I've recently started developing an iOS app, which I've never done before, so it's been going a bit slow, but I'm learning, so that's understandable.
I want to make a custom interface, so I've been making subclasses of the default view classes (like UIButton) so that I can define custom drawing. I've been told this is the best way to define custom interface elements that can be reusable. It definitely seems to be working that way. However, I haven't been able to make elements completely reusable by just using a subclass.
For example, in order to prevent a button's text from changing color when it is clicked, I have to manually go into the interface builder and set the button type to "Custom." After that, code that I enter into the subclass's constructor to change attributes seems to work. But I have to do this for every button I add, and in code the "buttonType" attribute is read only. Is there a way for me to define (just once) certain attributes for every instance of my button subclass that I add to the interface?
My goal is to be able to have a button subclass or template that defines all attribute values that I want my buttons to have, and every instance that I add automatically reflects those properties without me having to change anything. More so, I want to be able to modify that subclass/template and have those changes reflected in every existing instance. I have to imagine that this is possible in iOS. There is simply no way to build sophisticated interfaces without this capability.
Define a custom Button class (inherited from UIButton) in your project and in the init set the properties which you wanted to be set across.
In the interface builder go to the the class inspector and enter the button to be of the previously declared button.
buttonType needs to be set for all the button as this is defined at initialization time and exposed as read only property. If you want absolute reusability for your case, create a view, with an embedded button in code. when you create a button, create using the static method buttonWithType.
Wherever you need, drag and drop a UIView and set the view type to be the custom view.
Related
I have a bunch of static objects (UILabel, buttons, views) in multiple Scenes. They are not connected to any IBOutlet. But I'd like to access them at appdelegate (or first VC), and change their properties before it is loaded.
Anyway to do this?
EDIT: Adding my intention:
I actually wanted to make a custom "multi-language" app. I want to be able to change language from within the app. I can get a list of all the objects by applying built in localization of storyboard (Main.strings is autogenerated). Then I disable localization again. Then from this autogenerated file, I want to be able to connect it to a json data based on language that I select.
Of course you can. For example, you can use tags of UIView. Just set tags in Storyboard. It's easy but not so good. Another way to do this is using Accessibilities. Enable and set for it in Storyboard.
And then you can access it by accessibilityIdentifier property.
I will post my choice of "solution". So what I did was make use of accessibilityIdentifier to set the "key" for the multilanguage phrase translation purpose.
And I make use of the UIView+Recursion class (you can find this simple class somewhere in SO), and basically iterate all the objects in a particular Scene and if the text matches, set the key in accessibilityIdentifier property (either in viewDidload or viewWillAppear or viewDidlayoutSubviews).
This way you can have language changes "on-the-fly" within the app, without restarting.
I would like to be able to interact with the UIControl I have made, and therefore want it in my ViewController.
What I tried
I subclassed UIControl (1).
Then I added a UIView to my View Controller and assigned it the new class (2).
But in Interface Builder I am not able to set my outlets to the buttons contained in the new class (1)?!
1:
2:
UIControl's documentation confirms that it is a subclass of UIView, and I should therefore be able to connect the outlets, right?
What am I missing here? :/
Off-course you can't add IBOutlet because buttons what you added to WeekdayControl are in UIViewController, you can't add Outlet to WeekdayControl, buttons only subviews of WeekdayControl, UIViewController is boss here, and you can add outlet only to UIViewController. (Sorry for my English)
Better create you buttons programatically in WeekdayControl.
Must read first:-
You cannot use the UIControl class directly to instantiate controls.
It instead defines the common interface and behavioral structure for
all its subclasses.
The main role of UIControl is to define an interface and base
implementation for preparing action messages and initially dispatching
them to their targets when certain events occur
So, you are doing wrong, if you really need to make a custom view or custom control then you can directly do it by creating a custom UIView and connecting the outlets directly with the view.
I think you missing the objective of subclassing a UIControl, it doesn't give rights to create outlets as it's a subclass of UIView,just read this lines what it is stated in the docs:-
Subclassing Notes
You may want to extend a UIControl subclass for either of two reasons:
To observe or modify the dispatch of action messages to targets for
particular events
To do this, override sendAction:to:forEvent:, evaluate the passed-in
selector, target object, or UIControlEvents bit mask, and proceed as
required.
To provide custom tracking behavior (for example, to change the
highlight appearance)
To do this, override one or all of the following methods:
beginTrackingWithTouch:withEvent:,
continueTrackingWithTouch:withEvent:, endTrackingWithTouch:withEvent:.
I have a custom singleton MyColors class to easily change colors of some buttons easily in many UIViewControllers at the same time.
I put #import "MyColors.h" in every class I need to get color of a button.
Everything works perfectly and setting a the color value in MyColors, that color is applied correctly to where I want.
Now, I want to change colors alive. So I send a NSNotification with name "COLORS_CHANGED".
So every class will observe that and apply colors immediately.
What I want to do is:
Force XCode to remind me that the .mfile that includes MyColors.h must also include colorsChanged method for observing. So, this will prevent me forgetting to add observer
OR:
Add something like a Category or something like that into MyColors.h to do this kind of thing...
What I don't want to do:
I don't want to create a protocol and add it as delegate to header files of every .mfile that includes MyColors.h. Because I can forget that too.. If not, this would be the way ofcourse...
So, I am trying to find an Objective-C way to do this, or a compiler way that works with XCode to do this.
Thank you for sharing your ideas.
Update: I use color values for anything that needs colors not just buttons.
implement this functionality in a base class and make all your UIViewController-s inherit it. i.e - in the base class register for this notification and change the common objects' colors and also call there a virtual method for the inheritors to change their extra objects' colors.
Good luck,
A quick question from a wanna-be iOS developer. I want to create a UI for an iPhone app without Interface Builder, only programmatically. However, I want to stick to MVC recommendations and separate V and C and have a clean readable code, therefore:
I create UIView class files (e.x. SplashView.h and SplashView.m)
I create UIViewController class files (SplashViewController.h and SplashViewController.m)
I define my UI elements (view, subviews, buttons and text fields) in the UIView class files
I load the main view in view controller's loadView method, and then do other things in view controller's viewDidLoad method
Is this a correct approach to begin with?
Second part of the question, independent of Y/N answer to the first. Where do I define these custom UI elements?
- Inside the view's initWithFrame: method?
- In separate (property getter? property setter?) methods? I.e. do I have to declare each UI element as a property first in the .h file?
If these questions sound a bit ignorant, it must be because they are :) I found lots of sample code on StackOverflow, but little to indicate where you actually put it. I would be really grateful for any help, especially if you could paste/reference some relevant code.
Your list is correct. This is how I do all of my apps. No Interface Builder, just code.
Each custom view typically creates its own subviews in an appropriate initXXX method. This could be initWithFrame: but you could define others as needed. Subview layout can be done through constraints, autoresizing masks, or by implementing layoutSubview.
Each view controller would instantiate its needed views in the viewDidLoad. View layout can be done with constraints, autoresizing masks, or by implementing viewWillLayoutSubviews.
The use of properties is completely optional. Create public properties for anything to be set/get from an outside class. Optionally create private properties for values internal to the implementation.
Go to the Apple website for Sample Code; download everything that you can for applications that are similar to your goal.
I have an iOS app with multiple ViewControllers. Each view has numerous IB generated UIButtons, each set to custom. I need to change the color of the background in normal and highlighted states. Further, I need to vary the colors to an RGB value based on user interaction. Thus, I can't use image files.
I found an example of a custom class derived from UIButton that implements the color change and click methods to change the colors as I desired. I created a test button and changed its IB custom class to my new class.
I have an outlet property for my IB created button.
The problem I am having is in the viewcontroller.m file when I attempt to access the custom method in my class, xcode can't see the methods.
Use IBAction as a return type for that method
Declare that particular method in .h file