touch on a UIImageView and when i am dragging it in the main View, if it gets out of bounds on one side, to be shown on exactly the opposite direction like shown on the image. i hope i managed to explain the question correctly.
Click Here for the Description
You can achieve that very easily by implementing the container UIView's touch methods:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
In touchesMoved you can check for your UIImageView's origin. If it crosses the boundaries (x, y less than 0 or bigger than the container's dimensions) then simply reposition its frame by your desired offset.
My question might sound rather strange, but still I didn't find any reference and I really need help.
so my point is, I have a ViewController which has a collection of UIViews, to be specific a subclass of UIView with
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
overridden
from this event i want to load a specific data (according on the UIView touched) on the UIViewController's child UIWebView
Is there a way to address parent ViewControllers children from the UIView that receives the action
Or am I looking into a completely wrong direction.
Any hel will be greatly appreciated, thanks in advance.
You can use delegate for example:
#protocol someProtocol
- (void)recivedTouch:(UITouch *)touch fromUIView:(UIView *)uiView;
in you view:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
[self.delegate recivedTouch:touch fromUIView:self];
}
View controller implemed method from delegate:
- (void)recivedTouch:(UITouch *)touch fromUIView:(UIView *)uiView
{
if (uiView == self.someView)
{
// do some stuff with uiWebView
}
}
try to look at it differently. Your touchesBegan shouldn't do anything which is not connected with the view. Your view is just a UI component, it shouldn't control application flow (data loading). That's the job of the view controller.
Look how UIButton is implemented. The button does not do anything when clicked. The controller has to tell it "this is the method that should be called when the user clicks you"
There are two ways how to tell the view what it should do for a specific action - creating a delegate or passing a selector that should be called.
Consider also extending UIControl, which has most of the actions already implemented.
Alternatively use NSNotificationCenter: Send and receive messages through NSNotificationCenter in Objective-C?
Send a message from your view, hook the message from your controller. Notificationas can get a bit messy though, the delegate is probably a cleaner solution
I have added an NSOpenGLView to my MainMenu.xib file, and have implemented drawRect to draw to it, this works great, so far so good.
How do I detect touches on the screen? I imagine I could perhaps dump some transparent buttons or something over the NSOpenGLView area in Interface Builder?
The application is simple, i just need to know which area of a grid has been touched.
No need to add transparent buttons or overlays.
I'm assuming this is for the phone because you mentioned Cocoa Touch, but I'm not aware of NSOpenGLView for the phone. You need to look at the Apple example and create an EAGLView by overriding +layerClass in your subclass thus:
+ (Class)layerClass {
return [CAEAGLLayer class];
}
Next, Make sure "User Interaction Enabled" is checked in IB.
Finally, implement the touch method calls:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;
These will tell you where users touched the surface, and with how many fingers. You can do the rest from there. Try creating the template OpenGL project and looking at that. In addition, Jeff LaMarche has some good iPhone OpenGL tutorials on his blog: http://iphonedevelopment.blogspot.com/