I have a UIScrollView with a View inside of it. Inside of that view is a bunch of buttons, labels, etc that fit in the View when in Portrait mode...When the iPad is rotated, I want the scrollView to kick in so the user can scroll to the bottom of the view. The app runs, but when I rotate it, the scroller never works...I believe I've wired everything up correctly and I have this code in the viewDidLoad event:
[scrollview addSubview: masterView];
scrollView.contentSize = [masterView sizeThatFits:CGSizeZero];
Is there something else I am missing? Do I need to modify the size when the iPad rotates?
thanks
There may be a problem with the content size of the UIScrollView. Without the contentSize being set larger than the actual scrollView size, scroll bars won't be shown.
You can code this in with something like this:
[scrollView setContentSize:CGSizeMake(2000,2000)];
And then changing the content size to the actual content size of what you are putting in the UIScrollView (scrollView).
If you look at the results of [masterView sizeThatFits:CGSizeZero] (e.g. NSLog or set a breakpoint in your debugger, I think you will find that it's not what you expected it to be. You might find that masterView has autoResize parameters set (which is common for a view that covers the entire screen), which means that it might, itself, be getting resized too short to fit all of its controls and scrollView is simply grabbing this shortened value itself. Take a look at that CGSize and the problem will be obvious.
I faced similar situation but my case was iPhone.
Remember that content should be larger than scroll for scrollView to kick in.
"Why would you want to go down if everything is visible in front of you ?"
use the following code:
[scrollView setContentSize:CGSizeMake(intValue, intValue)];
intValue: Integer values setting width and height of scroll.
Even if it doesn't works, don't worry there are loads of other options to figure out the solution:
1. NSLog
2. Breakpoints
3. Put up errors you are getting from console on stackoverflow
Related
I have some modal controllers that are UIViews and are not scrolling.
Reading on SO, the apple docs and elsewhere, it seems there are three approaches to fixing this:
Multiselect all the elements within the view and then go
editor-embedin-UIScrollview.
change the view to a scrollview in the identity inspector and then
add the following line to viewdidload:
[(UIScrollView *)self.view setContentSize:CGSizeMake(320, 2000)];
Copy elements to clipboard, delete the uiview, add a new scrollview
and copy the elements into the scrollview. Warning - this destroys
the positioning of the elements although it does preserve their
outlet properties.
However, I have tried all of these and the scrollview still does not scroll.
Is there any other step I am missing?
Thanks in advance for any suggestions.
Edit:
Getting scrollviews to work is not easy and there is much conflicting advice on the web.
I finally got this to work by setting the content size in a separate method as opposed to viewdidload.
(void)viewDidLayoutSubviews {
self.MainScroll.contentSize = CGSizeMake(320, 1800);
}
Thanks as well to Evo for advice on setting all the vertical dimensions correctly and using freeform in the VC size inspector as it won't work if you don't carefully set these.
If you have EVER enabled autolayout, even if it's disabled now, you need to:
Select the view controller you plan on scrolling
At the bottom right of the storyboard view, click the third button (far right) and then "Reset to Suggested Constraints"
Make sure that all the elements in the scrollview are embedded in the desired positions.
If you are not using autolayout:
Check that the Size of the view controller is set to (320, 2000), or whatever you want.
In the Simulated Metrics of the view controller, you can set the size type to Freeform.
Then in the tab to the right of Simulated Metrics, you can set the width and height to the desired values.
Please comment any concerns
I have a UIScrollView which continually adds extra space at the bottom of its scroll area on iOS 7. If I rotate the device, the problem fixes itself, however, before rotating after first navigating to the view controller, the extra space always appears. I've included an image below:
What I've tried:
Set automaticallyAdjustScrollViewInsets to NO
Checked contentSize, contentOffset and contentInset. All appear fine.
I'm not sure what else to try to solve this issue, and would greatly appreciate any help or direction here!
Edit: As another layer of complexity to this issue... I call a method, updateScrollViewContentSize in my viewDidAppear: method. When I rotate, and it somehow fixes itself, this same method is called. So my contentSize is being set when my view appears and when I rotate.
To make things worse, the content size is always set to 638... Whether there is extra space or not. But, for some reason, the scrollView ignores this until we rotate.
Here is the method to update the contentSize:
- (void)updateScrollViewContentSize {
[self.scrollView setContentSize:CGSizeMake(self.scrollView.frame.size.width, (self.feedbackFooterView.frame.origin.y + self.feedbackFooterView.frame.size.height + 20))];
}
Hi I have set in my storyboard a UIScrollView (of the same size of the view) and ctrl-dragged it in my code.
Now I have created a button programmatically using a simple algorithm of mine.
I then tried to
println(button.frame.origin.y)
which printed 1700.
Then I tried
println(button.frame.height)
which printed 142.2 (also coming from the algorithm). So the heigh I would like to reach while scrolling is 1700 + 142.2 = 1842.2
So i tried to hardcode the content size in this way
self.scrollView.contentSize = CGSize(width:self.view.bounds.size.width, height:2000)
But when I run the app I can scroll no more than the middle of the button, which is in numbers
1700 + 142.2/2 = 1771.1
Why the heck is that?
I did all this to try to understand how this UIScrollView works but I can't figure it out.
EDIT
Added a screenshot.
Inside the bubbles there is the button.frame.origin.y value. That's the max I can scroll leaving the screen untouched.
This is probably to do with scroll view insets - a mechanism where the edges of the content always appear under the navigation and toolbar.
You either need to manually account for this by reading the contentInset property of the scroll view, or using interface builder.
Scroll view Reference:
https://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/UIScrollView_pg/CreatingBasicScrollViews/CreatingBasicScrollViews.html
I was using a xib to do some simple view layouts and noticed that the size of my subviews was incorrect in relation to the size of the view itself.
I decided the last time I tried to ask this question I may have already had too complicated of a product for people to fully understand what I was asking.
Here is a simple view:
It is exactly as I would like it to be position and exactly how I would have expected to lay itself out as shown here:
If you notice at the bottom there, I did a log of the size of the views. The log is as follows in my viewDidLoad lifecycle method.
NSLog(#"%f, %f", [[UIScreen mainScreen] bounds].size.width, self.blockView.bounds.size.width);
Why is it that the view width is in no way close to the actual width reported my the application's view size? I am trying to cast a shadow under my subview but since programmatically it thinks the view is much wider, this wont work. Also positioning any subviews programmatically in the purple view shown there will not work either since the frame does not match the expect frame.
PLEASE HELP.
thank you.
EDIT: LACK OF SLEEP LEADS TO FORGETTING LIFE CYCLES....
You should log the view width in viewDidAppear.
viewDidLoad is called after the view controller has loaded its view
hierarchy into memory.
By the time viewDidLoad is called, auto layout hasn't finished calculating your view position according to the constraints of the view.
I have a UIView with a UIImageView at the very top, a UILabel below it, a UIButton below that, and a UISegmentedControl that determines what determines what embedded UIview to display at the bottom (which also a choice to not show any at all).
I've run into the problem where I've set up all of my constraints in the interface builder, and everything seems to be fine when I switch between screen sizes in the storyboard. However when I actually run the project on a device or emulated, the UIimage at the top is briefly stretched before "snapping" into a size the fits the constraints. Also, it seems as if the label disappears for a brief second and reappears after the image has snapped into a size. After the "snap" has occurred, everything is in place and there are no problems.
This snapping occurs both when testing on a 4 and 3.5 inch display. I find this odd because I've designed the UI for the 4inch screen perfectly.
Does anyone know why this is happening?
Edit
Here's whats the constraints look like in IB.
This is potentially due to adjustments that you might be making to your UI elements (or constraints) from the view controller in code. For example, if you are programmatically setting a different UIImage into your UIImageView, and this code is happening too late in the view lifecycle (for example, in viewDidAppear) after a layout pass has already calculated view positions and sizes, then you will see a visible snap as views take on new positions based on the new intrinsic content size of the image view.
This could be caused by other adjustments such as injecting a localized string into a UILabel in code, which causes the label to have a smaller or larger intrinsic content size, which in turn affects the layout based on your constraints.
If you are making adjustments to your UI in code, make sure they are happening in viewDidLoad or viewWillAppear: so that they occur before the view's initial layout pass (and the view's animation onscreen).
If you're still seeing issues, you can try explicitly forcing an immediate layout pass to occur on the view controller's view at the end of viewWillAppear: by doing the following:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.view setNeedsLayout];
[self.view layoutIfNeeded]; // forces an immediate layout pass
}
Spacing between the UIElements might be the problem . Specially when using Pickers
Got it, You have applied constraint for Picker to adjust along with segmented control. So when app runs on 4 inch screen , picker automatically fits properly, but for 3.5 Inch picker always starts from bottom of the screen and picker will push segmented control upwards and hence segmented control will push rest control automatically.
Remove picker and segmented control constraint.