I have a camera application that uses my custom overlay on the UIImagePickerController object.
I am calling the takePicture method to take a picture when the user presses a button on my overlay view. Something like:
[imagePicker takePicture];
[self showProcessingIndicator];
The processing indicator is the usual spinning wheel that shows that a picture is being taken. I notice that often the camera does not take a picture immediately after the takePicture method is called, and the processing indicator is showing.
It seems that the camera tries to adjust its focus (if it is out of focus) and then takes a picture. This is probably the right thing to do. However, I have also noticed delay in taking a picture even when the camera is focused correctly and does not change its focus. This does not happen every time, and its hard to say when exactly it happens.
My question is: is there a way to force the camera to take a picture instantly, ignoring everything else? Also, is it possible that subsequent processing (showing the indicator view, for example) is causing the camera to respond slower on occasion?
Thanks!
I have also seen this and came to the conclusion that taking a picture is a reasonably resource-hungry operation in terms of talking to the camera device, allocating/moving memory, etc. While you can tune your application to not soak up any resources while this piece is running, you can't tell MobileMail, MobileiTunes, etc, to not check for email, etc, at that precise moment.
Is there any particular iOS version or device that this happens on more than others? Taking a picture on my iPhone 3G with iOS 4.0.x took up to 30 seconds, but is much improved on iPhone 4.
The activity indicator will soak up some resources, so this may be a candidate for removal and maybe just use sound instead. Test to be sure.
Related
I have added a Default.png picture to my resource folder and the picture is now correctly displayed when the app is launched. But right now I have a problem that the time of the picture shown on screen is just too short and user just doesn't have enough time to take a look at the pic. And idea? Thanks
Make a viewController with an imageView containing the launch image. Then have that viewController load first, and set it to change after some fixed amount of time.
You could load the image onto the screen in the applicationDidFinishLaunching:withOptions method and then trigger a delay (using performSelector:afterDelay) to remove that image after a certain amount of time. That doesn't help you have a consistent load screen time, since the actual load time will vary per device, but it does let you pad the load time a bit.
I suppose if you want to get really fancy, you could pad the load time varying amounts depending on the device. Whatever you do I'd keep it to only an extra second or two.
Maybe you should take a look at Apples description, what the launch image is exactly for. I strongly recommend not to annoy the user with longer than needed "splash screens". Keep in mind, that there are people with devices, which don't support multi tasking. Using your app while getting text messages or other push notifications, switching to another app and back to yours is frustrating big time, if they have to wait until you think, they have payed enough attention to a (mostly) useless image.
Please, think about avoiding the use of nag screens. :)
I am writing an application for a 2g device and I am receiving memory errors. The errors are created by saving a large file to the device while searching sql libraries and displaying popups (picker view mostly).
I know this is a bit vague but I was wondering if there was a way to pause user interaction while letting the device complete processing it's data. I have tried using sleep(), and [NSThread sleepForTimeInterval: 0.5], but this all pauses the application also.
Preferably this would be called in didReceiveMemoryWarning to let the app catch up processing data while blocking user interaction.
Thanks
One option is to add an invisible (i.e. transparent) view on top of all the others. Ideally, you reduce its alpha value to make it sort of gray out the underlying user interface and display a spinner or something like that to indicate that the device is working.
I'm about to finish an app and now I wanted to add an animated splash screen with my company logo after the app finishes loading and launching. I can just use an animation with openGL for this, but I was wondering if it would be better to use a video..it's easier for me and the artist because he will only provide with an small video which i would reproduce after my app finish launching..less work.
I wonder if it's a good idea to do so...can I reproduce a small short video with the logo of my company or should i stick to making an animation ?
Also, reproducing video is memory intensive ?, because I'm loading some texture after my app finishes launching, and im wrried about that.
If i end up reproducing an small video, can i make it non interactive ? ( no pause, play stop, ect) so it looks like just as another animation to the eyes of the user ?
My other preocupation is quality...the quality of the video will look dramatically different to my animations in openGL ?
Thanks !
I can't tell you about the technical stuff, but what I can tell you is: don't use a splash screen. Directly from the Human Interface Guidelines:
Supply a launch image to improve user experience; avoid using it as an opportunity to provide:
• An “application entry experience,” such as a splash screen
...
Because users are likely to switch among applications frequently, you should make every effort to cut launch time to a minimum, and you should design a launch image that downplays the experience rather than drawing attention to it.
The HIG guidelines are intended (as far as I can tell) for Apps on the iPhone.
This is different from Games on the iPhone.
If your app provides some utility to the user, I agree completely with #Costique, #fabian789, and the HIG. The app should start instantly, with minimal loading and other distracting crap.
For a game, however, intros and the like are not only expected, but can also lead to a better user experience. My recommendation is to use a UIView Animation for only a small portion of the screen (the logo only). See Angry Birds as an example - their "animation" starts the same time the user's options do, so your animation (while quite pretty) doesn't block the user from using your app.
Disclaimer: the following is an entirely subjective humble user opinion. Please, don't take it to heart.
I hate video splash screens on my iPhone/iPad, however beautiful and stylish. What I like is apps which launch instantaneously. On iOS 4 chances are, I will see the startup animation once a month when the OS decides to terminate your app when the device is low on memory. So, now I tap the app icon and see the animation, now I tap it and don't (because it's already launched). It's inconsistent, out of your (and my) control, and ultimately makes little sense.
From both quality and aesthetics points of view, I think GL animation would better fit (hopefully) intense addictive action which follows. I'm not sure, however, that you will be able to load any resources in the background, while the animation plays, without making the animation stutter.
Hello I'm trying to get the multitasking work properly, but unfortunately I'm kinda lost. My problem is when I re-enter the game, it takes several seconds for the game to come back and show the pause screen. My question is; is there any way to put some sort of loading screen until the game comes back, so I can at least indicate that its not frozen? I've never used Xcode directly. I'm using Unity 3d to build my game. I made a little bit of research and if I'm not mistaken I'm supposed to use "applicationDidEnterBackground" app delegate method. My question is How can I put a custom loading screen using that method in Xcode?
Thanks
In -applicationDidEnterBackground:, you're given the opportunity to "clean up" the UI before the screenshot is taken. Apple says you should remove "sensitive data" (the screenshots might be persisted to "disk"?), but it also lets you do other things. In one app, we hide the label on a countdown timer so it doesn't appear to jump when you switch back to the app.
To change the "loading screen", simply display a full-screen view over the other views and remove it in -applicationWillEnterForeground:. Alternatively, pause the game in the first place!
(Really, you should be pausing the game in -applicationWillResignActive: which happens when the user double-taps home or the user receives a SMS/notification. I'm pretty sure it's called when the app is backgrounded, too.)
I have used to loading a default image in my appication. So i have set to,
Sleep(3); in my delegate.m class.
But sometimes it will take more than 6 to 7 minutes. So i want to display the image 3 seconds only and then it goes to my appilcation based on my requirements.
Which one is best way to do that?
Sleep(3) or [NSThread sleepForTimeInterval:3.0] or something else;
And i must display the image 3 seconds only. Please explain me.
(Note: And I declared setter and getter methods only in my deleagte class.)
Please explain me.
As Rob noted, Apple strongly recommends against a splash screen unless it hides some necessary behind the scenes process (like loading game graphics.) It is so strongly discouraged that some people have claimed that their apps have been rejected for using an unnecessary splash screen.
The default.png doesn't exist to create a splash screen. Instead it exist to allow you to create the illusion that your initial view loads faster than it does. You supposed to use it to provide an image of your initial view so that the enduser can begin to cognitively orient themselves to the interface. By the time they have oriented themselves to the interface and moved their finger to touch the interface, it is live.
Why? Because iPhone apps are supposed be quick in, quick out. People don't sit down to use them at a desk like a desktop. People use then on the go. Sometimes they use them in the middle of a conversation.
I tell my clients to test out the usability of their apps (except for games) while walking, riding an exercise bike etc as well as in the middle of a face-to-face and phone conversation. In those circumstances, a three second pause is a big deal and very noticeable especially if the app is a practical app. Imagine if every time you opened the Contact app you had to pause three seconds to see an Apple splash screen. You would get peeved in a hurry.
The key thing here is that an unnecessary splash screen doesn't add any value for the user. It is a selfish act on the part of the software publisher to eat the end users time so that the publisher can build brand recognition for the sole benefit of the publisher. Wasting three seconds of the users time every time they use the app adds up in a hurry. (In my experience, it also makes the user perceive that the overall app is slow and clunky.)
However, if you do want to shoot yourself in the foot or if you have a client hell bent on a splash screen, you do it like this:
The splash screen appears until the first view loads so you delay the loading of the first view. In the app delegates applicationDidFinishLaunching: method, remove all the code that loads the first view into the window. Replace it with a NSTimer. Put the code to load the first view in the timer's fire method.
With that setup the app will display the default.png as it launches, when it gets to applicationDidFinishLaunching:it will appear to pause from the end users perspective because no view will appear to replace the default.png.
You should note that the standard launch time for an app is 3-5 seconds. So you may not have to do anything to show the splash screen for 3 seconds. It might happen automatically.
Apple strictly recommends against this (using sleep in this way), especially in the scenario of showing a splash screen.
The best thing to do is create a view that looks like your Default.png file, then have that be the first NIB.. you could then set an NSTimer to transition (with animation if you want) to your main view/window/controller.