I have a storyboard in which I have a view controller, (InfoViewController) in which I have an UIScrollView with some labels, uitextviews, etc. this is all created in IB, no code has been written at all. The only thing that is left for me to do is to set the content size, which I do as following:
-(void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
CGRect screenRect = [[UIScreen mainScreen] bounds];
[self.scrollView setContentSize:CGSizeMake(screenRect.size.width, 600)];
[self.scrollView setBackgroundColor:[UIColor greenColor]];
}
Whenever I make this view the entry point of my app, it works perfectly. I can see my view, the content size is set, the background color is being set to green.
Now it comes, I created another view controller, and this view controller is now my entry point of the app. I added a button in there, and on this button I did a "modal segue" to the earlier mentioned Info View Controller.
When I now run my app, I press this button, my Info View Controller shows up. The green background color is being set, but it's impossible to scroll. So the code is being executed (otherwise the background color couldn't been green, in the storyboard it's just plain white) but somehow whenever I use this "modal segue", the scroll functionality gets lost.
How can I fix this?
Try to insert a UIView into the scroll view...
Set the UIView with top, bottom, leading and trailing space to super view to 0.
Then insert everything into the UIView rather than into the ScrollView
Then modify the constraint height of the inner UIView instead of the contentsize of the scroll view, it works with iOS7
Related
I have a very basic view controller in an iMessage Extension. (Expanded view of course). I am aware that you can not have keyboard input int the Compact view...
The UITextView is constrained to the Element above it, and below it. It has a set height and width. The constraints are all in order, and are not broken.
All the options on the textview in interface builder have been left as DEFAULTS.
The following problems occur with the UITextView:
When I begin editing, the cursor is barely visible. (on the bottom of the field, half way cut off vertically).
Typing the first letter brings the cursor to the vertical centre of the Text View.
Putting a new line and then a character, puts the cursor back down again.
Then typing subsequent characters after that will bring the cursor to the Vertical Centre again. And every other character scrolls the whole text view to the bottom again. So you get this weird bounce up and down behaviour with every key stroke.
The Scroll Bar visual hint on the right side does not reflect the proper height of the text view, when I scroll. (The scroll bar only goes down half way - of the text view's height.)
I expect the UITextView to work like this by default:
Cursor should go to the TOP of the text view, when activated and editing.
Text View should not jump when typing keys after a new line.
Vertical Scroll Bar indicator should show the full range of the text field, and not half of it.
So, obviously the internal Scroll View inside the Text View has a problem figuring out the sizes of things.
Does anyone know, if this is an iMessage specific issue, or whether anyone has had this problem outside of iMessage as well, and how to fix?
My IB constraints (The second view down is the text view):
Video Demo of the problem:
https://youtu.be/1bkvHnkXLWM
UPDATE: I am using Child View Controllers to embed my View Controller inside the Root Controller. I have tried a blank Hello World application, and the UITextView works normally by default. So the issue, therefore is related to the way i'm embedding a Child View Controller.
This is the code I'm using to embed my Child View Controller:
- (void)showViewController:(UIViewController*)vcToShow isPop:(BOOL)isPop
{
NSLog(#"Presenting Controller: %#", vcToShow);
[self.activeVC willMoveToParentViewController:nil];
[self addChildViewController:vcToShow];
vcToShow.view.translatesAutoresizingMaskIntoConstraints = NO;
vcToShow.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self.rootView addControls:#[vcToShow.view]
align:VerticalAlignStretchToFullHeight];
UIViewController* currentVC = self.activeVC;
self.activeVC = vcToShow;
vcToShow.view.alpha = 0.0f;
[self transitionFromViewController:currentVC
toViewController:vcToShow
duration:0.3
options:UIViewAnimationOptionTransitionNone
animations:^{
vcToShow.view.alpha = 1.0f;
}
completion:^(BOOL finished) {
[currentVC removeFromParentViewController];
[vcToShow didMoveToParentViewController:self];
[self updateScreenState];
if (isPop) {
[self removeReferenceToController:currentVC];
}
}];
}
I have a solution.
Instead of using Interface Builder to place my UITextView, I used my own programmatic constraint generation method to create and place the UITextView, only after ViewDidAppear.
My suspicion is that at the time Interface builder rendered the Child VC's view, it did not have everything populated that the UITextView's internal scroll view needed. So the scroll view got initialized with wrong dimension values, and therefore would glitch out on anything scrolling related. After doing everything in viewDidAppear programmatically (in the Child VC), the text view now scrolls properly, and the cursor is always at the beginning, working as expected.
The update code:
Took UITextView out of interface builder completely.
Added it programmatically (called from viewDidAppear):
self.textView = [[UITextView alloc] init];
self.textView.translatesAutoresizingMaskIntoConstraints = NO;
CGFloat topPadding = self.instructionLabel.frame.origin.y + self.instructionLabel.frame.size.height + TEXT_VIEW_TOP_PADDING;
// This custom method generates Visual Constraint format for me
// so i don't have to write manual individual constraint syntax.
[self.rootView addControls:#[self.textView]
align:VerticalAlignTop
withHeight:TEXT_VIEW_HEIGHT
verticalPadding: 0
horizontalPadding: 20
topPadding: topPadding];
I have a UIViewController that displays a form with several text fields. In order to prevent the text fields from getting blocked by the keyboard, I resize the controller's view when the keyboard appears and disappears.
However, when the keyboard is up, the user presses the home button, and then returns to the app, the controller's view will be resized again to the size it was before the keyboard was up and the keyboard will still be showing.
What's causing my controller's view to be resized on return from background, and how can I prevent it?
Maybe you need to nest a UIView，for example
_backgroundView = [UIView new];
_backgroundView.backgroundColor = [UIColor whiteColor];
_backgroundView.frame = CGRectZero;
[self.view addSubview:_backgroundView];
[_backgroundView mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.right.top.mas_equalTo(self.view);
make.height.mas_equalTo(self.view.mas_height);
}];
then you need add your custom UIView to this backgroundView.
as you said，UIViewController's view will be resized after return from background. so you can nest a UIView of the same size as self.view，and add your custom UIView to this UIView.
In order to prevent the text fields from getting blocked by the keyboard, you can resize this backgroundView when the keyboard appears and disappears. and this time when you click the home button to enter the background or return from background，self.view won't be resized and backgroundView won't be resized too.
Although it is a bit of a hassle, this will solve your problem and will not affect the user experience anymore. And if you have a better solution, please let me know
It sounds like you are setting the frame and not using autolayout. When the view reappears viewDidLayoutSubviews gets called and your frame gets recalculated obliterating your previous change. You can either:
1) Move your frame to viewDidLayoutSubviews and change its size only if the keyboard is showing.
2) Use autolayout and simply pull up your bottom constraint .constant by an amount equal to your keyboard height.
In both cases you should call layoutIfNeeded to trigger autolayout/viewDidLayoutSubviews when the keyboard appears/disappears. This behavior is a good example of why you should not manipulate your frames outside of viewDidLayoutSubviews except for transitory animations.
I have a view with some UI components and a button on it, upon touch of a button I want to show a half view with some textfields on it overlapping the initial view, the initial view should be visible partly , the overlapping view will cover only half screen from bottom. Is this possible ?
I don't have any code as I am unable to figure out what it needs to be done, as we show any view it covers the entire screen.
Thanks
there are several ways you can do this, here are two:
1) add a popover controller that gets displayed on your button press:
here's some apple documentation on popovers: https://developer.apple.com/Library/ios/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/Popovers.html
2) add the new view as a subview to your UIViewController
PROGRAMICALLY:
in the viewDidLoad function you can do the following to initialize the halfScreenView
GLfloat topOffset = self.view.frame.size.height/2;
UIView halfScreenView = [[UIView alloc] initWithFrame: CGRectMake(0, topOffset , [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height - topOffset)
[self.view addSubview:halfScreenView];
-more logic might be needed if you support Landscape orientation, you can always re-assign the location of the view with halfScreenView.frame.origin and halfScreenView.frame.size
-initially you can have this view be hidden
halfScreenView.hidden = YES;
-when you click the button it will show the overlaying view:
halfScreenView.hidden = NO;
USING STORYBOARD:
you can also set up your overlaying view in the storyboard if you have one
-drag a UIView into your UIViewController and set it up where you want it to be located
-initialize the view to be hidden by checking the hidden box in the attribute inspector
-add the view as a property to your view
-manage when to show this view with self.halfScreenView.hidden
-this technique allows you to customize what is inside the new view within the storyboard which is nice
FOR BOTH:
-be careful with layers, you don't want your view to show up behind the one you already present. In the storyboard the last thing inserted goes on top. With in the code you can always access/change the views z position with halfScreenView.layer.zPosition (higher z values are on top)
First create a new class subclassing UIViewController called SecondView (or whatever you want), then design the UI the way you want (in its .xib file)
Then go to your main view controller's file and make an IBAction for that button.
In that method, write:
SecondView* second = [[SecondView alloc] initWithFrame:CGRectMake(0, [[UIScreen mainScreen] bounds].size.height/2, height, width);
[self.view addSubview:second.view];
This will add it to the bottom half of the screen. Put your own parameters for its height and width. When you want to dismiss the view, you can do this inside your SecondView class
[self.view removeFromSuperview];
You can deal with the textFields from within the SecondView class and have them communicate with your other view by doing the following in SecondView.h
#property IBOutlet UITextField* textField;
Hope this helps!
Yes, assuming you are using Interface Builder, go ahead and build the overlapping view and hook up all of the IBOutlets and IBActions. Say this view is called myView. Set myView.hidden = YES and myView.enabled = NO. This hides and disables myView so that it isn't even there from the user's perspective. In the appropriate button's IBAction, change the hidden and enabled properties to YES. That will make the view visible and active again.
I get a weird interface bug with my UIScrollView and I cant figure out how to solve it. I only wrote one line of code (shown below) and it is a blank project's setup easily reproducible!
Setting:
I have a UIScrollView that contains a UISegmentedControl (since the segments of
the control are loaded dynamically, it could exceed the width of the screen and the scrollView is supposed to scroll the segmentedControl horizontally, the height of the scrollview is the same as the UISegmentedControl's).
The ViewController that contains this is embedded in a tabBar (or navigation bar, which also shows the bug). The whole thing is using Auto-Layout.
Bug:
When I scroll the SegmentedControl some degree to the right and then switch the viewController by clicking the other tab on the tabBarController, the content-offset of the segmented control gets weirdly shifted when switching back to the initial viewcontroller. When I try to scroll to the leftmost part of the scrollview it won't let me. When switching the tabs a couple of times, it gets fixed again and I can do this over.
What I did (can you reproduce this?):
Create a blank single-view ios project
Embed the already given viewController in a tabbarcontroller.
Put a scrollView on the upper portion of the view that fits the screen from left to right.
Put a UISegmentedControl on the topleft corner of the scrollview and drag the scrollview to fit the segmented controls height height
Change the Segmented control's width a bit so xcode adds a width-constraint. in the segmented control's width constraint change the width constraint's relation to "greater than or equal"
create an outlet to the segmented control
in viewDidload add this code
[self.segmentedControl insertSegmentWithTitle:#"A really long title so it you have to scroll to see it" atIndex: 0 animated: NO];
Create a blank viewcontroller and add it as a second viewController for the tabbarController.
This is how my storyboard looks like:
Now run the project, scroll the segmented control to it's right end as far as it goes. Switch the tab and switch back and please tell me how your scrollview now behaves - and WHY.
My guess would be it has something to do with Auto Layout maybe? Can't figure out what though.
I tried fixing this by setting the scrollView's contentSize in viewDidAppear or changing the content offset of the scrollView in viewDidAppear or changing frames, combination of those and what not....
Extra question:
Is it no longer neccessary to set the scrollViews contentSize property? Why does it scroll the content automatically?
After googeling I found the answer in another StackOverflow question.
What you need to do is save the scrollview.contentOffset on viewWillDisappear,
set it to CGPointZero on viewDidDisappear and set it back to the saved state on viewDidLayoutSubviews:
-(void) viewWillDisappear: (BOOL) animated {
self.lastContentOffset = self.scrollView.contentOffset;
[super viewWillDisappear: animated];
}
-(void) viewDidDisappear:(BOOL)animated {
[super viewDidDisappear: animated];
self.scrollView.contentOffset = CGPointZero;
}
- (void)viewDidLayoutSubviews {
[super viewDidlayoutSubviews];
self.scrollView.contentOffset = self.lastContentOffset;
}
I don't know if this makes sense at all. I have UIScrollView from interface builder hooked it up as an outlet on top of my UIScrollView I have a UIImage view which holds an image called Scroll Background it is an extra half in screen real estate - my app is landscape and the image is an about half the screen taller. The image is hooked up as an outlet too. I have a button on a toolbar that brings up the keyboard when the button is pressed I'd like to programmatically scroll to the bottom of the UIImage view and when it is resigned I'd like to programmatically scroll to the top. I don't want the user to be able to scroll just for the app to scroll programmatically.
I can't seem to get this method to work and I'm not sure why :/
- (void)scrollRectToVisible:(CGRect)rect animated:(BOOL)animated
scrollRectToVisible:animated: is a non-intuative method to use in my opinion. In order to accomplish what you are after you should be able to set userInteractionEnabled to NO on the UIScrollView that will prevent users from scrolling.
Then in order to scroll the view programmatically you can call scrollRectToVisible but you need to give it a CGRect that is representative of the area you want to show. So in your case to scroll to the top:
CGRect visibleFrame = CGRectMake(0, 0, CGRectGetWidth(self.view.bounds) , CGRectGetHeight(self.view.bounds));
[self.myScrollView scrollRectToVisible:visibleFrame animated:YES];
Hope this helps!