Okay, so the subject talks for itself - I need to change default scrollbar with my custom image. I've been looking for a solution that doesn't require you to write your own ScrollView class or use hacks like creating an UIView with scrollbar image and repositioning it as you scroll.
One solution I liked was to use a simple UIScrollView category and to access scrollbars as UIScrollView's subviews: http://leonov.co/2011/04/uiscrollviews-scrollbars-customization/#comment-7909 For some reason, though, this one doesn't work for me. When I create UIScrollView and get its subviews array only views that I manually add to scrollview are shown there. I cannot access scrollbars iterating through subviews array. For example, this code:
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(10,10,100,100)];
scrollView.userInteractionEnabled = YES;
scrollView.bounces = NO;
scrollView.showsHorizontalScrollIndicator = YES;
NSLog(#"Subviews count is %d", [[scrollView subviews] count]);
will log "Subviews count is 0". Or, if I add X elements to scrollview, "Subviews count is X". Any ideas?
UIScrollbar scroll views are only created when the view is scrolling. They are removed again when the view stops scrolling. That's probably why you can't find them with your category.
You could move your scrollview subview traversing code into the scrollview delegate's scrollViewDidScroll method, which would mean it gets executed whenever the view is scrolling.
I can't help but feel that this is all a horrible and unneccesary hack though, and you'd be better off hiding the scrollbars and implementing them yourself using the delegate methods to determine when to show and hide your custom scrollbar view and the contentOffset property to determine where to position it.
Related
I feel like I have touched on every single possible cause for stopping this, but I have a UIScrollView in my Storyboard hooked up with an outlet and in the viewDidLoad I set the contentSize so that I can scroll (yes bigger than my frame size)!
However, whatever I change, I just can't scroll! I have a couple of textfields in my scrollview and bouncing enabled so I can see that when testing its moves up and down with my subviews in it but whatever I set the contentSize to I just can't scroll.
Anything I might be missing/should check? Is this a known issue with UIScrollView being used in a storyboard?
Whats even stranger is, I can do something like this:
[scrollView setBackgroundColor:[UIColor blueColor]]; and I have a blue scroll view! But setting content size fails.
Edit
My only code (otherwise scrollview is just dropped into storyboard view controller):
-(void)viewDidAppear:(BOOL)animated
{
[scrollView setContentSize:CGSizeMake(320, 640)];
}
Logged frame, comes out as expected:
width: 320.00
height: 504.00
Edit 2
Turns out that removing any subviews of the scroll view in my storyboard lets it scroll just fine. If I add any subview to it at all via the storyboard, even a blank brand new UIButton it just won't apply the contentSize/allow scrolling.
use ViewDidLayoutSubview
- (void)viewDidLayoutSubviews
{
[_scrollView setContentSize:CGSizeMake(320, 500)];
}
UIViewController's method invoke sequence is as below
awakeFromNib
viewDidLoad
viewWillAppear
viewWillLayoutSubviews
viewDidLayoutSubviews
viewDidAppear
viewDidLoad is not a good place to put code that relies on frame sizes of IB objects. If you log the contentSize of your scroll view in viewDidLoad, you will see that it's (0,0). Move the code (where you set the content size) to viewDidAppear, and it will work properly.
Check these
User Interaction enabled
Outlet connected
Included contentsize greater than bounds
scrolling Enabled
eg
scrollView.contentSize = CGSizeMake(320, 640);
My storyboard looks like this for scrollview [working]
I had exactly the same line of code in viewDidAppear and it did not work
Moved it to viewDidLayoutSubviews and it worked correctly.
[scrollView setContentSize:CGSizeMake(320, 500)];
Thanks trick14 for the answer.
The issue is most probably with Auto Layout. UIScrollView needs special attention when using AutoLayout.
Quick-fix - bind one of the scroll's subviews to the top AND bottom space of it's superview (the scroll view).
Long story:
Questions on SO:
UIScrollView not scrolling regardless of large contentSize,
UIScrollView will not scroll, even after content size set,
UIScrollView doesn't use autolayout constraints
Apple's Documentation:
https://developer.apple.com/library/ios/technotes/tn2154/_index.html
Trip14's answer worked for me. In swift I coded it as:
override func viewDidLayoutSubviews() {
(self.view as! UIScrollView).contentSize = CGSizeMake(600, 600)
}
This seems to be a similar issue. Other Story
It might be an issue with auto layout or constraints in the storyboard.
the best way with the storyboard.:
When I set my UIScrollView to be the main view within Interface Builder, the scrolling works as expected. However, when I add the UIScrollView as a subview of UIView the scroll does not work.
So it seems my trouble begins when the UIScrollView is added as a subview to UIView.
The "User Interaction Enabled" it true for both view.
I though perhaps I might have to do something with in touchesBegan something lake passing the touches to the UIScrollView, but have not had much luck with that.
Has anyone seen this before?
scrollView.delegate = scrollView; //or nil may work
It's always good to show a complete working code snippet:
// in viewDidLoad:
//UIScrollview *myScrollView;
UIView_descendent *contentView;
// scrollview won't scroll unless content size explicitly set
[myScrollView setContentSize:contentView.frame.size];
I have not found a way to set contentSize in IB.
I've got a detail view with various labels and such providing information about a place (address, phone, etc.). The information provided is taller than an iPhone screen so they're all in a UIScrollView (itself inside a UIView) that allows you to swipe up and down to see everything.
I also have an MKMapView inside the scrollview. When it's not attached to anything in Interface Builder it moves up and down with the scrollview, as it should, staying in it's correct relative position to the other controls in the scrollview. You can play with the map, zooming and panning it, etc. and it shows your current location by default.
However, as soon as I hook it to an MKMapView variable in IB, the mapview no longer scrolls with the scrollview. Instead it literally just sits in the position it's originally displayed in (bottom of the view, with a little of the map hidden below the bottom of the view) and the scrollview scrolls up and down behind it.
What's happening here? I've tried changing a bunch of the mapview's and scrollview's properties in IB, but it has no effect. The only thing I haven't tried is just creating the mapview entirely in code, but that doesn't seem like an obvious solution.
EDIT: Sorry to everyone about the expired bounty. I got hung up in other areas of the project and couldn't get back here until now. I didn't know it would expire.
FURTHER EDIT: Well, I figured out my problem. For reasons completely unknown to me I had
[self.view addSubview:mapView];
in the viewcontoller's ViewDidLoad. Once it was hooked up then that line of code would (obviously) make the map a subview of my of view, effectively yanking it out of the scrollview.
Stupid mistake, sorry to have wasted your time (and the bounty). I'll delete this question after I think the answerers have had a chance to see the result.
Looking like as you are using the ScrollView,you need to scrolling facility in your DetailView.
Instead of using the ScrollView ,I had an alternative of this ....
You can try your hard luck by using the TableView instead of ScrollView.
Just take all the labels and mapView in a single View and then put that view in the header of the TableView.
like this :
UITableView
--> View
------>All Labels // Inside the singleView
------>MKMApView // At bottom of the View
Still You can play with the map, zooming and panning it, etc. and it will show your current location by default.
Hope this alternative can solve your problem.......
All the Best
If hooking up an outlet in IB is breaking an otherwise working view, you might be able to try this to locate the view at runtime:
- (UIView *) findClass:(Class) aClass inView:(UIView *) aSuperview {
for ( UIView *view in aSuperview.subviews ) {
if ( [view isKindOfClass: aClass] ) break;
if ( ( view = [self findClass: aClass inView: aSuperview] ) ) break;
}
return view;
}
- (void) viewDidLoad {
MkMapView *map = [self findClass: [MkMapView class] inView: self.view];
}
I figured out my problem. For reasons completely unknown to me I had
[self.view addSubview:mapView];
in the viewcontoller's ViewDidLoad. Once it was hooked up then that line of code would (obviously) make the map a subview of my of view, effectively yanking it out of the scrollview.
Do you have setContentSize property set to the content's size in the viewDidLoad method of the UIViewController?
I have a UIScrollView which I create and size dynamically using...
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width , length);
I then add subviews to the UIScrollView.
I do have scrollView.showsVerticalScrollIndicator = YES;
When scrolling the scroll indicator never appears.
Even if I call [scrollView flashScrollIndicators] nothing happens.
Ideas?
Had the same problem and couldn't find the cause. The last answer gave the final hint: whenever I added new subviews I first removed all existing subviews from the scrollview (and apparently also the scroll indicators).
After checking in my loop, if the subview really was of the kind I wanted to be removed the scroll indicators showed up:
for (NSObject * subview in [[[scrollView subviews] copy] autorelease]) {
if ([subview isKindOfClass:[MySubView class]]) {
[(MySubView*)subview removeFromSuperview];
}
}
Update: changed code to Nikolai's suggestion
When I've dealt with this before, in my implementation of a grid, I would occasionally get some cells over the top of the scroll indicator. To fix this I am now inserting subviews at index 0 rather than adding them, which adds them to the top. So try something like this:
[scrollview insertSubview:subview atIndex:0];
For me, the horizontal indicator had mysteriously disappeared in my app on iOS 7. Later found out that for some strange reason, I had to enable both Shows Horizontal Indicator and Shows Vertical Indicator to make the horizontal one show up. If I set it to not show the vertical indicator, it would also not show horizontal indicator.
I fix this by adding this code after add new subview:
self.showsVerticalScrollIndicator = NO;
self.showsVerticalScrollIndicator = YES;
It will also happen (at least in the case of a UITableView) if the contentSize is too small for the table view to scroll. If you have enabled bouncing, then the tableview does not actually scroll and does not display the indicators therefore. Try fitting more content inside.
It can happen also if the parent of the scrollview is smaller horizontally than the scroll view itself :
The scroll bar is stuck to the right side of the ScrollView / TableView and this right side is not visible due to the parent bounds ( with a clipToBounds hidding it for instance).
I've seen this issue so I share it in case it can help.
Just check the width of your ScrollView's frame not to be bigger than the width of its parent view frame.
Two conditions,
If you are using a storyboard
If you are using a UITableView inside a UIViewController
Then, you should check your indicator insets are set to 0 (or any other number that is relevant to your autolayout):
Noticed this when the UIScrollView was a 48 px tall horizontal band, scrollable horizontally. Maybe Cocoa decides the area is too small for a scroll indicator...
I have a UITableViewController inside of a UINavigationController.
I want to have a UIView appear over the top of the table view but not susceptible to the scrolling of the table view.
I.e. if the table view is scrolled, the UIView should remain in the same position relative to the screen, rather than relative to the table view. It should appear anchored in a certain position.
What is the best way to achieve this?
EDIT: To clarify, the view should float transparently over the top of the table view.
Many thanks!
I also wanted to have a floating UIView over my tableView.
So, within my RootViewController (which is a UITableViewController), this worked for me
- (void)viewDidLoad {
/* mylabel is a UILabel set in this class */
[self.mylabel setUserInteractionEnabled:NO];
/* navigationController comes from higher up in the navigation chain */
[self.navigationController.view addSubview:self.mylabel];
}
Similar to what Peter said, create a UIView that will contain both the TableView and the subclassed UIView. Such as:
UIView *view = [[UIView alloc] initWithFrame:frame]; // Define frame as you like
[view addSubview:myTableView]; // This is the reference to your tableView
[view addSubview:myAnchoredView]; // This is the reference to your UIView "floating" subclass
You will also need to turn off user interaction for your floating view. I don't know if this will specifically pass the touches to the underlying UIView's or not though:
[myAnchoredView setUserInteractionEnabled:NO];
If this is blocking touches to your tableView, you may need to pass the reference to your tableView to the anchored view at initialization, then pass the touch events along. You can do this by overriding the touch response methods in UIResponder. (If there is a better way, someone please speak up.)
Do you mean the anchored view should appear transparent over the UITableView, or just above, i.e. anchored view uses top 20% of the available space, table view uses the rest?
In any case, create a UIView containing the anchored view and the table view. If you want the anchored view transparent over the table view, it's a bit tricky, because to scroll the table view, touches have to pass through the anchored view.
Add the surrounding view's view controller to the navigation controller instead of just the tableview.
I investigated how UIScrollView keeps its scrollIndicator above the UIScrollView's content and yet unmoving by examining a UIScrollView in the debugger.
The scrollIndicators are UIImageViews. And you can see they are direct descendants of the UIScrollView itself. You can also see that any scrolled content is also a direct descendent. So how is it that the scroll indicators don't move?
I tried updating the position of my static content constantly in - (void)scrollViewDidScroll:(UIScrollView *)scrollView this, surprisingly, works. I'm not sure if it is how UIScrollView itself does it, but without some private magic, it must be something like this.