I have 2 WebViews in my application. one is loading a youtube video and the other is loading an events calendar. I want to show a custom 'Loading' image until the data from the web views are done loading.
I am trying
while([youtubeView isLoading]){
NSLog(#"youtubeVideo is loading");
[loadingImage setHidden:NO];
}
[loadingImage setHidden:YES];
In viewDidLoad but it doesn't work.
Whats the best way to accomplish what I am trying to achieve?
Cheers, Beers on me.
Use below method of UIWebViewDelegate. It get called once webView finish loading.
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
if(youtubeView isEqual:webView)
{
loadingImage.hidden = YES;
}
}
Also note that your class need to conform to UIWebViewDelegate and both your webviews should set delegate equal to object of that class.
#interface YourViewController : UIViewController <UIWebViewDelegate>
{
UIWebView *youtubeView;
}
#end
inside method where you create UIWebView youtubeView
youtubeView.delegate = self;
Beer ?
Related
I have implemented AdMob & everything seems to work,
But i wonderd, how can i put the banner in all of my view controllers?
For now, i have the banner only on the RootViewController.
I have total of 4 view controllers.
Thanks.
What you want here is a GADBannerView singleton of sorts. You can probably create a wrapping class to act as a singleton for your adView, so something like:
#interface GADMasterViewController : UIViewController {
GADBannerView *adBanner_;
BOOL didCloseWebsiteView_;
BOOL isLoaded_;
id currentDelegate_;
}
And just make sure that GADMasterViewController always returns a singleton:
+(GADMasterViewController *)singleton {
static dispatch_once_t pred;
static GADMasterViewController *shared;
// Will only be run once, the first time this is called
dispatch_once(&pred, ^{
shared = [[GADMasterViewController alloc] init];
});
return shared;
}
Have a method which resets the current view controller that's holding on to the adView:
-(void)resetAdView:(UIViewController *)rootViewController {
// Always keep track of currentDelegate for notification forwarding
currentDelegate_ = rootViewController;
// Ad already requested, simply add it into the view
if (isLoaded_) {
[rootViewController.view addSubview:adBanner_];
} else {
adBanner_.delegate = self;
adBanner_.rootViewController = rootViewController;
adBanner_.adUnitID = kSampleAdUnitID;
GADRequest *request = [GADRequest request];
[adBanner_ loadRequest:request];
[rootViewController.view addSubview:adBanner_];
isLoaded_ = YES;
}
}
Then displaying your ad is just a matter of:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
shared = [GADMasterViewController singleton];
[shared resetAdView:self];
}
You probably need to set up a delegate to forward notifications as well since the AdMob SDK doesn't act well to delegates changing on it in the middle of a request.
You can find a blog post about this here.
I don't know how adMob works but like everything else you can create a BaseViewController in which you can add your adMob(in the viewDidLoad method) and then all the other viewControllers can subClass this BaseViewController. just call [super viewDidLoad]; in the viewDidLoad methods of your viewControllers and you will have it...
hoping this sorts your problem... :)
In my app I dragged a View from the library of the interface builder and linked it to the AppDelegate.
my question is "can I add UIWebView inside the View ?"
and if make a special class (UIView class) for the view which method behaves like viewDidload ?
Yes you can add a UIWebView inside the View.
[UIWebView *aWebView =[[UIWebView alloc] initWithFrame:CGRectMake(x,y,width,height)]; aWebView.delegate=self;
[self.view addSubview:aWebView];
[aWebView release];
In the above code you set the delegate of the WebView as self. So you can use the delegate methods of UIWebView like
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
- (void)webViewDidFinishLoad:(UIWebView *)webView
Refer this link for more details.
http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UIWebViewDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intf/UIWebViewDelegate
Yes you can simply use -
In your h file add
#interface YourView:UIView<UIWebViewDelegate>{
in your m file add
CGRect frame = CGRectMake(0,0,200,200);
UIWebView *webView =[[UIWebView alloc] initWithFrame:frame)];
webView.delegate = self;
[self addSubview:webView];
CGRect rect=CGRectMake(x,y,width,height) ;
UIWebView *webView1 =[[UIWebView alloc] initWithFrame:rect)];
webView1.delegate=self;
[self.view addSubview:webView1];
[webView1 release];
If you view's outlet is named myView:
.h file
#interface myViewController:UIViewController <UIWebViewDelegate> {
IBOutlet UIView *myView;
}
.m file
UIWebView *,myWebView = [[UIWebView alloc] initWithFrame:CGRectMake(0,0,myView.frame.size.width,myView.frame.size.height)];
myWebView.delegate = self;
[myView addSubView:myWebView];
It's not necissary to create another subclass to listen for deleagte methods of your view, i would now treat your UIView as a UIWebView and thus use UIWebView's delegate methods, like so:
- (void)webViewDidStartLoad:(UIWebView *)webView {
NSLog(#"started loading");
}
more delegate methods can be found here in the documentation. You could also use NSNotificationCenter to listen for your own events application wide if you wish to fire something in a different class when the UIWebView is loaded.
I'm relatively new to Objective-C and coding. I've tried doing a little dev on my own but have now become stuck on what is probably a rookie error.
I've created a tab bar controller with 5 views, one such view is a UIWebView. I've got the Webview working and it loads, but when I select a different tab, the app crashes. Please find my code below and any help would be appreciated!
#import <UIKit/UIKit.h>
#interface LiveViewController : UIViewController {
IBOutlet UIWebView *liveView;
}
#property (nonatomic, retain) UIWebView *liveView;
#end
#import "LiveViewController.h"
#implementation LiveViewController
#synthesize liveView;
// The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
/*
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization.
}
return self;
}
*/
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[self.liveView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.britishseapower.co.uk/live/"]]];
[super viewDidLoad];
}
- (void)webViewDidStartLoad:(UIWebView *)liveView
{
// starting the load, show the activity indicator in the status bar
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
}
- (void)webViewDidFinishLoad:(UIWebView *)liveView
{
// finished loading, hide the activity indicator in the status bar
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (void)liveView:(UIWebView *)liveView didFailLoadWithError:(NSError *)error
{
// load error, hide the activity indicator in the status bar
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
// report the error inside the webview
NSString* errorString = [NSString stringWithFormat:
#"<html><center><font size=+5 color='red'>An error occurred:<br>%#</font></center></html>",
error.localizedDescription];
[self.liveView loadHTMLString:errorString baseURL:nil];
}
- (void)viewWillDisappear:(BOOL)animated
{
if ( [self.liveView loading] ) {
[self.liveView stopLoading];
}
self.liveView.delegate = nil; // disconnect the delegate as the webview is hidden
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (void)dealloc {
[liveView release];
[UIWebView release];
[LiveViewController release];
[super dealloc];
}
#end
Many thanks,
Ryan
[UIWebView release]; [LiveViewController release];
This is what make your app crash.
It's not valid to send a release message to a class itself.
What you've done with [liveView release]; is enough (with the call to [super dealloc];.)
You should also set the delegate to nil in the dealloc method as in the viewWillDisappear method self.liveView.delegate = nil;. This way you're sure to avoid any further message sent to the LiveViewController from the UIWebView.
You should read a bit more of documentation on Objective-C to better understand how it works.
Not sure if this is related but I noticed that you aren't setting yourself as the delegate anywhere in code which means that it must be connected in Interface Builder. Now when the view disappears, you are breaking that connection, but if the view were to re-appear and wasn't previously unloaded that connection will remain broken.
One of the most common reasons why an app may crash is to refer to or send a message to an object that has been already released from the memory. And this type of bug can be easily located using NSZombieEnabled and looking into the console message. So if you haven't already tried that, that's the first thing you must do.
The problem could be in LiveViewController but could be in the other view controllers as well. I wouldn't believe the problem is 100% in LiveViewController because the view controller wouldn't try releasing its view when the view is not shown unless it gets a memory warning. And you run the app using the simulator, it's unlikely it will have a memory warning unless you simulate one.
You would probably know that a view controller never create a view unless the view is used by an object. One of the other view controllers may have a silly bug in its view loading process which causes a crash. Or, you might have released another view controller by mistake. Make 100% sure that the other view controllers have no problem showing their views on their own, when you keep changing between their views (without showing LiveViewController).
So what I would do is to try NSZombieEnabled and check if it accesses a released object, and if it does, what the object is. Also, I will make a double check that the problem is related to LiveViewController. If it doesn't help I would log a message when LiveViewController and its liveView is deallocated (for liveView you need to subclass it). Because delegate property almost always does not retain an object, if the LiveViewController object is released (which shouldn't happen) and liveView still has a reference to it in the delegate property it will make a crash.
Crashes like this are almost always related to releasing an object that has already been released and deallocated.
Let XCode help you find the error. In XCode 4:
- In the toolbar, select the scheme list, and select 'Edit Scheme'
- Select the 'Run Your.app' in the list on the left.
- Under 'Environment Variables', add the following name/value pairs in the appropriate columns:
CFZombieLevel 3
NSZombieEnabled YES
Now when debug your app, you will get a message telling when -release is called on an object that already has a -retainCount of zero. Now you have a good clue to start your investigation.
Note that these flags prevent objects from being deallocated, so it is best to turn them on as needed to prevent out of memory errors.
I've opted to use UIWebView so I can control the layout of text I've got contained in a local html document in my bundle. I want the text to display within a UIWebView I've got contained within my view. So the text isn't the whole view, just part of it.
Everything runs fine, but when the web page loads I get a blank screen for a second before the text appears. This looks really bad. can anyone give me an example of how to stop this happening? I'm assuming I have to somehow hide the web view until it has fully loaded? Could someone one tell me how to do this?
At the moment I'm calling my code through the viewDidLoad like this:
[myUIWebView loadRequest: [NSURLRequest requestWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle]pathForResource:#"localwebpage" ofType:#"html"] isDirectory:NO]]];
Any help is much appreciated. I've read round a few forums and not seen a good answer to this question, and it seems like it recurs a lot as an issue for beginners like myself.
Thanks for taking the time to read this post!
UPDATED info
Thanks for your response. The suggestions below solves the problem but creates a new one for me as now when my view loads it is totally hidden until I click on my toggle switch. to understand this it's maybe most helpful if I post all my code. Before this though let me explain the setup of my view. I've got a standard view within which I've also got two web views, one on top of the other. each web view contains different text with different styling. the user flicks between views using a toggle switch, which hides/reveals the web views. I'm using the web views because I want to control the style/layout of the text. Below is my full .m code, I can't figure out where it's going wrong. My web views are called oxford & harvard I'm sure its something to do with how/when I'm hiding/revealing views. I've played around with this but can't seem to get it right. Maybe my approach is wrong. A bit of advice ironing this out would be really appreciated:
#implementation ReferenceViewController
#synthesize oxford;
#synthesize harvard;
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
[oxford loadRequest: [NSURLRequest requestWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle]pathForResource:#"Oxford" ofType:#"html"] isDirectory:NO]]];
[harvard loadRequest: [NSURLRequest requestWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle]pathForResource:#"Harvard" ofType:#"html"] isDirectory:NO]]];
[oxford setHidden:YES];
[harvard setHidden:YES];
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
if([webView hidden]) {
[oxford setHidden:NO];
[harvard setHidden:NO];
}
}
//Toggle controls for toggle switch in UIView to swap between webviews
- (IBAction)toggleControls:(id)sender {
if ([sender selectedSegmentIndex] == kSwitchesSegmentIndex)
{
oxford.hidden = NO;
harvard.hidden = YES;
}
else
{
oxford.hidden = YES;
harvard.hidden = NO;
}
}
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
[oxford release];
[harvard release];
}
#end
Sure, in your UIViewController's designated initializer, set the hidden property of the UIWebView instance to YES:
[webView setHidden:YES];
Then, implement the UIWebViewDelegate method - (void)webViewDidFinishLoad:, and perform an if check inside the method like this:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
if([webView hidden]) {
[webView setHidden:NO];
}
}
Also, don't forget to specify that your class conforms to the UIWebViewDelegate protocol:
#interface YourViewController : UIViewController <UIWebViewDelegate> {...}
I want to put a big spinner along with a "Loading message..." or a gif image, when UIWebView loads its contents so it won't just show a blank view. How should I do it?
implement UIWebview's delegate method put this code in it
- (void)webViewDidStartLoad:(UIWebView *)webView {
[activityIndicator startAnimating];
myLabel.hidden = FALSE;
}
- (void)webViewDidFinishLoad:(UIWebView *)webView {
[activityIndicator stopAnimating];
myLabel.hidden = TRUE;
}
set ActivityIndicater's Hidden when stop property to TRUE
Implement the UIWebView Delegate as outlined in Mihir's answer above but don't forget to assign the delegate otherwise the delegate methods will not be triggered
For example In ViewDidLoad you should add:
self.myWebView.delegate = self;