I am having 15 textFields which are on the same view.
Now as the keyboard comes up, I resize my scroll view in order to make the textFields which are on the lower portion of the view to be visible.
I observed that switching from one textField to another brings the scrollView to its original frame.
How can i avoid my scrollview's frame from resetting everytime I resign the first responder from textField?
// Here I am resetting the scrollView size so the textField do not hide behind the keyboard.
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
[scroll setFrame:CGRectMake(503, 123, 515, 275)];
[scroll setContentSize:CGSizeMake(515, 550)];
}
// Here I am resizing the scrollView so after returning the keyboard the scrollView gets its original hight
- (void)textFieldDidEndEditing:(UITextField *)textField
{
[scroll setFrame:CGRectMake(503, 123, 515, 570)];
[scroll setContentSize:CGSizeMake(515, 560)];
}
Why do you change the content size for the scrollView each time?
[scroll setContentSize:CGSizeMake(515, 560)];
It would be better to have a fixed contentSize for it and change the contentOffset of the scrollView based on the textField
I think you’re confused about how contentSize works -- if the contents of your scrollview are not ever changing (the text fields are not removed when you show the keyboard), then you shouldn’t change the contentSize. Setting the frame, as you are doing, should be sufficient.
Related
My UIScrollView is a ~4500px horizontal view that the user needs to scroll horizontally through to view the content.
I have set it up as follows:
- (void)viewDidLoad
{
[super viewDidLoad];
sview.frame = CGRectMake(0, 0, 568, 320);
sview.contentSize = CGSizeMake(4500, 320);
[sview setScrollEnabled:YES];
}
Yet the scroll view does nothing. Is there something obvious I missed? i've tried literally every tutorial on the web.
I got similar issue. I did following modifications and the scrollView started scrolling for me:
Select to check the 'Bounce Horizontally' property for UIScrollView
in xib.
Move the code following code to viewDidAppear instead of
viewDidLoad:
-(void) viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
sview.frame = CGRectMake(0, 0, 568, 320);
sview.contentSize = CGSizeMake(4500, 320);
[sview setScrollEnabled:YES];
}
I think this should help you.
I've explained it here, but there are so many answers to this problem that suggests turning off Auto Layout. That fixes the problem but that's not really the correct solution. Here's my answer:
Turning Auto Layout works, but that's not the solution. If you really need Auto Layout, then use it, if you don't need it, turn it off. But that is not the correct fix for this solution.
UIScrollView works differently with other views in Auto Layout. Here is Apple's release note on Auto Layout, I've copied the interesting bit:
Here are some notes regarding Auto Layout support for UIScrollView:
In general, Auto Layout considers the top, left, bottom, and right edges of a view to be the visible edges. That is, if you pin a view to
the left edge of its superview, you’re really pinning it to the
minimum x-value of the superview’s bounds. Changing the bounds origin
of the superview does not change the position of the view.
The UIScrollView class scrolls its content by changing the origin of its bounds. To make this work with Auto Layout, the top, left, bottom,
and right edges within a scroll view now mean the edges of its content
view.
The constraints on the subviews of the scroll view must result in a size to fill, which is then interpreted as the content size of the
scroll view. (This should not be confused with the
intrinsicContentSize method used for Auto Layout.) To size the scroll
view’s frame with Auto Layout, constraints must either be explicit
regarding the width and height of the scroll view, or the edges of the
scroll view must be tied to views outside of its subtree.
Note that you can make a subview of the scroll view appear to float (not scroll) over the other scrolling content by creating constraints
between the view and a view outside the scroll view’s subtree, such as
the scroll view’s superview.
Apple then goes on to show example of how to correctly use UIScrollView with Auto Layout.
As a general rule, one of the easiest fix is to create a constraint between the element to the bottom of the UIScrollView. So in the element that you want to be at the bottom of the UIScrollView, create this bottom space constraint:
Once again, if you do not want to use Auto Layout, then turn it off. You can then set the contentSize the usual way. But what you should understand is that this is an intended behaviour of Auto Layout.
First of all you have to add some content to UIScrollSiew as subview for scrolling,without content on UIScrollView how can you scroll?. Here is what i did,just add UIImageView to UIScrollView as subview of size same as size of UIScrollView...
In viewDidLoad method try the following code..
-(void)viewDidLoad
{
UIScrollView *scroll=[[UIScrollView alloc] init];
scroll.frame=CGRectMake(0, 0, 320, 460);
UIImageView *imageView=[[UIImageView alloc] init];
imageView.frame=CGRectMake(0, 0, 320,460);
imageView.image=[UIImage imageNamed:#"chiranjeevi.jpeg"];
scroll.contentSize = CGSizeMake(4500, 460);
[scroll setScrollEnabled:YES];
[scroll addSubview:imageView];
[self.view addSubview:scroll];
}
I tested this code it works well.I hope this code will be helpful to you..
I assume you are adding UISrollingView in your Xib file. This will work for you.
sview.delegate = self;
sview.backgroundColor=[UIColor clearColor];
[sview setCanCancelContentTouches:NO];
sview.indicatorStyle = UIScrollViewIndicatorStyleWhite;
sview.clipsToBounds = YES;
sview.scrollEnabled = YES;
sview.contentSize = CGSizeMake(320,570);
CGPoint topOffset = CGPointMake(0,0);
[sview setContentOffset:topOffset animated:YES];
Also, make sure to give IBOutlet connection in your Xib file.
I also faced the same issue.I added the scroll view in xib.I also added some subviews to this scroll view. The scroll view would stop scrolling after I added the subviews. The solution for this problem was in the xib for the view in file inspector Use Autolayout was checked. I unchecked it and the scroll view scrolled after adding the subviews.
The solution was uncheking the Use Autolayout in file inspector in xib.
I have a UIToolbar set to the inputAccessoryView of a UITextView. This shows the toolbar on top of the keyboard, when editing. I have, however, encountered a problem when rotating the device: the toolbar should become a little less heigh (32 pixels vs 44). When I just update the height of the toolbar, I get a little white space between the toolbar and the keyboard:
So I used -didRotateFromInterfaceOrientation: to also update the origin, and then it works when rotating from portrait to landscape. When rotating back up, however, the toolbar is 12 pixel too low and overlapping the keyboard:
By then, the origin is (0,0) again and setting a negative value didn't help. Any suggestions of how to make it work so that the toolbar changes its size and never overlaps?
I fixed it by calling [textView resignFirstResponder] in -willRotateToInterfaceOrientation:duration: and [textView becomeFirstResponder] in -didRotateFromInterfaceOrientation:. The system seems to adjust the frame properly.
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
didShowKeyboard = [self.textView isFirstResponder];
[self.textView resignFirstResponder];
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
CGRect toolbarFrame = [self.navigationController.toolbar bounds];
self.keyboardToolbar.frame = toolbarFrame;
if (didShowKeyboard)
[self.textView becomeFirstResponder];
}
Instead of Calculating the Origins and sizes you can use Autosizing to render the Controls during rotation.
See this tutorial http://www.bogotobogo.com/XcodeSDK-Chapter4.html
I think this can give you a hint.
I'm working on a browser app, and I have an address bar on top the UIWebView. On MobileSafari if you scroll down, the address bar starts to move to the top, out of the screen, and the UIWebView doesn't scroll. Only when the address bar disappears completely, it starts to scroll. I would like to have this effect in my app as well.
What's the best way to implement this?
Thanks
The only way to implement this requires iOS 5.
In iOS 5, UIWebView has an UIScrollView subview.
And use the following code:
Set a area for the address bar:
[[myWebView scrollView] setContentInset:UIEdgeInsetsMake(64, 0, 0, 0)];
Move the address bar using the scrollview delegate:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
if(scrollView.contentOffset.y>=-64&&scrollView.contentOffset.y<30)
{
topBar.frame=CGRectMake(0,-44-scrollView.contentOffset.y, 320, 44);
}
else if(scrollView.contentOffset.y<-64)
topBar.frame=CGRectMake(0,20, 320, 44);//Lock the position
}
There is a way, but I am not sure if it is a bit too hacky. First search for the scrollview within the webview, then alter the contentInset and finally add the searchbar(for example) to the scrollview. The following code is just an example, I did not set any frames correctly and 40 is just a made up height for the searchbar. I am not sure if this will work in every iOS Version.
UIWebView * myWebView = [[UIWebView alloc] init]
UISearchBar * mySearchBar = [[UISearchBar alloc] init];
for (NSObject * aSubView in [myWebView subviews]) {
if ([aSubView isKindOfClass:[UIScrollView class]]) {
UIScrollView * theScrollView = (UIScrollView *)aSubView;
theScrollView.contentInset = UIEdgeInsetsMake(40, 0, 0, 0);
[theScrollView addSubview:mySearchBar];
}
}
PeakJi's solution works but is a bit laggy. A better solution would be adding an observer to the UIScrollView's content offset, something like
[scrollview addObserver:self forKeyPath:#"contentOffset"
options:NSKeyValueObservingOptionNew context:nil];
You can find more document on NSKeyValueObserving protocol at
https://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Protocols/NSKeyValueObserving_Protocol/Reference/Reference.html
Come to think of it, it is simply a scrolling view with an address bar stuck on the top, and both the web view and the bar always move together. Now, lets say you create a scroll view and add two subviews, the address bar and the web view (one below the other). It is to be noted that the height of the web view is determined and fixed after the page has been loaded (in webViewDidFinishLoad:).
Hence, it is simply a scrolling view whose contentSize is equal to the height of the bar + the height of the web view. Now, by default the web view allows scrolling, as it has a scroll view as a subview. As only the outer scroll view should be scrolling, it is required that the web view's scrolling be turned off. For that, fetch the first subview (that's the scroll view) and disable its scrolling using:
(UIScrollView*)[myWebView.subviews objectAtIndex:0].scrollEnabled = NO;
I use Textview for insert message text but when i focus in textview second time after insert some text then already inserted text shifted upside. so text cut in the TextView.
Any solution for this problem?
UITextView the subclass of UIScrollView. So you can discard scroll to top like this:
((UIScrollView*)someTextView).delegate = self; // or some other UIScrollViewDelegate
and implement this method:
-(void) scrollViewDidScroll:(UIScrollView*) scrollView {
scrollView.contentOffset = CGPointMake(0, 0);
}
But if you do need scrolling during edit, you can add some boolean flags to distinguish the situations when user is scrolling and when the scrolling is automatic.
I have the UIScrollView with pagingEnabled set to YES, and programmatically scroll its content to bottom:
CGPoint contentOffset = scrollView.contentOffset;
contentOffset.y = scrollView.contentSize.height - scrollView.frame.size.height;
[scrollView setContentOffset:contentOffset animated:YES];
it scrolls successfully, but after that, on single tap its content scrolls up to offset that it has just before it scrolls down. That happens only when I programmaticaly scroll scrollView's content to bottom and then tap. When I scroll to any other offset and then tap, nothing is happened.
That's definitely not what I'd like to get. How that should be fixed?
Much thanks in advance!
Timur.
This small hack prevents the UIScrollView from scrolling when tapped. Looks like this is happening when the scroll view has paging enabled.
In your UIScrollView delegate add this method:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
scrollView.pagingEnabled = self.scrollView.contentOffset.x < (self.scrollView.contentSize.width - self.scrollView.frame.size.width);
}
This disables the paging when the scroll view reaches the right end in horizontal scrolling (my use case, you can adapt it to other directions easily).
I just figured out what causes this problem, and how to avoid it. If you having pagingEnabled set to YES on a scroll view, you must set the contentOffset to be a multiple of the scroll view's visible size (i.e. you should be on a paging boundary).
Concrete example:
If your scroll view was (say) 460 pixels high with a content area of 920, you would need to set the content offset to EITHER 0 or 460 if you want to avoid the "scroll to beginning on tap" problem.
As a bonus, the end result will probably look better since your scroll view will be aligned with the paging boundaries. :)
The following workaround did help (assume that one extends UIScrollView with a category, so 'self' refers to its instance):
-(BOOL) scrolledToBottom
{
return (self.contentSize.height <= self.frame.size.height) ||
(self.contentOffset.y == self.contentSize.height - self.frame.size.height);
}
Then, one should sometimes turn pagingEnabled off, just at the position where scroll view reaches its bottom. In the delegate (pagingEnabled is initialy on of course, since the problem occurs only when it is enabled):
-(void) scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.pagingEnabled == YES)
{
if ([scrollView scrolledToBottom] == YES)
scrollView.pagingEnabled = NO;
}
else
{
if ([scrollView scrolledToBottom] == NO)
scrollView.pagingEnabled = YES;
}
}
This seems to be a bug:
UIScrollView doesn't remember the position
I have tested this on iOS 4.2 (Simulator) and the issue remains.
When scrolling a ScrollView I would suggest using
[scrollView scrollRectToVisible:CGRectMake(0,0,1,1) animated:YES];
Where the rect is the position you're after. (In this case the rect would be the top of the scrollview).
Changing the content offset is not the correct way of scrolling a scrollview.