Let me start off by describing my situation. I have a main view that I wish to place a smaller scrollview subview in. Then later in code (in another method), I like to add some subviews (images and textviews) to that scrollview subview. And maybe even remove the image- and text-subviews later (in yet another method). So the image- and text-subviews ends up been a subview of a subview of the main view.
This is easily done, if it all happens inside the same method. But I can't seem to add a 3rd generation subview to the second subview from another method. Would expect something like:
[self.view.scrollviewSubview addSubview:anotherSubview];
How to target the scrollview-subview placed as subview in main view. Hope my question makes sense, it's really hard to describe in text.
I'm not sure to have understood ^^
But if your problem is to access a subview you don't have a pointer to, maybe you could set a tag to your subview
[ view setTag:9000 ];
Then later in your code you could search for this view with :
[ view viewWithTag:9000 ]
Don't forget that with viewWithTag you will get an UIView class. So if you need to get a specific class, you should cast it like
(MyViewSubclassed*)[ view viewWithTag:9000 ]
Good Luck !
Related
I have a simple question regarding the method removeFromSuperview()
When for example I use it to remove a UIView, do I remove also all of this view subviews?
I tried to search online but didn't find anything explanatory at least to me.
Yes. Basically, that is what a subview is. What you do to a superview, qua view, you do its subviews. Move it, hide it, show it, transform it, change its alpha, whatever.
Another way to think about it: what does it mean for a subview to have no superview in the interface? It means the subview is not in the interface. Well, you just took the superview out of the interface.
And we can go further. The superview owns the subview. If you remove the superview, by default, it is destroyed. In that case, the subview is destroyed too; it has no owner any more.
I was googling for a while and I found similar problems but when the custom View is inside a ScrollView, but that is not my case.
I have a custom view that consists of a UILabel behind a UITextField, so I can animate that label later.
The problem is that when I add a View in my ViewController and in the Identity Inspector I set the Class as my custom class, when I use the application the UITextField within my custom view does not receive the touches well and it takes time to gain focus and therefore to open the keyboard. The strange thing is that if I move that same arrangement of views to my main ViewController in Storyboard everything works fine. Why doesn't it do it when I place it using the described method?
I plans to reuse this custom view a lot, so putting logic and views in each ViewController is not an option.
Thanks in advance
Well, the problem was in the constraints of the container UIView. That means, the UIView in my main ViewController. The Height of the UIView was a little bit smaller than the space required for my custom view, so although my custom view seemed to draw correctly, it was not receiving the gestures correctly. The solution was simply increase the height to the correct value occupied by my custom View. Thanks a lot!
I have a UIView with a lot of components enclosed in it and would like to update some of them if the view is removed or if its parent view controller is popped/pushed. Is it possible for a UIView to get this information
Similar to the method in UIViewController
-(void)viewWillAppear;
Would like something like
-(void)UIViewWillAppear;
Edit for some comments I saw:
I'll explain a bit more
But I have a special case where the UIView needed to add a "floating view" on top of itself (Imagine a zooming/panning/scrolling UISCrollView subclass with floater on top of itself) such that when it scrolled the floating view stayed in place relative to the superview. I tried recalculating the new origin of the "floater" inside of the -(void)layoutSubviews method but the re-placement was very choppy. In order to solve this choppyness problem, the custom UIView added the floating view (which in theory is its subview) as a subview for its superview (a bit of a tongue twister :) ).
Now arises a problem when the custom UIView is removed (or its containing view controller is pushed offscreen). How can the special UISCrollView remove the floating view from its superView.
You can override willMoveToSuperview: to find out when a view is inserted into a hierarchy and when it's removed. That's probably not what you want since the view can be part of a hierarchy and not be inserted by itself.
To find out if it's on screen use willMoveToWindow:. If the argument is non-nil the view just became part of a visible view hierarchy.
If you need to do something after the change use didMoveToWindow:.
UIView do not appear/disappear 'randomly' or when they want - your view controllers (or code) control this. So you should find out when you show them, and call code you need.
The UIView class reference has some kvo observing change.
By implementing -(void)willRemoveSubview:(UIView *)subview you could see the other way round.
UPDATE After reading the explanations:
I hope I understood correctly. I did something similiar time ago, but with a UITableView rather than a UIScrollView (but they are quite the same underneath).
It was like a popup detail view. I solved, as you already did, by adding the detail view to the UITableView superview, and then I added a close UIButton in the detail view, with a corresponding IBOutlet:
#interface CustomUIView : UIView
#property(nonatomic,weak) IBOutlet UIButtonView *closingButton;
-(void)closeDetail:(IBAction)action;
#end
and the action was just:
-(void)closeDetail:(IBAction)action {
// do your cleaning/change to the detail subviews
[self removeFromSuperview]; // <-- clsoe the detail view
}
sdsds
Basically, I want to be able to click all the Subviews in the Image below...
I want to be able to tap the Subviews of View B but View A is in the way even though View A Subviews are not blocking the views below. Is this possible? In other words I want to be able to tap through the transparent parts of a view even though its frame/bounds cover that area. View B is under View A in a ScrollView.
thanks,
austin
The solution is to subclass View A (if it's not a custom view already) and override pointInside:withEvent.
Return YES if the specified point is inside one of View A's sub-views, or NO otherwise. When pointInside:withEvent returns NO the system will continue to try other views until it finds one that claims the point is inside it, then it will call hitTest:withEvent to see which inner-view to send the touches to (the default behaviour).
is there a possibility to determine if an uiview obj is going to be displayed. imagine: you have 2 uiviews in an uiscrollview. now you are going to switch per gesture from the first view to the second. the first view now is NOT in the viewport. now you are going to go back to the first view. and now I want to be notified that this view is in viewport, or is redisplayed. the same has to be for the second view. I have not found any callback or something like this.
You make sure your UiViewController overrides viewWillAppear: (before it appears this method is called) or viewDidAppear: (after this method is called).
See: http://developer.apple.com/iphone/library/documentation/uikit/reference/UIViewController_Class/Reference/Reference.html#//apple_ref/occ/instm/UIViewController/viewWillAppear:
That depends what you mean by "switch". If one view is just scrolled out of the visible area of the scrollview, but still remains attached as a subview to it, then you may want to check if the bounds of your view overlap those of the scrollviews visible area.
You could do this by using UIScrollView Delegate's scrollViewDidScroll: method to implement a check for overlaps while the user is scrolling.
If however your view is actually removed from the viewstack, then you may want to subclass UIView and implement willMoveToSuperview: to check if the view has been added to the scrollview again.