I'm running into a case where I have in-application HTML documentation that uses a dark background, but the default scroll indicator for UIWebView is getting lost in that background. The following is an example of this:
(source: sunsetlakesoftware.com)
With UIScrollView, which UIWebView resembles in its behavior, you can set the indicatorStyle property to UIScrollViewIndicatorStyleWhite, which results in the desired behavior:
(source: sunsetlakesoftware.com)
I can't seem to find a similar property in the exposed interface for UIWebView. Is there a CSS trick or other way to force the scroll indicator to a lighter style?
Starting iOS 5.0 onwards, one can now customize the scrolling behavior of the web view by accessing the 'scrollview' property to achieve the desired functionality:
webView.scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
If you do want to scan the subviews and attempt to gracefully fail if something changes in the future this currently works:
//set a white scroll bar
for (UIView *subview in [webView subviews]) {
if ([subview isKindOfClass:NSClassFromString(#"UIScroller")] || [subview isKindOfClass:NSClassFromString(#"UIScrollView")]) {
if ([subview respondsToSelector:#selector(setIndicatorStyle:)]) {
[(UIScrollView *)subview setIndicatorStyle:UIScrollViewIndicatorStyleWhite];
}
break;
}
}
Though things could still break in the future if setIndicatorStyle: changes to expect a non-enumerated value... but I doubt that would happen.
Scan the subviews and test for a UIScrollView. You can then programatically set the indicator.
There is no public API for this in the 2.x SDK. File a bug/case/radar asking for it in 3.0.
Related
I saw one app in which the notification/alert view was coming from the top of the iphone screen with gradient black color.
May I have details about alert/notification styles if any?
you may use this link ... maybe it will help you. one other way is to use UIActionsheet.
http://joris.kluivers.nl/blog/2009/04/23/subclass-uialertview-to-create-a-custom-alert/
There's the UIActionSheet—but it is raises from the bottom.
Unfortunately not. And customize the original UIAlertView is a trick, that acts on subviews hierarchies. you can sub class it and change it's background color overriding the drawRect: method and removing the original background with those lines of code
- (void)didAddSubview:(UIView *)subview {
if ([subview isMemberOfClass:[UIImageView class]]) {
[subview removeFromSuperview];
}
}
But it is a trick and it could be lost in future release of iOS
I'm using a UIWebView to display a variety of file types (so I can't use a specialized PDF viewer) embedded into my main view (so I can't use a modal document interaction controller). My main view has a background design that clashes with the light gray frame that appears around documents in the UIWebView. Does anyone know a way to remove that gray frame, make it transparent or change its color?
I'm familiar with and have used the techniques for changing the background color of the UIWebView to avoid a "color flash" while it loads, and for removing the top and bottom shadow that appear when "overscrolling" the web view, but I haven't seen anyone address this gray frame. (It only appears when displaying documents like .doc or .pdf, not when displaying HTML content.) I've hidden all the images that are subviews of the UIWebView's scroll view, so apparently this is coming from somewhere else.
This question was written while iOS 4 was current, but in iOS 5 and later, simply setting the backgroundColor and opaque properties of the UIWebView will remove that gray frame:
myWebView.opaque = NO;
myWebView.backgroundColor = [UIColor clearColor];
You can change WebView's background color by assigning its backgroundColor property:
myWebView.backgroundColor = [UIColor redColor]; // will make red bakground
If you want transparency use [UIColor clearColor] instead. But remember - by making your views tranparent you can worsen app's performance.
Since this has been around for a while I'll just throw some ideas out there.
You may be able to utilize the stringByEvaluatingJavaScriptFromString: method of the UIWebView class to manipulate the document object model if the UIWebView treats the loaded document as a page, but this method has some limitations.
Other than that, the only thing you really have left at your disposal is manipulating the view hierarchy to modify any subviews of the UIWebView, but there may not be anything for you manipulate if the UIWebView class renders the viewer directly rather than creating a hierarchy.
It looks like it is not possible to remove the border from a UIWebView but could you not use CGContextDrawPDFPage() as Apple show here: http://developer.apple.com/library/ios/#samplecode/ZoomingPDFViewer/Introduction/Intro.html
Try this,
self.webview.backgroundColor = [UIColor whiteColor];
for (UIView* subView in [self.webview subviews])
{
if ([subView isKindOfClass:[UIScrollView class]]) {
for (UIView* shadowView in [subView subviews])
{
if ([shadowView isKindOfClass:[UIImageView class]]) {
[shadowView setHidden:YES];
}
}
}
}
This may help you. :-)
You need a bunch of CoreAnimation magic:
- (void) hideShadowInLayer:(CALayer *) layer
{
for (CALayer *l in layer.sublayers) {
l.shadowOpacity = 0;
[self hideShadowInLayer:l];
}
}
- (void) hideShadows
{
[CATransaction begin];
[CATransaction setValue:(id) kCFBooleanTrue forKey:kCATransactionDisableActions];
[self hideShadowInLayer:webView.layer];
[CATransaction commit];
}
You need to perform hideShadows method somewhere AFTER loading your document and while you are scrolling it (I guess scrollViewDidScroll of webView.scrollView.delegate is a good place). You also need to include QuartzCore framework to your project.
What's going on here:
Any view uses something called layer for rendering. Layers can have its own hierarchy and every layer can have its own border and shadow, so the frame that annoying you is the shadow of one of them. Bad thing - UIWebView recreates it while scrolling - so you need to use this method constantly. And I guess shadowOpacity has a default animation attached to it, so you need CATransaction to disable it.
I know that this is possible in the Tweetie for iPhone or the xkcd iPhone app, but they are using a table. Any idea if this can be done for a simple UIWebView as well? I'm aware of the Javascript suggestions in this SO question, but what about making that natively?
To retrieve scroll events on UIWebView I personnaly use this code to get the scrollview that is inside the UIWebView :
- (void) addScrollViewListener
{
UIScrollView* currentScrollView;
for (UIView* subView in self.myWebView.subviews) {
if ([subView isKindOfClass:[UIScrollView class]]) {
currentScrollView = (UIScrollView*)subView;
currentScrollView.delegate = self;
}
}
}
It's working. You can also use it to call [(UIScrollView*)subView setContentOffset:offSet animated:YES]; The only problem may be not to pass Apple code checking. I don't know yet since I'm still in coding phase.
Anyone tried that yet ?
FYI, iOS 5 has officially introduced the property scrollView in UIWebView. I tested it. It worked perfectly with EGO's pull and refresh code. So the problem is no longer a problem for any iOS 5 devices.
For downward compatibility, you still need #CedricSoubrie's code though.
To tell the truth, UIWebVIew class has an undocumented getter method called _scrollView;
So the code goes:
scrollView = [webView _scrollView];
To get a reference for the UIScrollView in UIWebView, simply search it by iterating trough subviews.
for(id eachSubview in [webView subviews]){
if ([eachSubview isKindOfClass:[UIScrollView class]]){
scrollView = eachSubview;
break;
}
}
After that you can easily wire up things to your EGORefreshTableHeaderView interface with the UIWebView and the UIScrollView delegate callbacks.
I'm having a really hard time understanding delegates and object inheritance (if I may use this word) and I think I need a simple (or so I think) thing: catch scrollViewDidScroll event in UIWebView and get offset (basically, just to know if scroll is not on top/bottom, so I could hide navigation and tab bars).
Is there any way I could do it? I already using UIWebviewDelegate in my view controller to "shouldStartLoadWithRequest". Maybe I could some how use UIScrollViewDelegate too for scrollViewDidScroll? If yes, then how?
I really have trouble understanding delegates. I've red some articles, but still, in practice, I can't manage to use them.
Any help or info would be lovely.
Thank you in advance!
To retrieve scroll events on UIWebView I personnaly use this code to get the scrollview that is inside the UIWebView :
- (void) addScrollViewListener
{
UIScrollView* currentScrollView;
for (UIView* subView in self.myWebView.subviews) {
if ([subView isKindOfClass:[UIScrollView class]]) {
currentScrollView = (UIScrollView*)subView;
currentScrollView.delegate = self;
}
}
}
It's working. You can also use it to call [currentScrollView setContentOffset:offSet animated:YES]; The only problem may be not to pass Apple code checking. I don't know yet since I'm still in coding phase.
[UPDATE] The app with this code is in the app store for 4 months now and used by 40 000 users. I didn't have any trouble [UPDATE]
You can use the following methods to solve your problem.
For getting the pageOffset:
int pageYOffset = [[webViewObj stringByEvaluatingJavaScriptFromString:#"window.pageYOffset"] intValue];
For getting the total scroll height of a webpage:
int scrollHeight = [[webViewObj stringByEvaluatingJavaScriptFromString:#"document.documentElement.scrollHeight"] intValue];
For scrolling the webpage to a particular offset:
[webViewObj stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:#"document.body.scrollTop = %d",scrollHeight ]];
I made a modification to detect the class with isKindOfClass. Works - but may have issues with Apple code checking as stated above.
UIScrollView* currentScrollView;
for (UIView* subView in terms.subviews) {
if ([subView isKindOfClass:[UIScrollView class]]) {
NSLog(#"found scroll view");
currentScrollView = (UIScrollView *)subView;
currentScrollView.delegate = self;
}
}
Old thread, I know -
As of iOS 5.0 you can use
myAccountWebView.scrollview
to access content size and offset.
There is a scrolling view in the UIWebView, but it a) isn't a UIScrollView, and b) is something Apple considers a private implementation detail (and you should too). I only really have two suggestions:
File a bug with Apple asking them to expose more of the infrastructure of the web view, or at least add some more delegate methods by which we can be notified of these sorts of events.
Add some JavaScript code to your page that listens from scroll events, and notifies your app of them.
The basic foundation of #2 is to load a fake URL, and have your web view delegate process (and abort!) that load. (This question has come up a few times here on Stack Overflow.)
UPDATE:
As of iOS 5, there is now a public scrollView property on UIWebView that you can use to customize scrolling behavior. The exact view hierarchy of the web view remains an undocumented implementation detail, but this gives you a sanctioned way to access this piece of it.
It's a good question. UIWebView is not a subclass of UIScrollView, although I can see why one might think it is. That means using the UIScrollViewDelegate methods is not an option to do what you want, and the UIWebViewDelegate protocol does not respond to those scrolling event type of messages. I don't think there's an easy way to detect scrolling events in a web view.
I tired the delegate method and found it prevented the view from scrolling when the keyboard was shown. I found that by adding an observer you do not override the current delegate and will prevent you from effecting the webview performance.
for (UIView* subView in myAccountWebView.subviews) {
if ([subView isKindOfClass:[UIScrollView class]])
{
NSLog(#"found scroll view");
[((UIScrollView*)subView) addObserver:self forKeyPath:#"contentOffset" options:NSKeyValueObservingOptionNew context:nil];
}
}
Using this method to hide the status bar:
[[UIApplication sharedApplication] setStatusBarHidden:YES animated:YES];
When setting "hidden" back to NO, the tap-to-scroll-to-top (in UIWebView, UITableView, whatever) doesn't work any more, and requires a restart of the app to get the functionality back.
Is this a bug (I filed a rdar anyhow) or have I missed a step? Should I perhaps expect this behavior since the statusBar "loses touch" somehow with the respective view?
You could try setting the ScrollsToTop property to true again after re-showing it:
[currentView setScrollsToTop:YES];
If that's not working, are you definitely only showing one view? If there is more than one scrolling view a scrollViewDidScrollToTop message is ignored...
In iOS 5.0 you can access the scrollview property of the UIWebView
webView.scrollView.scrollsToTop = YES;
The following fix by Alex worked for me. Thanks!
((UIScrollView *)[[webView subviews] objectAtIndex:0]).scrollsToTop = NO;
Being in a hurry this fix worked great, however given more time I might've subclassed the UIWebView and accessed the protected UIScrollView member directly.
The worry I have with Alex' method is that it assumes that UIScrollView is at index zero of the subviews (encapsulation allows private members to change). Which suggests another solution still:
for (UIView* v in [webView subviews])
{
if ([v isKindOfClass:[UIScrollView class]])
{
(UIScrollView *)v.scrollsToTop = NO;
}
}
I was having a similar problem where the scroll-to-top functionality was lost. Turns out this will only work when you have only one active view at a time (within the same scroll view). In my case I had a table view and another view which would fade in/out. Adding a removeFromSuperview at the end of the animation did the trick.
The answer was in the UIScrollView.h file comments:
/*
this is for the scroll to top gesture. by default, a single scroll visible scroll view with this flag set will get the call. if there is more than one visible with this
flag set or the delegeat method returns NO, the view isn't scrolled
*/
#property(nonatomic) BOOL scrollsToTop; // default is YES. if set, special gesture will scroll to top of view after consulting delegate
You can use the following code to have the UIWebView ignore scrollToTop without the extra UIScrollView:
((UIScrollView *)[[webView valueForKey:#"_internal"] valueForKey:#"scroller"]).scrollsToTop = NO;
I had a similar problem after playing a Youtube video within my app. scrollsToTop was still set to YES but tapping the status bar had no effect.
I finally realised that my app window was no longer the key window. After adding the following line to a UIWindow subclass (which I already had for other reasons) everything worked as it should again:
if (![self isKeyWindow]) [self makeKeyWindow];
I just ran across a similar behavior in the app I'm currently working on. In its case, if you load a YouTube video from within a UIWebView, scroll to top stops working for the rest of the application's life cycle. I kind of assume this might happen after loading the movie player as well, but haven't confirmed. That functionality has been around a lot longer and probably has fewer bugs.
When there are multiple scrollview, you can also set scrollUpToTop to NO for the others scrollview. cf:
setScrollsToTop with multiple UIScrollView classes and/or subclasses(UITableView)
I want to add my case, I add an UIWebView on an UIScrollView, as h4xxr had answered on the top:
If there is more than one scrolling view a scrollViewDidScrollToTop message is ignored
So, I get a simply way to make it work on webView: just set the scrollView·s scrollsToTop property false.
And when tap the status bar, it won`t got intercepted by the scrollView, and the webView scrolls to the top!
UIScrollView *scrollView = [[UIScrollView alloc] init];
scrollView.frame = self.view.bounds;
scrollView.scrollsToTop = false; //igore scrollView`s scrollsToTop
[self.view addSubview:scrollView];
UIWebView *webView = [[UIWebView alloc] init];
webView.frame = scrollView.bounds;
[scrollView addSubview:webView];