I have a UITextView that has a lot of content (e.g. credit view), and I want to create an automatic scrolling view for it (something like the credits page for Firefox)
where it automatically scrolls the names
I have tried the following, but it is not smooth, and I also require it to happen automatically when user goes to that view
CGPoint scrollPoint = textView.contentOffset;
scrollPoint.y= scrollPoint.y+10;
[textView setContentOffset:scrollPoint animated:YES];
Any guidance?
Since UITextView is a subclass of UIScrollView, you can use its scrollRectToVisible:animated: method to scroll with animation to any point you wish.
The PageControl sample code demonstrates its use (although it's scrolling horizontally).
So far I have done this, but still it is not smooth...
Any suggestions?
- (void)viewDidLoad {
[super viewDidLoad];
[self run];
}
-(void)run{
CGRect Frame1 = CGRectMake(5.0,5.0, 100.0,400.0);
CGPoint scrollPoint = textView.contentOffset;
scrollPoint.y= scrollPoint.y+100;
[textView setContentOffset:scrollPoint animated:YES];
[textView scrollRectToVisible:Frame1 animated:YES];
NSTimer *time;
time=[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:#selector(run) userInfo:nil repeats:YES];
}
Neither scrollRectToVisible: animated: nor setContentOffset: animated: have a property to control the speed or duration in which the animation occurs, so both will scroll fairly quickly to the destination point. They aren't good solutions for something like credits, which should scroll slowly.
Using UIView animateWithDuration: and then passing a contentOffset in the animation block is probably the best way to do this. However, there is a bug that clips text at the top if the length of the text is too long (even in iOS 10.0 SDK). There are two viable work-arounds for this bug discussed here:
UIView.animateWithDuration on UITextfield's contentoffset: It clips the text (Swift)
Related
I have seen this question being addressed several times here at SO, e.g Problem with UIScrollView Content Offset, but I´m still not able to solve it.
My iphone app is basically a tab bar controller with navigation bar. I have a tableview controller made programmatically and a DetailViewController that slides in when I tap a cell in my tableview controller.
The DetailViewController is made in IB and has the following hierarchy:
top view => UIScrollView => UIView => UIImage and a UITextField.
My goal is to be able to scroll the image and text field and this works well. The problem is that my UIScrollView always gets positioned at the bottom instead at the top.
After recommendations her at SO, I have made my UIScrollView same size as the top view and instead made the UIView with the max height (1500) of my variable contents.
In ViewDidLoad I set the contentSize for the UIScrollView (as this is not accessible from IB):
- (void)viewDidLoad {
[scrollView setContentSize:CGSizeMake(320, 1500)];
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
NSLog(#"viewDidLoad: contentOffset y: %f",[scrollView contentOffset].y);
}
Specifically setting the contentOffset, I would expect my scrollView to always end up at the top. Instead it always go to the bottom. It looks to me that there is some autoscrolling beyond my control taking place after this method.
My read back of the contentOffset looks OK. It looks to me that there may be some timing related issues as the scrolling result may vary whether animation is YES or NO.
A ugly workaround I have found is by using this delegate method:
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrView {
NSLog(#"Prog. scrolling ended");
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
}
This brings my scrollview to top, but makes it bounce down and up like a yo-yo
Another clue might be that although my instance variables for the IBOutlet are set before I push the view controller, the first time comes up with empty image and textfield:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (!detailViewController) {
detailViewController = [[DayDetailViewController alloc] init];
}
// Pass dictionary for the selected event to next controller
NSDictionary *dict = [eventsDay objectAtIndex:[indexPath row]];
// This method sets values for the image and textfield outlets
[detailViewController setEventDictionary:dict];
// Push it onto the top of the navigation controller´s stack.
[[self navigationController] pushViewController:detailViewController animated:NO];
}
If I set animation to YES, and switch the order of the IBOutlet setting and pushViewController, I can avoid the emptiness upon initialization. Why?
Any help with these matters are highly appreciated, as this is really driving me nuts!
Inspired of Ponchotg´s description of a programmatically approach, I decided to skip interface builder. The result was in some way disappointing: The same problem, with the scrollview ending up in unpredictable positions (mostly at bottom), persisted.
However, I noticed that the scroll offset error was much smaller. I think this is related to the now dynamic (and generally smaller) value of ContentOffset. After some blind experimenting I ended up setting
[textView setScrollEnabled:YES];
This was previously set to NO, as the UITextView is placed inside the scrollview, which should take care of the scrolling. (In my initial question, I have erroneously said it was a UITextField, that was wrong)
With this change my problem disappeared, I was simply not able to get into the situation with scrollview appearing at bottom anymore in the simulator! (At my 3G device I have seen a slight offset appear very seldom, but this is easily fixed with scrollViewDidEndScrollingAnimation delegate described previously ).
I consider this as solved now, but would appreciate if anyone understand why this little detail messes up things?
OK! i have a question before i can give a correct answer.
Why are you using a UIView inside the Scrollview?
You can always only put your UIImageView and UITextField inside the UIScrollView without the UIView
and set the contentSize dynamically depending on the size of the text.
to give you an example how i do it:
int contSize = 0;
imageView.frame = CGRectMake(10, 0, 300, 190);
imageView.image = [UIImage imageNamed:#"yourimage"];
contSize = 190 //or add extra space if you dont want your image and your text to be so close
[textField setScrollEnabled:NO];
textField.font = [UIFont systemFontOfSize:15];
textField.textColor = [UIColor grayColor];
textField.text = #"YOUR TEXT";
[textField setEditable:NO];
textField.frame = CGRectMake(5, contSize, 310, 34);
CGRect frameText = textField.frame;
frameText.size.height = textField.contentSize.height;
textField.frame = frameText;
contSize += (textField.contentSize.height);
[scrollView setScrollEnabled:YES];
[scrolView setContentSize:CGSizeMake(320, contSize)];
In the above example I first create an int to keep track of the ysize of my view then Give settings and the image to my UIImageView and add that number to my int then i give settings and text to my UITextField and then i calculate the size of my text depending on how long is my text and the size of my font, then add that to my int and finally assign the contentSize of my ScrollView to match my int.
That way the size of your scrollview will always match your view, and the scrollView will always be at top.
But if you don't want to do all this, you can allways just:
[scrollView setContentOffset:CGPointMake(0, 0) animated:NO];
at the end of the code where you set your image and your text, and the NOto avoid the bouncing.
Hope this helps.
I have a view with multiple subviews. When a user taps a subview, the subview expands in size to cover most of the screen, but some of the other subviews are still visible underneath.
I want my app to ignore touches on the other subviews when one of the subviews is "expanded" like this. Is there a simple way to achieve this? I can write code to handle this, but I was hoping there's a simpler built-in way.
Hope this help...
[[yourSuperView subviews]
makeObjectsPerformSelector:#selector(setUserInteractionEnabled:)
withObject:[NSNumber numberWithBool:FALSE]];
which will disable userInteraction of a view's immediate subviews..Then give userInteraction to the only view you wanted
yourTouchableView.setUserInteraction = TRUE;
EDIT:
It seems in iOS disabling userInteraction on a parent view doesn't disable userInteraction on its childs.. So the code above (I mean the one with makeObjectsPerformSelector:)will only work to disable userInteraction of a parent's immediate subviews..
See user madewulf's answer which recursively get all subviews and disable user interaction of all of them. Or if you need to disable userInteraction of this view in many places in the project, You can categorize UIView to add that feature.. Something like this will do..
#interface UIView (UserInteractionFeatures)
-(void)setRecursiveUserInteraction:(BOOL)value;
#end
#implementation UIView(UserInteractionFeatures)
-(void)setRecursiveUserInteraction:(BOOL)value{
self.userInteractionEnabled = value;
for (UIView *view in [self subviews]) {
[view setRecursiveUserInteraction:value];
}
}
#end
Now you can call
[yourSuperView setRecursiveUserInteraction:NO];
Also user #lxt's suggestion of adding an invisible view on top of all view's is one other way of doing it..
There are a couple of ways of doing this. You could iterate through all your other subviews and set userInteractionEnabled = NO, but this is less than ideal if you have lots of other views (you would, after all, have to subsequently renable them all).
The way I do this is to create an invisible UIView that's the size of the entire screen that 'blocks' all the touches from going to the other views. Sometimes this is literally invisible, other times I may set it to black with an alpha value of 0.3 or so.
When you expand your main subview to fill the screen you can add this 'blocking' UIView behind it (using insertSubview: belowSubview:). When you minimize your expanded subview you can remove the invisible UIView from your hierarchy.
So not quite built-in, but I think the simplest approach. Not sure if that was what you were thinking of already, hopefully it was of some help.
Beware of the code given as solution here by Krishnabhadra:
[[yourSuperView subviews]makeObjectsPerformSelector:#selector(setUserInteractionEnabled:) withObject:[NSNumber numberWithBool:FALSE]];
This will not work in all cases because [yourSuperView subviews] only gives the direct subviews of the superview. To make it work, you will have to iterate recursively on all subviews:
-(void) disableRecursivelyAllSubviews:(UIView *) theView
{
theView.userInteractionEnabled = NO;
for(UIView* subview in [theView subviews])
{
[self disableRecursivelyAllSubviews:subview];
}
}
-(void) disableAllSubviewsOf:(UIView *) theView
{
for(UIView* subview in [theView subviews])
{
[self disableRecursivelyAllSubviews:subview];
}
}
Now a call to disableAllSubviewsOf will do what you wanted to do.
If you have a deep stack of views, the solution by lxt is probably better.
I would do this by putting a custom transparent button with the same frame as the superView. And then on top of that button I would put view that should accept user touches.
Button will swallow all touches and views behind it wouldn't receive any touch events, but view on top of the button will receive touches normally.
Something like this:
- (void)disableTouchesOnView:(UIView *)view {
UIButton *ghostButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, view.frame.size.width, view.frame.size.height)];
[ghostButton setBackgroundColor:[UIColor clearColor]];
ghostButton.tag = 42; // Any random number. Use #define to avoid putting numbers in code.
[view addSubview:ghostButton];
}
And a method for enabling the parentView.
- (void)enableTouchesOnView:(UIView *)view {
[[view viewWithTag:42] removeFromSuperview];
}
So, to disable all views in the parentViev behind yourView, I would do this:
YourView *yourView = [[YourView alloc] initWithCustomInitializer];
// It is important to disable touches on the parent view before adding the top most view.
[self disableTouchesOnView:parentView];
[parentView addSubview:yourView];
Just parentView.UserInteractionEnabled = NO will do the work.
Parent view will disable user interaction on all the view's subviews. But enable it does not enable all subviews(by default UIImageView is not interactable). So an easy way is find the parent view and use the code above, and there is no need to iterate all subviews to perform a selector.
Add a TapGestureRecognizer to your "background view" (the translucent one which "grays out" your normal interface) and set it to "Cancels Touches In View", without adding an action.
let captureTaps = UITapGestureRecognizer()
captureTaps.cancelsTouchesInView = true
dimmedOverlay?.addGestureRecognizer(captureTaps)
I will give my 2 cents to this problem.
Iteratively run userInteractionEnabled = false it's one way.
Another way will be add a UIView like following.
EZEventEater.h
#import <UIKit/UIKit.h>
#interface EZEventEater : UIView
#end
EZEventEater.m
#import "EZEventEater.h"
#implementation EZEventEater
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.backgroundColor = [UIColor clearColor];
self.userInteractionEnabled = false;
}
return self;
}
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//EZDEBUG(#"eater touched");
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
}
In your code you add the EZEventEater view to cover all the views that your may block the touch event.
Whenever you want to block the touch event to those views, simply call
eater.userInteractionEnabled = YES;
Hope this helpful.
In Swift 5, I achieved this behaviour by placing a view right on top(the highlighted one) and setting:
myView.isUserInteractionEnabled = true
This does not let the touches go through it, thus ignoring the taps.
For my app, I think it will be sufficient to disable navigation to other tabs of the app (for a limited duration, while I'm doing some processing):
self.tabBarController.view.userInteractionEnabled = NO;
Also, I disabled the current view controller--
self.view.userInteractionEnabled = NO;
(And, by the way, the recursive solutions proposed here had odd effects in my app. The disable seems to work fine, but the re-enable has odd effects-- some of the UI was not renabled).
Simple solution. Add a dummy gesture that does nothing. Make it reusable by adding it to an extension like this:
extension UIView {
func addNullGesture() {
let gesture = UITapGestureRecognizer(target: self,
action: #selector(nullGesture))
addGestureRecognizer(gesture)
}
#objc private func nullGesture() {}
}
setUserInteractionEnabled = NO on the view you want to disable
I had the same problem, but the above solutions did not help.
I then noticed that calling
super.touchesBegan(...) was the problem.
After removing this the event was only handled by the top-most view.
I hope this is of help to anybody.
Is there a way to make a UIWebView scroll to the top when I touch say a UISearchView within the same viewController (without using Javascript).
Something like this:
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
{
[myWebView scrollToTop]; //pseudocode
}
In other words, what happens when I touch the top bar can also happen programmatically.
CGPoint top = CGPointMake(0, 0); // can also use CGPointZero here
[myWebView.scrollView setContentOffset:top animated:YES];
(Note that if you have set myWebView.scrollView.contentInset.top you will want to take that into account instead of just scrolling to CGPointZero.)
Here's a really ugly, terrible way to do this. I'm answering this to show you what never to do.
for (UIView *subview in webView.subviews)
{
if ([subview isKindOfClass:[UIScrollView class]])
[(UIScrollView*)subview setContentOffset:CGPointZero animated:YES];
}
If you don't want to use JavaScript there's no public API method to do this. UIWebViews don't inherit from scroll views, so you can't use any of the usual methods. As you've figured out, it's possible to do with JavaScript. You can try to find the actual scroll view in the UIWebView, but it's all undocumented and not really a good thing to do in a production app.
Update - as of iOS 5 you can now get direct access to a web view's UIScrollView - see Reconquistador's answer for more information.
Scroll the UIWebView by calling JavaScript through Objective-C:
NSString *script = #"scrollTo(0, 0)";
[webView stringByEvaluatingJavaScriptFromString:script];
For smooth scrolling, use a library like jQuery:
NSString *script = #"$('html, body').animate({scrollTop:0}, 'slow')";
[webView stringByEvaluatingJavaScriptFromString:script];
Access the UIWebView's scrollview and set YES to method scrollsToTop;
WebView.scrollView.scrollsToTop = YES;
Hope this helps!
Swift 3.x
webView.scrollView.setContentOffset(CGPoint.zero, animated: true)
I don't believe you will find any officially supported method to do what you are wanting.
This works for me:
CGPoint topOffset = CGPointMake(0, 0);
//[scrollView setContentOffset: topOffset animated: YES];
[[[webView subviews] lastObject] setContentOffset:topOffset animated:YES];
Where webView is the subclass of the UIWebView, of course.
why not just touch the status bar of your device. for all the scrollView based controls, tableView, webView, scrollView, there is a :
The scroll-to-top gesture is a tap on the status bar; when this property is YES, the scroll view jumps to the top of the content when this gesture occurs. The default value of this property is YES.
Displaying a PDF in a UIWebView, I found you can jump to the top simply by reloading the document.
I've been looking for the past week for the answer to this question.
I have a UIWebView, inside of a UIScrollView. Everything works great, but I want the content of the UIWebView to reset its zoom, when the orientation changes.
In the HTML inside the UIWebView, I set the width of the viewport (w/ a meta tag) to "device-width" and then on the Obj-C side, I set the scalesPagesToFit = YES;
I've tried resetting the zoom with javascript; by replacing the meta tags in runtime; reloading; accessing the UIScrollView inside of the UIWebView; etc...
but with no success.
Any of you gods know a workaround?
The only one I can think off is to recreate the UIWebViews every time we change the orientation, but that makes them flash to white whilst rendering content, which looks terrible :(
Any thoughts?
Many thanks,
Andre
I'm just guessing here and haven't tried, but AFAIK a UIWebView has a UIScrollView child. So one should be able to do:
for (UIScrollView *scroll in [myWebView subviews]) {
// Make sure it really is a scroll view and reset the zoom scale.
if ([scroll respondsToSelector:#selector(setZoomScale:)])
[scroll setZoomScale:1.0];
}
On iOS 5+ you have access to scrollView.
Just do:
[webView.scrollView setZoomScale:1.0];
If you want to do it programmatically this is the only way I could find to accomplish it: (specify your own sizes if you wish, i was attempting to zoom out after typing into a form field)
UIScrollView *sv = [[webViewView subviews] objectAtIndex:0];
[sv zoomToRect:CGRectMake(0, 0, sv.contentSize.width, sv.contentSize.height) animated:YES];
Update:
Downscaling wasn't working properly when using
[[[webView subviews] lastObject] setZoomScale:0.25];
The quality of the images being downscaled on the page was awful. Doing:
[[[webView subviews] lastObject] setZoomScale:0.25 animated:YES];
Fixed it. So that last line is the one you could use.
webView was subclassed of a UIWebView which lies on some IB file. I didn't use the Viewport at all. I find that one should pick by either doing this from the Cocoa Touch side or use JS.
I used:
webView.scalesPageToFit = YES;
I wonder if there's a way of resetting the scalesPageToFit.
Adapting from Captnwalker1's answer, I came up with this:
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
if(toInterfaceOrientation ==UIInterfaceOrientationPortrait||toInterfaceOrientation==UIInterfaceOrientationMaskPortraitUpsideDown)
{
currentScrollView = [[webView subviews] objectAtIndex:0];
[currentScrollView zoomToRect:CGRectMake(0, 0, currentScrollView.contentSize.width, currentScrollView.contentSize.height) animated:NO];
}
else
{
currentScrollView = [[webView subviews] objectAtIndex:0];
[currentScrollView zoomToRect:CGRectMake(0, 0, currentScrollView.contentSize.width, currentScrollView.contentSize.height) animated:NO];
}
}
So load your webview image, and the image will reset it's size when rotated.
Okay, this is the code:
[lblMessage setText: txtEnter.text];
[lblMessage sizeToFit];
scrollingTextView.contentSize = lblMessage.frame.size;
float width = (lblMessage.frame.size.width) + (480);
[UIView beginAnimations:#"pan" context:nil];
[UIView setAnimationDuration:durationValue];
[UIView setAnimationRepeatCount:5];
scrollingTextView.contentOffset = CGPointMake(width,0);
[UIView commitAnimations];
//The scrolling text view is rotated.
scrollingTextView.transform = CGAffineTransformMakeRotation (3.14/2);
[self.navigationController setNavigationBarHidden:YES];
btnChange.transform = CGAffineTransformMakeRotation (3.14/2);
I have the user enter in some text, press a button and then a label is replaced with the text, turned 90 degrees in a scrollview on a page.
After a certain number of characters, for example say 20.. the animation just won't load. I can go back down until the animation will run.
Any ideas on where I am going wrong, or a better way of storing the text etc etc ?
Core Animation animations are performed on a separate thread. When you enclose the change in contentOffset in a beginAnimations / commitAnimations block, that change will be animated gradually. The scrolling text view rotation that occurs next, outside of the animation block, will be performed instantly. Since both are interacting with the same control on different threads, it's not surprising that you're getting weird behavior.
If you want to animate the rotation of the text in the same way as the contentOffset, move that line of code to within the animation block.
If you want to have the rotation occur after the offset change animation has completed, set up a callback delegate method. You can use code in the beginning of your animation block similar to the following:
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(contentOffsetAnimationHasFinished:finished:context:)];
which requires you to implement a delegate method like the following:
- (void)contentOffsetAnimationHasFinished:(NSString *)animationID finished:(BOOL)finished context:(void *)context;
{
// Do what you need to, now that the first animation has completed
}
EDIT (2/6/2009):
I just created a simplified version of your application, using only the sideways text scrolling, and find no problem with the animation on the device with any number of characters. I removed all extraneous calls to layout the buttons, etc., and only animate the text. Rather than apply the rotation transform to the scroll view every time you click the button, I have it start rotated and stay that way.
I thought it might be a layer size issue, as the iPhone has a 1024 x 1024 texture size limit (after which you need to use a CATiledLayer to back your UIView), but I was able to lay out text wider than 1024 pixels and still have this work.
A full Xcode project demonstrating this can be downloaded here. I don't know what your issue is, but it's not with the text animating code you present here.
Right, this code is working fine in the simulator, and works fine until i enter more than say 20 characters in txtEnter.text:
- (IBAction)updateMessage:(id)sender
{
//Animation coding
//Put the message in a resize the label
[lblMessage setText: txtEnter.text];
[lblMessage sizeToFit];
//Resize the scrolliew and change the width.
scrollingTextView.contentSize = lblMessage.frame.size;
float width = (lblMessage.frame.size.width) + (480);
scrollingTextView.transform = CGAffineTransformMakeRotation (3.14/2);
//Begin the animations
[UIView beginAnimations:#"pan" context:nil];
[UIView setAnimationDuration:durationValue];
[UIView setAnimationRepeatCount:5];
//Start the scrolling text view to go across the screen
scrollingTextView.contentOffset = CGPointMake(width,0);
[UIView commitAnimations];
//General hiding and showing points.
[txtEnter resignFirstResponder];
[btnChange setHidden:NO];
[txtEnter setHidden:YES];
[btnUpdate setHidden:YES];
[lblSpeed setHidden:YES];
[lblBackground setHidden:YES];
[backgroundColourControl setHidden:YES];
[speedSlider setHidden:YES];
[scrollingTextView setHidden:NO];
[backgroundImg setHidden:NO];
[toolbar setHidden:YES];
[self.navigationController setNavigationBarHidden:YES animated:YES];
//Depending on the choice from the segment control, different colours are loaded
switch([backgroundColourControl selectedSegmentIndex] + 1)
{
case 1:
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackTranslucent animated:YES];
break;
case 2:
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque animated:YES];
break;
default: break;
}
btnChange.transform = CGAffineTransformMakeRotation (3.14/2);
}
I've tried your method Brad, but can't seem to get the (void) section to work properly.
What my app does its fill the label with a message and then rotates them all to act like it's in landscape mode. Then what it does it scroll the label within a scrollview to act like a scrolling message across the screen.