I have an iOS app built in XCode with Objective C mainly for iPads.
Basically I want to detect inside my application of AirPlay Mirroring is active, so mainly if the device is mirroring to another screen.
I searched all around stackoverflow but I couldn't find what I needed for this.
Some answers said that I have to use UIScreenDidConnectNotification for this.
The thing is that I have to call a function if the mirroring is active or when mirroring is activated, also when mirroring is stopped. So I think I need a listener for the mirroring changes.
Can you please help me?
I am relatively new to iOS development so please don't get upset if I may not know all things.:)
Some answers I've found :
https://stackoverflow.com/a/30319663/2866662
https://stackoverflow.com/a/22321926/2866662
https://stackoverflow.com/a/9027616/2866662
https://stackoverflow.com/a/10576262/2866662
Thanks!
Here's how you can call any function by subscribing to the notification, you can do it in viewDidLoad or where you find necessary:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(receiveAirPlayNotification:)
name: UIScreenDidConnectNotification
object:nil];
And to receive it:
- (void) receiveAirPlayNotification:(NSNotification *) notification
{
//Do whatever you want here, or call another function
NSLog(#"Received Notification - %#", notification);
[self doMyThing];
}
Related
I have an iOS app that only supports portrait when rotating the device the video captured by the RTCMTLVideoView rotates to landscape orientation, even when the rest of the UI stays in portrait.
So far the only solution that I found is to listen for the UIDeviceOrientationDidChangeNotification notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(orientationChanged:) name:UIDeviceOrientationDidChangeNotification object:nil];
and disabling it
- (void)orientationChanged:(NSNotification *)notification{
NSLog(#"orientation changed");
[[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
}
Is there any way to prevent this behaviour and keep it locked to portrait without this ugly workaround?
The problem in my case was that the video captured with the front camera was no mirrored.
I fixed the issue flipping the RTCMTLVideoView
self.myRTCMTLVideoView.transform = CGAffineTransformMakeScale(-1.0, 1.0)
The answer assumes usage of the latest stable M70 branch of WebRTC at the moment, as it's a moving target and API of its internal classes changes frequently.
Looks like RTCMTLVideoView is still work in progress and doesn't handle all scenarios appropriately. It has a rotationOverride property, but no documentation or example on how to use it. There is a similar question on Google Groups, which hasn't yet received attention, I encourage you to participate in discussion there, so WebRTC developers would know about that issue relevancy and made actions to fix it.
In the meantime, I suggest to switch to RTCEAGLVideoView which should work fine in that case.
I have a little bug. I'm developing an iOS App.
If i receive a call, my app stays open and the screen for my entering call appears on my app. I would like to close my app if i have a call.
How can i fix that?
Thanks,
J.
The green, in-call status bar is not a bug but a feature. You don't need to close the app when the call comes.
Instead, make sure your views are resized properly when the in-call status bar appears.
As Per Apple Human Interface guidelines
Never quit an iOS app programmatically because people tend to interpret this as a crash.
However, if external circumstances prevent your app from functioning as intended, you need
to tell your users about the situation and explain what they can do about it. Depending on
how severe the app malfunction is, you have two choices.
Display an attractive screen that describes the problem and suggests a correction. A
screen provides feedback that reassures users that there’s nothing wrong with your app. It
puts users in control, letting them decide whether they want to take corrective action and
continue using your app or press the Home button and open a different app
If only some of your app's features are unavailable, display either a screen or an alert
when people use the feature. Display the alert only when people try to access the feature
that isn’t functioning. `
But again you handle your app accordingly when call comes by using the following notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(incomingCall:) name:CTCallStateIncoming object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(callEnded:) name:CTCallStateDisconnected object:nil];
Srinivasan N's answer has the incorrect observer, you'll want to add this observer which will account for all scenarios: phone calls, Personal Hotspot, GPS/navigation, etc.
- (void)viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(adjustViews:) name:UIApplicationWillChangeStatusBarFrameNotification object:nil];
}
- (void)adjustViews:(NSNotification *)notification
{
NSValue *rectValue = [[notification userInfo] valueForKey:UIApplicationStatusBarFrameUserInfoKey];
CGRect newFrame;
[rectValue getValue:&newFrame];
NSLog(#"Changed frame to: Width: %f, Height: %f", newFrame.size.width, newFrame.size.height);
// Adjust your views here
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
Am using NSNotificationCenter in my iPhone App to post a notification
// I add an observer in didFinishLanchingWithOptions() in the AppDelegate
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(getData:) name:kNotif_GetData object:nil];
....
....
// then in another method, I post the notification
[[NSNotificationCenter defaultCenter] postNotificationName:kNotif_GetData object:nil];
....
One user says that this functionality (which is executed by getData()) is not working. so that might mean that the notification hasn't gotten fired. Any idea why this might happen? When I test it with different devices, it works perfect. The user uses iPhone5 and iOS7. Is there any more setting or any explicit user setting which is needed or which could turn this on/off?
No, notification centre is reliable.
"Not working" is not enough information to diagnose the problem. Get more information from the user or add more logging so that you know what is actually going on.
I am developing an iPad app. I allow both landscape and portrait mode. My UI is fine in portrait mode but when I change it to landscape mode, my UI gets messed up. I saw some SO posts related to this and I added following code in initWith... in my UIView.
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(abc)
name:UIDeviceOrientationDidChangeNotification
object:nil];
My UI is working fine in portrait mode after doing this. When I change it to landscape mode, my UI is fine. But after I change it back into portrait mode, my app crashes. I read some posts on SO related to app crashing an got to know about instruments. I enabled zombies and found that a message is being sent to already released object and this message is coming from NSNotificationCenter.
Is there something else that I need to handle apart from registering my device ? Also, is there any way where in I can change the implementation from UIView to UIViewController and implement the methods that UIViewController has regarding device orientation ? Please let me know the steps I need to follow in order to get this done. Thanks!
Where are you registering for the notifications? You need to remove the observer when you are about to change orientations (either in prepForSegue or willAnimateRotationToInterfaceOrientation depending on however you've got your setup) in order prevent messaging a no longer valid object. You also don't want to pile up several notifications if your registering in viewDidAppear/viewWillAppear.
Remove the observer using:
[[NSNotificationCenter defaultCenter] removeObserver:self];//removes all notifications for that object (the way I've used it before)
or if you want to be specific, do something like:
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceOrientationDidChangeNotification object:[UIDevice currentDevice];//remove just that notification
The UIViewController class has several methods that deal with changes in orientation. See the docs for a discussion of those methods.
One method you should look into is viewWillLayoutSubviews. This is a common place to perform manual view layout. This is called anytime the view controller's orientation changes.
Using these methods is much more common than registering for device orientation change notifications. Based on your statements about the crash, a possible issue is that you never remove the observer that you add. For every call to addObserver there must be a corresponding call to removeObserver. Otherwise the observer is called even if it has long gone away. And this results in the crash you describe.
Is there a notification or other mechanism of being informed that the user is taking a screenshot with the home/power buttons?
I've seen threads about wanting to disable the taking of screenshots, but that's not what I'm looking to do.
I have a photographer client who's concerned that his works will be copied by means of users taking screenshots and I thought that if there was an opportunity to put a watermark across the image before the screenshot was taken, that would allay his fears.
The PictureWasTakenNotification Darwin notification will be sent when the user takes a screenshot. However, this is sent after the screenshot is taken.
(No notifications will be sent before the screenshot was taken.)
Here's a way which might work, although it will totally go against user interface guidelines I'm sure. If you force the user to have their finger on the screen for the image to show then I don't think they can create screenshots. Because as soon as you press the home+lock keys to actually take the screenshot, the screen seems to behave as if there are no fingers touching it. Try taking a screenshot while moving between home screens to see what I mean.
Not a perfect solution by any means but you may be able to work it into your app design if you're really clever without it detracting too much from the user experience (a tough challenge though!). Nevertheless, I believe this may allow you to display artwork/photos without allowing users to take screenshots.
Since iOS 7 the UIApplicationUserDidTakeScreenshotNotification exists. So doing something like this should detect the screenshots:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(userDidTakeScreenshot) name:UIApplicationUserDidTakeScreenshotNotification object:nil];
}
- (void)userDidTakeScreenshot {
// Screenshot taken, act accordingly.
}
Finally, don't forget to remove the observer:
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationUserDidTakeScreenshotNotification object:nil];
}
What's really needed is a notification that is sent before the actual screen capture happens. A delegate method or some other means of giving the app a screenshotting-in-flight opportunity to redraw your content before the grab happens.
And there isn't one.