I'm using Page Control example from Apple. I want to be able to scroll horizontally to certain page and get the sound automatically play when viewing that page? And then sound stop when viewing the other page?
So, for example. On page 1, i have some texts. When i go to the next page which is on page 2, i want sound to be automatically play and stop when i go to page 3.
I'm planning to use If statements (since it's not that many pages) to determine which page will get the sound.
My question is simple. How do you get the sound play automatically when viewing certain page?
By the way, I'm planning to use System Sound.
I know how to play the sound using button. But how do you get it automatically - start when certain page appear and stop when moving to the next page.
Thank you in advance!
Edited:
I put in this code in ViewDidLoad but the sound played on sooner before it reach the page intended:
// Set the label and background color when the view has finished loading.
- (void)viewDidLoad {
pageNumberLabel.text = [NSString stringWithFormat:#"Page %d", pageNumber + 1];
self.view.backgroundColor = [MyViewController pageControlColorWithIndex:pageNumber];
if (pageNumber == 3) {
NSString *path = [[NSBundle mainBundle] pathForResource:#"crunch" ofType:#"wav"];
SystemSoundID soundID;
AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:path], &soundID);
AudioServicesPlaySystemSound(soundID);
}
}
Why cant you make the sound go off when your desired viewControllers view goes on screen? You know when it goes on screen from the scrollViewDidScroll method and loadPage method (in the Page Control example). By looking at the methods in there you should be able to identify when you need to play the sound (because the specific view has come on the screen) and play it. Another approach would be to subclass UIViewController with something like UISoundViewController and have it play the sound on viewDidLoad.
-viewDidLoad is called once and only once* when the view controller's view property is loaded. You only add stuff that is called once and only once in this method.
Playing sound clearly isn't a once-and-only-once event. Put those into -viewDidAppear:.
*: Unless the view controller is deallocated.
Related
I'm running into a strange issue, I hope someone can help.
In my iOS app I create a video with a custom soundtrack using MutableComposition by combining a video from the user's photo library and an audio file from the app bundle. I then use an AVPlayer and AVPlayerItem to play the video back to the user using a custom video player I made.
Each time a new composition is created, the assets, the player and the composition are cleared, released and it basically starts from a clean, init state.
All works fine, until after exactly 4 successful videos created this way every other attempt to create the player fails with error Cannot Decode. It does not matter if its the same video I'm recreating, has no relation to the size/length of the video or the audio file it simply always fails exactly on the fifth attempt, like clockwork. Once it fails, it will then always fail!
This is weird, because it just decoded the same video four times with no problem, so all of a sudden it fails? So, if anyone has a clue, please let me know.
Ok everyone, I have the answer to this straight from Apple. I used one of my developer TSI lifelines to ask the question, and I'll summarize the response.
There is a limit on the number of concurrent video players that AVFoundation will allow. It is due to the limitations of iOS hardware. The limit for current devices is 4 players. If you create a 5th player, you will get the "cannot decode" error. It is not a limit on the number of instances of AVPlayer, or AVPlayerItem. Rather,it is the association of AVPlayerItem with an AVPlayer which creates a "render pipeline", and you are limited to 4 of these. For example, this causes a new render pipeline:
AVPlayer *player = [AVPlayer playerWithPlayerItem:somePlayerItem];
// assuming the AVPlayerItem is ready to go with an AVAsset that has been loaded
I was also warned that you cannot assume that you will have 4 pipelines available to you. Another App may be using one or more. Indeed, I have seen this happen on an iPad, but it was not clear which app was using a pipeline.
So, there you go, it was totally undocumented, but that is the story.
I ran into the same error message after creating 4 AVPlayer instances, the fix in my case wasn't exactly the same though. Perhaps this will help anyone else who comes across this problem.
What I eventually found is that the AVPlayers were not being released when I had thought they were. In my case I was pushing my AVPlayer View Controller onto a Navigation Controller. Even though I was only creating one AVPlayer instance at a time, when the View Controllers are popped off a nav controller they were not being released immediately. It was then very easy for me to reach 4 AVPlayer instances before the old View Controllers were cleaned up.
It wasn't until I made sure that the previous players were released that this problem went away. To be complete I released the AVPlayerItem, AVPlayer and set the player on the AVPlayerLayer to nil before releasing.
I have to wonder if there is some limit on AVPlayer instances, unintentional or not. A related bit of info from the docs:
https://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/02_Playback.html
"Multiple player layers: You can create arbitrarily many AVPlayerLayer objects from a single AVPlayer instance, but only the most-recently-created such layer will display any video content on-screen."
This one was absolutely killing me until I figured it out, picking up clues from this thread and a few others. The biggest single problem in my code was that I was instantiating my video player controller every time I wanted to play a video. Now, it gets instantiated once in the primary controller (in this case, my DetailViewContoller):
#interface DetailViewController () {
VideoPlayerViewController *videoPlayerViewController;
}
- (void) viewDidLoad
{
[super viewDidLoad];
videoPlayerViewController = [[VideoPlayerViewController alloc] initWithNibName: nil bundle: nil];
}
When I want to show a video, I call my DetailViewController's startVideoPlayback method:
- (void) startVideoPlayback: (NSString *)videoUID
{
videoPlayerViewController.videoUID = videoUID;
[self presentModalViewController: videoPlayerViewController animated: YES];
}
(NOTE: I'm passing it 'videoUID' -- a unique identified that was used to create the video in another part of the app.)
In the VideoPlayerViewController (which is largely cribbed from Apple's AVPlayerDemo sample), the one-time screen setup (initializing the AVPlayer, setting up the toolbar, etc.) is done in viewDidLoad -- which now only get's called once, and all per-video setup gets done within viewWillAppear, which then calls prepareToPlay:
- (void) prepareToPlay
{
[self initScrubberTimer];
[self syncPlayPauseButtons];
[self syncScrubber];
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
//*** Retrieve and play video at associated with this videoUID
NSString *destinationPath = [documentsDirectory stringByAppendingFormat: #"/%#.mov", videoUID];
if ([self fileExists: destinationPath]) {
//*** Show the activity indicator spinny thing
[pleaseWait startAnimating];
[self setURL: [NSURL fileURLWithPath: destinationPath]];
//*** Get things going with the first video in this session
if (isFirst) {
isFirst = NO;
//*** Subseqeunt videos replace the first one
} else {
[self.mPlayer replaceCurrentItemWithPlayerItem: [AVPlayerItem playerItemWithURL: [NSURL fileURLWithPath: destinationPath]]];
}
}
}
OK, I figured out a solution, I hope this is helpful to anyone who may stumble on something similar to this problem.
The solution in my case was to initialize the asset for the AVPlayer and the AVPlayerItem on the main thread and make sure I don't create the actual AVPlayerLayer before the playerItem and the player objects return with status "ReadyToPlay".
This proved to be tricky to isolate and I still don't know why it worked the first 4 times and then failed consistently on the 5th time.
Till, I couldn't really include the code, it wasn't a matter of one line or even a few functions. It was a complex problem that I couldn't isolate to begin with. Thanks for the comments though.
It seems like that issue can be caused by any decoding tasks, not only actual players.
I randomly had this problem when I implemented a background task to extract frames from currently playing videos with generateCGImagesAsynchronously
I need to display 4 videos on screen and a race condition would sometime cause the frame extraction to start before the video started playing and I would wait for isReadyForDisplay forever.
Not sure what a good recover strategy is if you can't avoid the condition in the first place, I would probably try to replaceCurrentItem
I have never use youtube api in iPhone ...I tried to use GData but was missed in some steps here are link ans tutorial ....So never implemented it...
Due to which i used RSS feed and load it on tableView ...
and when user click on any row then the actual webPage opens in WebView and user have to click on the video to run it....
But now i don't want this ....
Can anyone provide me a better solution....
Thanks...
As I have given a brief answer here
I am explaining it in detail:
Put a button of same size and without any background image over your webview.
When the user presses this button open a new modal view with only a full screen size webview in it.
Pass the same html string to load the webview (that you were passing in your smaller webview).
Pass the touches programmatically to the webview like:
– (void) touchTheWebViewProgrammatically{
for(UIView* vw in [webView subviews]){
if([vw isKindOfClass:[UIButton Class]])
[vw sendActionsForControlEvents:UIControlEventAllEvents];
}
}
In my app i want to put my website's url on home screen and on clicking on it i want it to be open as a WebView.
How should i go for this.
Thanks,
Previous commenter is incorrect. You can open any hyperlink either externally with Safari or internally with a UIWebView.
Add a UIWebViewController to your project. Then, instantiate an instance of a the UIWebViewController that will be shown inside your app--you'll do this by declaring a property & synthesizing it within your main view controller (which will need to be declared as a UIWebViewDelegate), such as:
#interface MyMainViewController: UIViewController <UIWebViewDelegate> {
// Your implementation code here
}
When a user taps the button (assuming you make it a button, rather than just a text hyperlink), you instruct your app to add the UIWebView to the view stack, loading the correct link. You'll want to either do this within a modal view or within a navigation stack so your users can get back out of the web view, of course.
In your MyMainViewController implementation file, something like this:
-(void) showWebView {
// NOTE: I have not tested this, just prototyping
// off the top of my head
UIWebView *myWebView = [[UIWebView alloc] init];
myWebView.delegate = self;
NSURL *homeUrl = [[NSURL alloc] initWithString:#"http://example.com"];
NSURLRequest *homeRequest = [NSURLRequest requestWithURL:homeURL];
[myWebView loadRequest:homeRequest];
[self.presentModalViewController: myWebView animated:YES];
// Don't forget to release objects when you're done
[myWebView release]; // etc.
}
Now, this is off the top of my head from what I know and have done. But I hope you get the general idea. I offer no warranty of any kind here, but do guarantee this is entirely possible with minimal headache. If you get stuck, check out the developer references for UIWebView. Apple's docs are top-notch & show great examples to get you up and running quickly.
Best.
In one of my apps I reuse a webview. Each time the user enters a certain view on reload cached data to the webview using the method :-
- (void)loadData:(NSData *)data MIMEType:(NSString *)MIMEType textEncodingName:(NSString *)encodingName baseURL:(NSURL *)baseURL
and I wait for the callback call
- (void) webViewDidFinishLoad:(UIWebView *)webView.
In the mean time I hide the webview and show a 'loading' label.
Only when I receive webViewDidFinishLoad do I show the webview.
Many times what happens I see the previous data that was loaded to the webview for a brief second before the new data I loaded kicks in.
I already added a delay of 0.2 seconds before showing the webview but it didn't help.
Instead of solving this by adding more time to the delay does anyone know how to solve this issue or maybe clear old data from a webview without release and allocating it every time?
Thanks malaki1974, in my case I wasn't using a modal view.
When I sat with an Apple engineer on WWDC 2010 and asked him this question his answer was simply: "Don't reuse UIWebViews, that's not how they were ment to be used."
Since then I make sure to calls this set of lines before allocating a new UIWebView
[self.myWebView removeFromSuperview];
self.myWebView.delegate = nil;
[self.myWebView stopLoading];
[self.myWebView release];
That solved the issue.
Clear the contents of the webview before you try to load new content
[self loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:#"about:blank"]]];
First, the UIWebView renders it contents in a background thread. Even when you receive webViewDidFinishLoad: it might not be completely done. Specially if it is an ajax-intense page that comes from the network.
You say you are hiding the view. I wonder if that means that the webview delays its drawing completely. What you could try is to move the UIWebView offscreen or obscure it with another view. Maybe that will change it's drawing behaviour.
If you do not need an interactive UIWebView then you can also consider to do it completely offscreen in a separate UIWindow and then create an image from that UIWebView's layer.
That's what I do, and it works:
[_webView stringByEvaluatingJavaScriptFromString:#"document.open();document.close();"];
Try loading a local file that is blank or has a loading graphic when you hide it, rather than just loading new content when you show it. Since the file is local it will be quick and even if the new page takes a while to load it will have either blank or loading expected behavior.
If you got controll over the html. You can communicate back to objective-c when the document is ready. Like so in jQuery:
function messageNative (name, string) {
var iframe = document.createElement("IFRAME");
iframe.setAttribute("src", "appscheme://" + name + "/" + string);
document.documentElement.appendChild(iframe);
iframe.parentNode.removeChild(iframe);
iframe = null;
}
$(function() {
messageNative('webview', 'ready');
});
And then in UIWebView's delegate method webView:shouldStartLoadWithRequest:navigationType: wait for the request with url equal to "appscheme://webview/ready". Then you should know: the document is loaded and ready for display. Then all that is missing is a simple fade-in or something like that :)
i put a movie when my application will lunch . just like gameloft games .
so when application has lunched , movie plays fine but before the move plays .. my FirstViewController xib file show first then moview start to play ! why ?
here is my code :
- (void)applicationDidFinishLaunching:(UIApplication *)application {
NSBundle *bundle = [NSBundle mainBundle];
NSString *moviePath = [bundle pathForResource:#"movie" ofType:#"m4v"];
NSURL *movieURL = [[NSURL fileURLWithPath:moviePath] retain];
MPMoviePlayerController *IntroMovie = [[MPMoviePlayerController alloc] initWithContentURL:movieURL];
IntroMovie.movieControlMode = MPMovieControlModeHidden;
[IntroMovie play];
}
Your question is a little unclear, but what I think you are asking is why your movie is not playing when the application launches before the user sees the controls and items in your XIB file. If this is correct, then this is the normal behavior as typically the application will launch and only then call the function you have (applicationDidFinishLaunching). There is no guarantee that you will get that function called before the controls have loaded and are viewable on the screen all the time.
It is bad form to start you application with a movie, but if you want to then you have to deal with the fact that there will potentially be a default image or even your controls that you put in your XIB file.
One way to start with a movie, is that you must hide or delete everything in the XIB file so the screen will appear blank when the application loads. Then, when you application calls the applicationDidFinishLaunching function the user will not have seen your application and the first thing they will see is the movie. When the movie is finished playing, you will need to have a notification listener instruct your application to show the controls for your application or switch to another XIB file that has the app controls within it.
I hope this helps.