I've been doing the tutorials in the Big Nerd Ranch Iphone development book and ran into an issue I can't solve or find an answer for.
The App (Hypnosister) basically just draws a bunch of concentric circles and places some text on the screen using the DrawRect method. I got that to work and I was able to add scrolling ot the view but can't add the ability zoom. I've checked my code 100 times and can't figure it out. I think they used an earlier version of the OS and I am using 4.2. Did something change? Can you find the issue?
Here is the relevant code:
#interface HypnosisterAppDelegate : NSObject <UIApplicationDelegate,
UIScrollViewDelegate>
{
UIWindow *window;
HypnosisView *view;
}
and this goes in the application didFinishLaunchingWithOptions part:
[[UIApplication sharedApplication]
setStatusBarHidden:YES withAnimation:UIStatusBarAnimationFade];
and method gets called after that method closes:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return view;
}
HypnosisView is a UIView class that does the drawing. Thanks for the help.
Just downloaded the examples for the book from the Big Nerd Ranch website and it works fine on the simulator under 1OS 4.3. Did you add these lines of code to didFinishLaunchingWithOptions:
// Enable zooming
[scrollView setMinimumZoomScale:0.5];
[scrollView setMaximumZoomScale:5];
[scrollView setDelegate:self];
This is only possible problem I can think of based on the code you've shown.
Related
I am trying to create a small game for the iPhone with images and I want to them to zoom in when the player is pinching on the screen. I have seen the tutorials with one UIImageView. However, now that I am using multiple UIImageViews, things do not work OK.
I put them in an UIView and I am trying to zoom the UIView. However things are not scaling inside the screen when I run the simulator.
I use the following code
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return containerView; //containerView is the UIView containing all the UIIMageviews
}
-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
{
[containerView setTransform:CGAffineTransformIdentity];
containerView.contentScaleFactor = scale;
}
Any suggestions?
Thanx!
Have a look at the ScrollViewSuite sample on the apple developer site, that has a working example of what I think you're trying to do.
(I think I got the name right, the developer site is down for updates just now so I can't give you a link.)
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];
}
}
I would like to have an OpenGL view with an utility application.
What I do:
I create an OpenGL ES application template and a Utility Application template.
I copy the files EAGLView.m and h, and the five ESrenderer. files from the Opengl project to the utility project.
I copy these lines from the OpenGl project to the Utility project: (in utilityAppDelegate.m)
- (void)applicationDidFinishLaunching:(UIApplication *)application {
...
[glView startAnimation];
}
- (void) applicationWillResignActive:(UIApplication *)application
{
[glView stopAnimation];
}
- (void) applicationDidBecomeActive:(UIApplication *)application
{
[glView startAnimation];
}
- (void)applicationWillTerminate:(UIApplication *)application
{
[glView stopAnimation];
}
- (void)dealloc {
...
[glView release];
...
}
And in the utilityAppDelegate.h I add:
#class EAGLView;
EAGLView *glView;
#property (nonatomic, retain) IBOutlet EAGLView *glView;
I go to the view's identity inspector, and change the class identity to EAGLview.
I open the mainview.xib and mainwindow.xib and drag the app_delegate from the mainwindow.xib, to be able to connect the glView outlet to the view.
(Don't know if this is the way to do it, but that's the only way I could connect the glView variable to the view)
When I build and run, the multi colored square show up on the screen, but it does not animate!
When I debug, the glView variable is 0 in applicationDidFinishLaunching, and the startAnimation is not called. I suspect this has something to to with the way the outlet is connected to the view? Probably not connected. :-)
The mistake is probably obvious, but I have only been 5 weeks on this platform.
What is missing? What have I done wrong?
Thank you!
I don't know if you've provided enough information to tell exactly what's going wrong in your case. However, I'd suggest that you look at the source code for my iPhone application Molecules.
While it is a little more complex, the application is based on those two templates. It uses an OpenGL ES main view (where a 3-D molecular rendering is presented), and a table view / navigation controller on the flipside (for switching molecular structures, examining their properties, and downloading new ones). You could review that example to see what you might be doing wrong, or even just replace my rendering and view code with your own.
I got the solution in another forum:
http://iphonedevbook.com/forum/viewtopic.php?f=25&t=3192&sid=9cf79468b81a8fd6c9d9020958d33388
Basically, just add the glView outlet to the MainViewController instead of the AppDelegate.
I would like to hide the native scrollbar / scroller that appears when you are scrolling a UIWebView, but still keep the scrolling functionality intact. Is this possible?
Thanks in advance,
William
It seems this question needs an updated answer:
You can directly access the scroll view associated with the web view. (read-only)
in iOS 5.0 an above.
I don't think developers should be supporting anything prior to iOS 5.0 unless in exceptional circumstances.
From the Apple developer docs.
#property(nonatomic, readonly, retain) UIScrollView *scrollView
Discussion
Your application can access the scroll view if it wants to customize the scrolling behavior of the web view.
Availability
Available in iOS 5.0 and later.
Declared In
UIWebView.h
Now you can directly write something like this:
webView.scrollView.showsHorizontalScrollIndicator = NO;
webView.scrollView.showsVerticalScrollIndicator = NO;
No need to go to the subviews of the webView.
UIWebView doesn't inherit directly from UIScrollView, but you may be able to use UIScrollView properties on the UIWebView subview:
[(UIScrollView*)[webview.subviews objectAtIndex:0] setShowsHorizontalScrollIndicator:NO];
[(UIScrollView*)[webview.subviews objectAtIndex:0] setShowsVerticalScrollIndicator:NO];
No idea if this is acceptable, but it builds okay and I think it should work. Please report back if this works for you.
Also consider filing a feature request to Apple at bugreport.apple.com to add this property to a future UIWebView implementation.
Do it in that way:
for (id subview in self.myWebView.subviews) {
if ([[subview class] isSubclassOfClass: [UIScrollView class]]) {
((UIScrollView *)subview).bounces = NO;
((UIScrollView *)subview).showsVerticalScrollIndicator = NO;
((UIScrollView *)subview).showsHorizontalScrollIndicator = NO;
}
}
In Swift :
webView.scrollView.showsHorizontalScrollIndicator = false
webView.scrollView.showsVerticalScrollIndicator = false
If someone is looking for swift solution then below is the code for swift 3.0
yourWebView.scrollView.showsHorizontalScrollIndicator = false
yourWebView.scrollView.showsVerticalScrollIndicator = false
There's seems to be the beginning of an answer here :
http://discussions.apple.com/thread.jspa?threadID=1781730
If you disable user interaction, this seems to remove the scrollbar (this may be ok if the web page you display does not exceed the screen height).
A kind of javascript hack seems to be described also but I'm not mastering it :/ (you need to have access to the web page you try to display however, and this may not be your case....)