Does anyone know how to stop a UIWebView from bouncing vertically? I mean when a user touches their iphone screen, drags their finger downwards, and the webview shows a blank spot above the web page I had loaded?
I've looked at the following possible solutions, but none of them worked for me:
http://www.iphonedevsdk.com/forum/iphone-sdk-development/996-turn-off-scrolling-bounces-uiwebview.html
http://forums.macrumors.com/showthread.php?t=619534
How do I stop a UIScrollView from bouncing horizontally?
for (id subview in webView.subviews)
if ([[subview class] isSubclassOfClass: [UIScrollView class]])
((UIScrollView *)subview).bounces = NO;
...seems to work fine.
It'll be accepted to App Store as well.
Update: in iOS 5.x+ there's an easier way - UIWebView has scrollView property, so your code can look like this:
webView.scrollView.bounces = NO;
Same goes for WKWebView.
I was looking at a project that makes it easy to create web apps as full fledged installable applications on the iPhone called QuickConnect, and found a solution that works, if you don't want your screen to be scrollable at all, which in my case I didn't.
In the above mentioned project/blog post, they mention a javascript function you can add to turn off the bouncing, which essentially boils down to this:
document.ontouchmove = function(event){
event.preventDefault();
}
If you want to see more about how they implement it, simply download QuickConnect and check it out.... But basically all it does is call that javascript on page load... I tried just putting it in the head of my document, and it seems to work fine.
Well all I did to accomplish this is :
UIView *firstView = [webView.subviews firstObject];
if ([firstView isKindOfClass:[UIScrollView class]]) {
UIScrollView *scroll = (UIScrollView*)firstView;
[scroll setScrollEnabled:NO]; //to stop scrolling completely
[scroll setBounces:NO]; //to stop bouncing
}
Works fine for me...
Also, the ticked answer for this question is one that Apple will reject if you use it in
your iphone app.
In the iOS 5 SDK you can access the scroll view associated with a web view directly rather than iterating through its subviews.
So to disable 'bouncing' in the scroll view you can use:
myWebView.scrollView.bounces = NO;
See the UIWebView Class Reference.
(However if you need to support versions of the SDK before 5.0, you should follow Mirek Rusin's advice.)
Swift 3
webView.scrollView.bounces = false
Warning. I used setAllowsRubberBanding: in my app, and Apple rejected it, stating that non-public API functions are not allowed (cite: 3.3.1)
In Swift to disable bounces
webViewObj.scrollView.bounces = false
Brad's method worked for me. If you use it you might want to make it a little safer.
id scrollView = [yourWebView.subviews objectAtIndex:0];
if( [scrollView respondsToSelector:#selector(setAllowsRubberBanding:)] )
{
[scrollView performSelector:#selector(setAllowsRubberBanding:) withObject:NO];
}
If apple changes something then the bounce will come back - but at least your app won't crash.
On iOS5 only if you plan to let the users zoom the webview contents (e.i.: double tap) the bounce setting isn't enough. You need to set also alwaysBounceHorizontal and alwaysBounceVertical properties to NO, else when they zoom-out (another double tap...) to default it will bounce again.
I traversed the collection of UIWebView's subviews and set their backgrounds to [UIColor blackColor], the same color as the webpage background. The view will still bounce but it will not show that ugly dark grey background.
It looks to me like the UIWebView has a UIScrollView. You can use documented APIs for this, but bouncing is set for both directions, not individually. This is in the API docs.
UIScrollView has a bounce property, so something like this works (don't know if there's more than one scrollview):
NSArray *subviews = myWebView.subviews;
NSObject *obj = nil;
int i = 0;
for (; i < subviews.count ; i++)
{
obj = [subviews objectAtIndex:i];
if([[obj class] isSubclassOfClass:[UIScrollView class]] == YES)
{
((UIScrollView*)obj).bounces = NO;
}
}
I was annoyed to find out that UIWebView is not a scroll view, so I made a custom subclass to get at the web view's scroll view. This suclass contains a scroll view so you can customize the behavior of your web view. The punchlines of this class are:
#class CustomWebView : UIWebview
...
- (id) initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
// WebViews are subclass of NSObject and not UIScrollView and therefore don't allow customization.
// However, a UIWebView is a UIScrollViewDelegate, so it must CONTAIN a ScrollView somewhere.
// To use a web view like a scroll view, let's traverse the view hierarchy to find the scroll view inside the web view.
for (UIView* v in self.subviews){
if ([v isKindOfClass:[UIScrollView class]]){
_scrollView = (UIScrollView*)v;
break;
}
}
return self;
}
Then, when you create a custom web view, you can disable bouncing with:
customWebView.scrollView.bounces = NO; //(or customWebView.scrollView.alwaysBounceVertically = NO)
This is a great general purpose way to make a web view with customizable scrolling behavior. There are just a few things to watch out for:
as with any view, you'll also need to override -(id)initWithCoder: if you use it in Interface Builder
when you initially create a web view, its content size is always the same as the size of the view's frame. After you scroll the web, the content size represents the size of the actual web contents inside the view. To get around this, I did something hacky - calling -setContentOffset:CGPointMake(0,1)animated:YES to force an unnoticeable change that will set the proper content size of the web view.
Came across this searching for an answer and I eventually just lucked on an answer of my own by messing about. I did
[[webview scrollView] setBounces:NO];
and it worked.
This worked for me, and beautifully too (I am using phonegap with webView)
[[webView.webView scrollView] setScrollEnabled:NO];
or
[[webView scrollView] setScrollEnabled:NO];
I tried a slightly different approach to prevent UIWebView objects from scrolling and bouncing: adding a gesture recognizer to override other gestures.
It seems, UIWebView or its scroller subview uses its own pan gesture recognizer to detect user scrolling. But according to Apple's documentation there is a legitimate way of overriding one gesture recognizer with another. UIGestureRecognizerDelegate protocol has a method gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: - which allows to control the behavior of any colliding gesture recognizers.
So, what I did was
in the view controller's viewDidLoad method:
// Install a pan gesture recognizer // We ignore all the touches except the first and try to prevent other pan gestures
// by registering this object as the recognizer's delegate
UIPanGestureRecognizer *recognizer;
recognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePanFrom:)];
recognizer.delegate = self;
recognizer.maximumNumberOfTouches = 1;
[self.view addGestureRecognizer:recognizer];
self.panGestureFixer = recognizer;
[recognizer release];
then, the gesture override method:
// Control gestures precedence
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
// Prevent all panning gestures (which do nothing but scroll webViews, something we want to disable in
// the most painless way)
if ([otherGestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]])
{
// Just disable every other pan gesture recognizer right away
otherGestureRecognizer.enabled = FALSE;
}
return NO;
}
Of course, this delegate method can me more complex in a real application - we may disable other recognizers selectively, analyzing otherGestureRecognizer.view and making decision based on what view it is.
And, finally, for the sake of completeness, the method we registered as a pan handler:
- (void)handlePanFrom:(UIPanGestureRecognizer *)recognizer
{
// do nothing as of yet
}
it can be empty if all we want is to cancel web views' scrolling and bouncing, or it can contain our own code to implement the kind of pan motions and animations we really want...
So far I'm just experimenting with all this stuff, and it seems to be working more or less as I want it. I haven't tried to submit any apps to iStore yet, though. But I believe I haven't used anything undocumented so far... If anyone finds it otherwise, please inform me.
Here's two newer potential solutions. Apparently, you can use jqtouch or pastrykit to disable scrolling. However, I haven't got these to work. You might be more competent.
turning off vertical scrolling
digging into pastrykit
fixed positioning on mobile safari
This link helped me lot.....Its easy.. There is a demo..
(Xcode 5 iOS 7 SDK example) Here is a Universal App example using the scrollview setBounces function. It is an open source project / example located here: Link to SimpleWebView (Project Zip and Source Code Example)
One of the subviews of UIWebView should be a UIScrollView. Set its scrollEnabled property to NO and the web view will have scrolling disabled entirely.
Note: this is technically using a private API and thus your app could be rejected or crash in future OS releases. Use #try and respondsToSelector
Look into the bounces property of UIScrollView. Quoth the Apple docs:
If the value of the property is YES (the default), the scroll view bounces when it encounters a boundary of the content. Bouncing visually indicates that scrolling has reached an edge of the content. If the value is NO, scrolling stops immediately at the content boundary without bouncing.
Make sure you're using the right UIScrollView. I'm not sure what the hierarchy looks like for a UIWebView, but the scroll view could be a parent, not a child, of the UIWebView.
To disable UIWebView scrolling you could use the following line of code:
[ObjWebview setUserInteractionEnabled:FALSE];
In this example, ObjWebview is of type UIWebView.
webView.scrollView.scrollEnabled=NO;
webView.scrollView.bounces=NO;
Related
Here's how the scroll views work: One scroll view is paging enabled in the horizontal direction. Each 'page' of this scroll view contains a vertically scrolling UITableView. Without modification, this works OK, but not perfectly.
The behaviour that's not right: When the user scrolls up and down on the table view, but then wants to flick over to the next page quickly, the horizontal flick/swipe will not work initially - it will not work until the table view is stationary (even if the swipe is very clearly horizontal).
How it should work: If the swipe is clearly horizontal, I'd like the page to change even if the table view is still scrolling/bouncing, as this is what the user will expect too.
How can I change this behaviour - what's the easiest or best way?
NOTE For various reasons, a UIPageViewController as stated in some answers will not work. How can I do this with cross directional UIScrollViews (/one is a table view, but you get the idea)? I've been banging my head against a wall for hours - if you think you can do this then I'll more than happily award a bounty.
According to my understanding of the question, it is only while the tableView is scrolling we want to change the default behaviour. All the other behaviour will be the same.
SubClass UITableView. UITableViews are subClass of UIScrollViews. On the UITableView subClass implement one UIScrollView's UIGestureRecognizer's delegate method
- (BOOL)gestureRecognizer:(UIPanGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UISwipeGestureRecognizer *)otherGestureRecognizer
{
//Edit 1
//return self.isDecelerating;
//return self.isDecelerating | self.bounces; //If we want to simultaneous gesture on bounce and scrolling
//Edit 2
return self.isDecelerating || self.contentOffset.y < 0 || self.contentOffset.y > MAX(0, self.contentSize.height - self.bounds.size.height); // #Jordan edited - we don't need to always enable simultaneous gesture for bounce enabled tableViews
}
As we only want to change the default gesture behaviour while the tableView is decelerating.
Now change all 'UITableView's class to your newly created tableViewSubClass and run the project, swipe should work while tableView is scrolling. :]
But the swipe looks a little too sensitive while tableView is scrolling. Let's make the swipe a little restrictive.
SubClass UIScrollView. On the UIScrollView subclass implement another UIGestureRecognizer's delegate method gestureRecognizerShouldBegin:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
CGPoint velocity = [(UIPanGestureRecognizer *)gestureRecognizer velocityInView:self];
if (abs(velocity.y) * 2 < abs(velocity.x)) {
return YES;
}
}
return NO;
}
We want to make the "swipe is clearly horizontal". Above code only permits gesture begin if the gesture velocity on x axis is double than on y axis. [Feel free to increase the hard coded value "2" if your like. The higher the value the swipe needs to be more horizontal.]
Now change the `UiScrollView' class (which has multiple TableViews) to your ScrollViewSubClass. Run the project. :]
I've made a project on gitHub https://github.com/rishi420/SwipeWhileScroll
Although apple doesn't like this method too much:
Important: You should not embed UIWebView or UITableView objects in UIScrollView objects. If you do so, unexpected behavior can result
because touch events for the two objects can be mixed up and wrongly
handled.
I've found a great way to accomplish this.
This is a complete solution for the problem. In order to scroll the UIScrollView while your UITableView is scrolling you'll need to disable the interaction you have it.
- (void)viewDidLoad
{
[super viewDidLoad];
_myScrollView.contentSize = CGSizeMake(2000, 0);
data = [[NSMutableArray alloc]init];
for(int i=0;i<30;i++)
{
[data addObject:[NSString stringWithFormat:#"%d",i]];
}
UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
[self.view addGestureRecognizer:tap];
}
- (void)handleTap:(UITapGestureRecognizer *)recognizer
{
[_myTableView setContentOffset:_myTableView.contentOffset animated:NO];
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
scrollView.userInteractionEnabled = NO;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
scrollView.userInteractionEnabled = YES;
}
To sum up the code above, if the UITableView is scrolling, set userInteractionEnabled to NO so the UIScrollView will detect the swipe. If the UITableView is scrolling and the user taps on the screen, userInteractionEnabled will be set to YES.
Instead of using UIScrollView as a container for these multiple table views, try using a UIPageViewController.
You can even integrate this into your existing view controller setup as a child view controller (directly replacing the UIScrollView).
In addition, you'll likely want to implement the required methods from UIPageViewControllerDataSource and possibly one or more of the methods from UIPageViewControllerDelegate.
Did you try the methods : directionalLockEnabled of both your table and scroll and set them up to horizontal for one and vertical for the other ?
Edit :
1)
What you want to do is very complicate since the touch wait some time (like 0.1s) to know what your movement will be. And if your table is moving, it will take your touch immediately whatever it is (because it's suppose to be reactive movement on it).
I don't see any other solution for you but to override touch movement from scratch to detect immediately the kind of mouvement you want (like if the movement will be horizontal) but it will be more than hard to do it good.
2)
Another solution I can advise you is to make your table have left and right margin, where you can touch the parent scroll (pages thing so) and then even if your table is scrolling, if you touch here, only your paging scroll will be touched. It's simpler, but could not fit with your design maybe...
Use UIPageViewController and in the -viewDidLoad method (or any other method what best suits your needs or design) get UIPageViewController's UIScrollView subview and assign a delegate to it. Keep in mind that, its delegate property won't be nil. So optionally, you can assign it to another reference, and then assign your object, which conforms to UIScrollViewDelegate, to it. For example:
id<UIScrollViewDelegate> originalPageScrollViewDelegate = ((UIScrollView *)[pageViewController.view.subviews objectAtIndex:0]).delegate;
[((UIScrollView *)[pageViewController.view.subviews objectAtIndex:0]) setDelegate:self];
So that you can implement UIScrollViewDelegate methods with ease. And your UIPageViewController will call your delegate's -scrollViewDidScroll: method.
By the way, you may be obliged to keep original delegate, and respond to delegate methods with that object. You can see an example implementation in ViewPagerController class on my UI control project here
I faced the same thing recently. My UIScrollview was on paging mode and every page contained a UITableView and like you described it worked but not as you'd expected it to work. This is how solved it.
First I disabled the scrolling of the UIScrollview
Then I added a UISwipeGestureRecognizer to the actual UITableView for left and right swipes.
The action for those swipes were:
[scroll setContentOffset:CGPointMake(currentPointX + 320, PointY) animated:YES];
//Or
[scroll setContentOffset:CGPointMake(currentPointX - 320 , PointY) animated:YES];
This works flawlessly, the only down side is that if the user drags his finger on the UITableVIew that will be considered as a swipe. He won't be able to see half of screen A and half of screen B on the same screen.
You could subclass your scroll view and your table views, and add this gesture recognizer delegate method to each of them...
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:
(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
I can't be sure this is exactly what you are after, but it may come close.
I am trying to implement a view with sliding side menus, such as with PKRevealController in iOS 6.1. A simple demo of this issue with source code on github is here, however you might not need to grab it if you already understand gestureRecognizer delegate implementation.
The problem I see is that two gestures that my users will want to use are going to be mutually confused for each other. The UITableView in the center (main screen) of the application should be able to use the swipe-right gesture to delete, but I still want a swipe that occurs across the top navigation area to result in exposing the side menus.I also intend to show other things than just the Table view, and at runtime I plan to swap out the main view with a different view, whenever a user selects a button on one of the side menus. This is kind of like a "hidden side tray UITabBarController" that I'm going for, but I want the side bars to be revealed only when the main "front view" controller is NOT a UITableView or its subviews.
Right now, using the demo sources that comes with PKRevealController, and adding deletion support to the main view's UITableView, no slide gesture to delete a row is possible. (You have to add one table view method to enable deletion support in the UITable view, which I did add.)
This was asked here, but the answer stated is incomplete, and as seen below, does not work for me and I have no idea why, because it appears that this delegate method is not invoked at any time where I return a YES, and yet it goes ahead anyways and begins a gesture.
Update The answer in the previous question is also wrong, as compared to the WIKI/FAQ answer I placed below.
I have only modified the class PKRevealController.m by adding this:
- (BOOL) gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
UIView *view1 = otherGestureRecognizer.view;
UIView *view2;
if (view1) {
view2 = view1.superview;
};
if ([gestureRecognizer.view isKindOfClass:[UITableView class]])
{
return NO;
}
// Co-operate by not stealing gestures from UITableView.
if ([view1 isKindOfClass:[UITableView class]]) {
return NO;
}else if ([view1 isKindOfClass:[UITableViewCell class]]) {
return NO;
// UITableViewCellContentView
}
else if (view2 && [view2 isKindOfClass:[UITableViewCell class]]) {
return NO;
// UITableViewCellContentView
}
else
{
return YES; // NEVER GETS HIT. BREAKPOINT HERE!
}
}
What confuses me is that at no point does the return YES code above get hit (I have a breakpoint on it) and yet, the Gesture controller is still stealing the gesture.
Note: I have made an evil hack, but I thought that I could prevent this cleanly. Here is my evil hack:
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if (gestureRecognizer == self.revealPanGestureRecognizer)
{
CGPoint translation = [self.revealPanGestureRecognizer translationInView:self.frontViewContainer];
BOOL begin = (fabs(translation.x) >= fabs(translation.y));
// BEGIN EVIL HACK
if (_topLimitY > 0) {
CGPoint location = [gestureRecognizer locationInView:gestureRecognizer.view];
if (location.y>_topLimitY) // _topLimitY = 55 for instance.
begin = NO;
}
// END EVIL HACK.
return begin;
}
else if (gestureRecognizer == self.revealResetTapGestureRecognizer)
{
return ([self isLeftViewVisible] || [self isRightViewVisible]);
}
return YES;
}
Right now in my evil hacked demo, I have set the topLimitY property (that I added to PKRevealController's properties) to 55, which allows me to swipe on the nav bar area of the front view, but not on the table view which takes up the rest of the demo.
Note that I plan to have multiple main views, and only want to defeat the gesture recognition on the whole main area if the view is a UITableView or some sub-view thereof. That is why I call my hack above a hack. Because I thought you could tell the gesture recognizer to go away and not bother you, and yet it doesn't work, it doesn't even invoke the shouldRecognize method, it just goes ahead and does the next thing in its list of things to do.
I should really read the WIKI first shouldn't I?
This is a FAQ, it says so right here:
When instantiating the controller pass this option in your options dictionary:
NSDictionary *options = #{
PKRevealControllerRecognizesPanningOnFrontViewKey : #NO
};
This will disable pan-based reveal for the entire front view. Now, you can use the revealPanGestureRecognizer and add it to any view you desire to be panned on that doesn't interfere with your table view, to enable gesture based reveal.
I'd advise (if working with a table based environment with swipe'able cells) you, to add the revealPanGestureRecognizer to your front view controller's navigation bar (which it most likely has):
[self.navigationController.navigationBar addGestureRecognizer:self.revealController.revealPanGestureRecognizer];
And voilà - panning doesn't interfere with your table view anymore.
more info at:
https://github.com/pkluz/PKRevealController/issues/76
Thank you Wiki. If only I had read it all first.
The above completely answers my question and was already there on the wiki. I'm answering my own question because it seems Google always comes to Stackoverflow first, and that might help other confused developers in the future.
Update If the above thing blows up when you try it, it's probably being done too early. Here's a slightly more robust version of the above fix:
// Additional gesture recognition linkups. The underscore variables here
// are implementation-section ivars in my app-delegate, that I have already
// checked are valid and initialized, and this is the last thing in my app delegate
// didFinishLaunch... method, before the return YES:
UIGestureRecognizer *rec = _revealController.revealPanGestureRecognizer;
if (rec) {
[_frontViewNavController.navigationBar addGestureRecognizer:rec];
}
Use This :
self.revealController.frontViewController.revealController.recognizesPanningOnFrontView = YES;
all, I'm a newbie on ios development.
I want to implement a right swipe gesture to UIWebView, which should have the action specified by me. However, the when the web page is too large that causes the UIWebView has a scroll bar, then my custom left swipe gesture doesn't work at all. In this case, when I swipe right, then the scroll bar will move, instead of triggering my specified action. Is there any way to disable the scroll bar moving action when I swipe right?
Hope my question is clear to you ...
Thanks in advance.
Either add a transparent view over the webview, or make a subclass of UIWebView and override the touchmethods.
you can disable the whole scroll in the UIWebView like this
UIScrollView *scroll = [[webView subviews] lastObject];
if([scroll isKindOfClass:[UIScrollView class]])
{
scroll = (UIScrollView*)scroll;
[scroll setScrollEnabled:NO];
}
How can I programmatically scroll a UIWebView in Objective-C (iOS)?
The only solution I can think of is to put it inside a UIScrollView and programmatically scroll that, however this presents the problem that the web view is often the wrong size and therefore the bottom of the page is cut off when scrolling. I have no idea how to programatically change the size of a web view to fit its content either... so far I have:
UIView *webDocView = webView.subviews.lastObject;
webView.frame = CGRectMake(webView.frame.origin.x, webView.frame.origin.y, webView.frame.size.width, webDocView.frame.size.height);
But for some reason this will not work.
Should I persue the solution of using a ScrollView... or is there a better way to do this?
UIWebView doesn't have any properties that specify its position on the document it is rendering. You likely need to do this through Javascript, if you want the animated feel of it take a look at this. http://www.learningjquery.com/2007/09/animated-scrolling-with-jquery-12
Apple says: "You should not embed UIWebView objects in UIScrollView object. If you do so, unexpected behavior can result because touch events for the two objects can be mixed up and wrongly handled." This probably has a lot to do with instances of both UIWebView and UIScrollView being scrollable and the interaction of two scrolling requests is too much.
Here is a simple solution that I've tested and it works:
Add the following in viewDidLoad to add a scrollView on top of our webView:
self.scrollView = [[UIScrollView alloc] init];
self.scrollView.delegate = self;
[self.webView addSubview:self.scrollView];
When the page loads, we adjust the frame and contentSize of the scrollView
-(void) webViewDidFinishLoad:(UIWebView *)webView {
self.scrollView.frame = webView.bounds;
self.scrollView.contentSize = webView.scrollView.contentSize;
}
Now you can change offset of the web view.scrollView by setting self.webView.scrollView.contentOffset to whatever CGPoint that you want programatically.
Remember that, by doing this, touch events are no longer passed to the webiview. If you want the web view to still respond to the user dragging, then also do this:
#pragma mark UIScrollView Delegate
-(void) scrollViewDidScroll:(UIScrollView *)scrollView {
self.webView.scrollView.contentOffset = scrollView.contentOffset;
}
I have a UIWebView with some content and I need to make its scroll indicator visible for a short time (like [UIScrollView flashScrollIndicators]).
Any idea how to do this?
Starting iOS 5.0 onwards, one can now customize the scrolling behavior of UIWebView by accessing the 'scrollview' property to achieve the desired functionality:
[webView.scrollView flashScrollIndicators];
There's no real way of doing this via a published API, however I think that in this case it's OK to guess the UIScrollView subview, so long as you make sure your application doesn't crash if you can't find the UIScrollView:
UIView* scrollView = [webView.subviews objectAtIndex:0];
if ([scrollView isKindOfClass:[UIScrollView class]) {
[((UIScrollView*)scrollView) flashScrollIndicators];
} else {
// If Apple changes the view hierarchy you won't get
// a flash, but that doesn't matter too much
}
EDIT: The above will not work because the first subview of a UIWebView is a UIScroller, not a UIScrollView (my memory might be playing tricks on me). Perhaps try the following?
UIView* uiScroller = [webView.subviews objectAtIndex:0];
if ([uiScroller respondsToSelector:#selector(displayScrollerIndicators)]) {
[((UIScrollView*)uiScroller) performSelector:#selector(displayScrollerIndicators)];
} else {
// If Apple changes the view hierarchy you won't get
// a flash, but that doesn't matter too much
}