I need to download and show an image on the Splash of my application. But I don't know if this is possible or a good practice on the splash, even I wanna know if there's a workaround to make this.
Thanks.
LaunchScreen.storyboard (or Xib) is tremendously limited in functionality compared to a regular storyboard. You won't be able to do much on it.
The only possible way is to have a SplashViewController or the name you prefer as first Window's rootViewController. (can be defined in AppDelegate's application(_, didFinishLaunchingWithOptions) or Main interface in General tab of the Application target.
The initial layout of that first SplashViewController should be exactly as your LaunchScreen, trying to avoid a visual jump between them. After that you're free to show whatever you want.
Obviously, if you are going to do network load or any other type of task that delays the launch, it is convenient to show the user something that indicates this work. As far as possible cache so that in future launch the start is as fast and smooth as possible.
I'm an Android developer, I started learning iOS development lately and I've been wondering about how to manage the UIViewControllers.
In Android, when you don't need an activity anymore, it is better to remove it from the application stack, for example a login screen is only needed when the user logs in, after that there is no need for that screen so it is better to destroy it and remove it from the stack, but what about iOS? Do you have to manage view controllers the same way as activities? or does the system automatically handle the views in the background?
It would be great if you can link some reference to read more about the way View-controllers are handled in the background, I'm trying to learn the best practices
Short answer: No, let ARC handle it
ARC handles the release from memory automatically when you pop a view from a navigation stack, so if you go "back" (pop) you normally don't need to worry about it.
But, sometimes you have a big navigation stacks with many different views with a lot of data/images/etc that will eat memory. In those cases you could separate your app into different flows and instead replace the root view controller of the main window with the new flow every time you want to change. The old flow should be released from memory automatically, unless its connected to another object (like a singleton).
When I click new file and go to user interface tab, I don't see the application or window options. The application file description should say "An Interface Builder document suitable for creating an iOS application, including an application delegate and window." I tried searching in the search bar in Xcode but application did not show up for iOS.
Please see screen shots and difference for clarity.
app delegate screenshot 2
my screen
Apple introduced storyboards back in 2011. Before that, developers used a .xib file to specify their user interfaces, and the "main" .xib file, i.e. the first one that the app loaded, included a proxy for the app delegate so that it was easy to connect objects to outlets in the app delegate. As matt has indicated, though, things haven't really worked that way for a while. As he says, it sounds like you're working from an old book or online tutorial, and as a result your expectations don't match the reality of modern iOS development.
These days, apps generally use a storyboard to specify all or part of the user interface. A big problem with .xib files was that you had to load an entire file at once; if you instantiated a view controller with -initWithNibName:bundle:, the entire file was loaded. That meant that you could only specify a single view controller in a given .xib file, and managing the relationships between view controllers was harder than it should be. Storyboards address this problem -- a single storyboard typically contains several view controllers.
I agree with matt that you really shouldn't work from material so old that it expects you to use .xib files to build your application. That story again:
STOP USING THAT INFORMATION
There are plenty of great resources (notably matt's own iOS 9 Programming Fundamentals with Swift) that will teach you how to write modern iOS code. Apple's own documentation is a great place to start.
Our company is developing a quite large app for the iPad. Eventually we want to be able to customize the UI per customer (tenant) and maybe even per user (of that customer). We started off in HTML5 but are moving to native.
I've done some reading on downloading XML from the server (or even generated XIB/NIB files) and dynamically adding those to your app.
Now with iOS 5 (and even further in 6) storyboarding is playing a big role.
My questions:
- Would it be better to use (multiple?) storyboards or XIBs?
- What are my options for both if I want to deliver a dynamic user interface?
I'm not looking for a magic pill, nor a discussion on HTML5 vs native, just some information on how I could deliver a dynamic interface and what techniques could help in doing so.
my response to your two questions is:
storyboard is great for scene management; it creates a visual connection between
your various scenes/views. i prefer to use storyboard for as much of my UI as possible.
however, there are elements that i have in some apps that pick up existing or reusable
or otherwise dynamic XIBs. i simply tie these together with my storyboards by loading
the XIBs in code at the location at which i want them. so, my ultimate answer for your
first question is "both", where storyboards are used where possible, and XIBs used for
dynamic scenes/views.
your options for dynamic user interface include at least the following two options (of which, as stated above, i prefer the second):
create all code using XIB files, and perform all UI transitions without storyboards
in code
create as much UI as you know will remain relatively static in terms of relationships
between viewControllers with storyboard, and then load the dynamic parts of the UI
using initWithNibName:bundle:
finally, you can use multiple storyboards if the situation warrants, and this could even apply to dynamic UI, whether it comes from re-usable components created elsewhere in storyboard and maintained separately, or storyboard XML (if you look at storyboard source, it is just XML under the hood) whether acquired from something that generated or wherever. you can even decide to manage your UI with multiple storyboards at the design phase if your app will have several complicated interconnected view-controller scenes (e.g. each tab in a UITabBarController may have its own storyboard, where each storyboard's scene rootController is connected/loaded when a tab is chosen).
StoryBoard all the way! I use to absolutely dislike storyboards, but then i got use to them and now i love them. Storyboards are the way to go.
Layout seems a really powerful framework for developing dynamic GUIs on iOS.
DISCLAIMER: I'm not the author of that framework; the author is Nick Lockwood, who seems to have an account here on SO. I found both this question and Nick Lockwood's Layout framework by googling "ios dynamic gui".
I haven't tried it yet, but it looks really promising.
The project is even hosted at GitHub here, and it has a MIT license.
Are there any guidelines on when to use storyboards in an iOS project and when to use XIBs? what are the pros and cons of each and what situations do they each suit?
Near as I can tell it's not that clean to use storyboard segues when you have view controllers being pushed by dynamic UI elements (Like map pins).
Update 1/12/2016: It's 2016 and I still prefer laying out my UIs in code and not in Storyboards. That being said, Storyboards have come a long way. I have removed all the points from this post that simply do not apply anymore in 2016.
Update 4/24/2015: Interestingly Apple doesn't even use Storyboards in their recently open-sourced ResearchKit as Peter Steinberger has noticed (under the subheading "Interface Builder").
Update 6/10/2014: As expected, Apple keeps improving Storyboards and Xcode. Some of the points that applied to iOS 7 and below don't apply to iOS 8 anymore (and are now marked as such). So while Storyboards inherently still have flaws, I revise my advice from don't use to selectively use where it makes sense.
Even now that iOS 9 is out, I would advise against to use caution when deciding whether to use Storyboards. Here are my reasons:
Storyboards fail at runtime, not at compile time: You have a typo in a segue name or connected it wrong in your storyboard? It will blow up at runtime. You use a custom UIViewController subclass that doesn't exist anymore in your storyboard? It will blow up at runtime. If you do such things in code, you will catch them early on, during compile time. Update: My new tool StoryboardLint mostly solves this problem.
Storyboards get confusing fast: As your project grows, your storyboard gets increasingly more difficult to navigate. Also, if multiple view controllers have multiple segues to multiple other view controllers, your storyboard quickly starts to look like a bowl of spaghetti and you'll find yourself zooming in and out and scrolling all over the place to find the view controller you are looking for and to find out what segue points where. Update: This problem can mostly be solved by splitting your Storyboard up into multiple Storyboards, as described in this article by Pilky and this article by Robert Brown.
Storyboards make working in a team harder: Because you usually only have one huge storyboard file for your project, having multiple developers regularly making changes to that one file can be a headache: Changes need to be merged and conflicts resolved. When a conflict occurs, it is hard to tell how to resolve it: Xcode generates the storyboard XML file and it was not really designed with the goal in mind that a human would have to read, let alone edit it.
Storyboards make code reviews hard or nearly impossible: Peer code reviews are a great thing to do on your team. However, when you make changes to a storyboard, it is almost impossible to review these changes with a different developer. All you can pull up is a diff of a huge XML file. Deciphering what really changed and if those changes are correct or if they broke something is really hard.
Storyboards hinder code reuse: In my iOS projects, I usually create a class that contains all the colors and fonts and margins and insets that I use throughout the app to give it a consistent look and feel: It's a one line change if I have to adjust any of those values for the whole app. If you set such values in the storyboard, you duplicate them and will need to find every single occurrence when you want to change them. Chances are high that you miss one, because there's no search and replace in storyboards.
Storyboards require constant context switches: I find myself working and navigating much faster in code than in storyboards. When your app uses storyboards, you constantly switch your context: "Oh, I want a tap on this table view cell to load a different view controller. I now have to open up the storyboard, find the right view controller, create a new segue to the other view controller (that I also have to find), give the segue a name, remember that name (I can't use constants or variables in storyboards), switch back to code and hope I don't mistype the name of that segue for my prepareForSegue method. How I wish I could just type those 3 lines of code right here where I am!" No, it's not fun. Switching between code and storyboard (and between keyboard and mouse) gets old fast and slows you down.
Storyboards are hard to refactor: When you refactor your code, you have to make sure it still matches what your storyboard expects. When you move things around in your storyboard, you will only find out at runtime if it still works with your code. It feels to me as if I have to keep two worlds in sync. It feels brittle and discourages change in my humble opinion.
Storyboards are less flexible: In code, you can basically do anything you want! With storyboards you are limited to a subset of what you can do in code. Especially when you want to do some advanced things with animations and transitions you will find yourself "fighting the storyboard" to get it to work.
Storyboards don't let you change the type of special view controllers: You want to change a UITableViewController into a UICollectionViewController? Or into a plain UIViewController? Not possible in a Storyboard. You have to delete the old view controller and create a new one and re-connect all the segues. It's much easier to do such a change in code.
Storyboards add two extra liabilities to your project: (1) The Storyboard Editor tool that generates the storyboard XML and (2) the runtime component that parses the XML and creates UI and controller objects from it. Both parts can have bugs that you can't fix.
Storyboards don't allow you to add a subview to a UIImageView: Who knows why.
Storyboards don't allow you to enable Auto Layout for individual View(-Controller)s: By checking/unchecking the Auto Layout option in a Storyboard, the change is applied to ALL controllers in the Storyboard. (Thanks to Sava Mazăre for this point!)
Storyboards have a higher risk of breaking backwards compatibility: Xcode sometimes changes the Storyboard file format and doesn't guarantee in any way that you will be able to open Storyboard files that you create today a few years or even months from now. (Thanks to thoughtadvances for this point. See the original comment)
Storyboards can make your code more complex: When you create your view controllers in code, you can create custom init methods, for example initWithCustomer:. That way, you can make the customer inside of your view controller immutable and make sure that this view controller cannot be created without a customer object. This is not possible when using Storyboards. You will have to wait for the prepareForSegue:sender: method to be called and then you will have to set the customer property on your view controller, which means you have to make this property mutable and you will have to allow for the view controller to be created without a customer object. In my experience this can greatly complicate your code and makes it harder to reason about the flow of your app. Update 9/9/16: Chris Dzombak wrote a great article about this problem.
It's McDonald's: To say it in Steve Jobs' words about Microsoft: It's McDonald's (video)!
These are my reasons for why I really don't like working with storyboards. Some of these reasons also apply to XIBs. On the storyboard-based projects that I've worked on, they have cost me much more time than they have saved and they made things more complicated instead of easier.
When I create my UI and application flow in code, I am much more in control of what is going on, it is easier to debug, it is easier to spot mistakes early on, it is easier to explain my changes to other developers and it is easier to support iPhone and iPad.
However, I do agree that laying out all of your UI in code might not be a one-size-fits-all solution for every project. If your iPad UI differs greatly from your iPhone UI in certain places, it might make sense to create a XIB for just those areas.
A lot of the problems outlined above could be fixed by Apple and I hope that that's what they will do.
Just my two cents.
Update: In Xcode 5, Apple took away the option to create a project without a Storyboard. I've written a small script that ports Xcode 4's templates (with Storyboard-opt-out option) to Xcode 5: https://github.com/jfahrenkrug/Xcode4templates
I have used XIBs extensively and completed two projects using Storyboards. My learnings are:
Storyboards are nice for apps with a small to medium number of screens and relatively straightforward navigation between views.
If you have lots of views and lots of cross-navigation between them the Storyboard view gets confusing and too much work to keep clean.
For a large project with multiple developers I would not use Storyboards because you have a single file for your UI and cannot easily work in parallel.
It might be worth for large apps to split up into multiple storyboard files but I have not tried that. This answer shows how to do segues between storyboards.
You still need XIBs: In both of my Storyboard projects I had to use XIBs for custom table cells.
I think Storyboards are a step in the right direction for UI implementation and hope Apple will extend them in future iOS versions. They need to resolve the "single file" issue though, otherwise they won't be attractive for larger projects.
If I start a small size app and can afford iOS5 only compatibility, I would use Storyboards. For all other cases I stick to XIBs.
Storyboards were created to help developers visualize their application and the flow of the application. It is alot like having a bunch of xib but in a single file.
There is a question similar to this located What is the difference between a .xib file and a .storyboard?.
You can also create custom transitions via code that will change dynamically if needed, much like you can with .xibs.
PROS:
You can mock up flow of an application without writing much, if any code.
Much easier to see your transitions between screens and your application flow.
Can also use .xibs if needed with storyboards.
CONS:
Only works with iOS 5+. Does not work with iOS4.
Can get cluttered easily if you have a very view intensive application.
There really isn't a right / wrong when to use one or the other, it is just a matter of preference and what iOS versions you are wanting to use.
I will just state 4 simple reasons why you should use storyboards, especially in a productive environment where you have to work in a team of product owners, product managers, UX designers, etc.
Apple has GREATLY improved working with Storyboards. And they encourage you to work with them. Which means they will not break your existing projects with updates, they will ensure that storyboards are future proof for newer XCode/iOS versions.
More visible results in less time for the product owners and managers, even during the creation phase. You can even use the storyboard itself as a screenflow diagram and discuss it in meetings.
Even after an app is done (and that's generally where its life-cycle begins) – in the future it will be faster and easier to apply small adjustments. And these could very well change multiple aspects of your layout at the same time, which you probably want to see in a WYSIWYG manner. The alternative would be hand-writing UI changes in code and switching back and forth between the IDE and the simulator to test it out, each time waiting for compile & build.
Non-developers can be taught to set up layouts in storyboards and create the necessary hooks for the developers (IBOutlets and IBActions). That's a very big plus because it lets the devs focus on the logic and the UX designers apply their changes in a visual manner, without having to write any code at all.
I won't write up any CONS, since Johannes has already listed probably all the viable ones in his answer. And most of them are definitely not viable, especially not with XCode6's major improvements.
I don't think there is a right answer for your question, it's just a matter of personal experience and what you feel more confortable with.
In my opinion, Storyboards are a great thing. It's true, it's really hard to find out why your app is misteriously crashing at runtime, but after some time and experience you'll realize it's always related to some IBOutlet missing somewhere and you'll be easily able to fix it.
The only real issue is working in team under version control with storyboards, in the early stages of development it could be a real mess. But after that first stage, UI updates that completely changes the storyboard are very rare, and in most cases you end up with conflicts in the very last parts of the xml, which are segue references that usually autofix themselves when you re-open the storyboard. In our team work we prefered to deal with this instead of heavy view-controllers with tons of view code.
I've read many comments againts auto-layout. With XCode5 it got really improved, It's really good even for autorotating layouts. In some case you'll have to do something in code, but you can simply outlet the constraint you need to edit and, at that point, do what you need in your code. Even animate them.
I also think that most of the people who dislike storyboards didn't fully try to understand the power of a custom manual segue, where you can totally customize (in a single file) the way you transition from a way to another and also (with some tricks) even reuse a previously loaded view controller by just updating it's view contents instead of fully reload the whole thing.
At the end you can really do the same things as in code, but I think you have a better separation of concerns with storyboards, but I agree that in many things they lack of features (fonts, image as color background, ecc...).
I am not using StoryBoard or XIBs in my any of the app.. but creating everything programmatically.
∆ Benefits :
√ You can create any complex kind of UI or transition animations for UIView's.
√ Support all iOS versions. No need to worry about < iOS 5.
√ *Your app would support all iPhone/iPod/iPad devices within your code.
√ You're always updated as you know the code that'll always work.
√ *Will work on any (new) device launched – No need to change in code.
√ Everything is upto you. At certain place you want to change something – No need to look into storyboard or xib. Just search for it in particular class.
√ Last but not the list – You'll never forget that, how to manage everything programmatically. This is the best thing as you know a control very deep then anyone.
I've never find a problem by not using SB or XIBs as I'm good with this.
* if you've set UIKit's object frames according to screen size.
P.S. If you've still not done this thing – you may faced difficulty (or may feel boring) but once you get familiar with this – its really a Candy for you.
If you are about to care about Storyboard performance, watch WWDC 2015 Session 407
Build Time
When interface builder is compiling a storyboard it's doing two things
first, it's trying to maximize the performance of your application and
secondly it's also minimizing the number of nib files created.
If I have a view controller with a view and a bunch of sub views,
interface builder, the build time is going to create a nib file for
the view controller and create a nib file for the view.
By having separate nib files for both the view controller and the
view, this means the view hierarchy can be loaded on demand.
Run Time
When you allocate a storyboard instance using UI storyboard, API,
initially all you are allocating memory for is the UI storyboard
instance itself.
No view controllers no views yet.
When you instantiate your initial view controller it will load the nib
for that initial view controller but, again, no view hierarchy has
been loaded yet until someone actually asks for it.
I have been working on a reasonably sized project (>20 scenes in storyboard parlance), and have come across many limitations and have to repeatedly go to documentation and google searches for doing things.
The UI is all in one file. Even if you create multiple storyboards, you still have many scenes/screens in each storyboard. This is a problem in medium-large teams.
Secondly, they do not play well with custom Container Controllers which embed other container controllers etc. We're using MFSlideMenu in a Tabbed application and the scene has a table. This is almost impossible to do with a storyboard. Having spent days, I've resorted to doing the XIB way where there is complete control.
The IDE does not allow to select controls in zoomed-out state. So, in a large project, the zoom-out is mostly to get a high level view and nothing more.
I would use storyboards for smaller applications with small team sizes and use XIB approach for medium-large teams/projects.
If you want to reuse some UI in multiple view controllers then you should use XIBs