I have a project and I want to provide a feature to the user that allows them to change the background settings. I would like that change to carry through on all UI screens. What is the most efficient way of accomplishing this?
Right now I am able to keep the back ground detail in NSUserDefault. When loading the view I check getBG() and apply that background in viewDidLoad(). However, I don't think this is the most efficient way.
Make a class YourView in which you implement this behavior in the way that you like. It should inherit from UIView.
Then, change all your other classes from inheriting from UIView to inheriting from YourView instead.
(At least, I believe that you should be able to do what you want that way. If not, I just don't understand you correctly...)
You can use NSNotification.
When user changes the background image to one of his choice, then
post a notification
& add observer, to change the background, where u have set the background image.
Related
What should be the best way to create a effect like this and the handling of navigation controllers and view controllers ... what to do if I don't want to re-size each subsequent view in viewcontorller and things appear as if it is a tabBar
I would recommend using an UIImageView for the blue background, then 5 UIButtons of custom type with PNG images for the actual buttons.
Subclass UIView and put all the code to set up the background and buttons in the init function. That way you can easily place your custom TabBar wherever you like.
The individual buttons also allow you to easily animate them for transitions if you want.
Update to reflect updated question:
If you want the actual UITabBar functionality, things become much more complex.
You have three basic options:
a) Implement the functionality you need from scratch in your new class
b) Subclass UITabBar and try to override the drawing code with the code above
c) Take a look at already existing alternative implementations of UITabBar and base your new class on one of them. This will probably be the easiest solution.
I want to make a small area to present some information in the middle of a UIToolbar and was wondering what the best way to do this is.
I need to show some text and a graphic, both of which need to be updated (around every 3 seconds) as new information arrives. The graphic is similar to the iPhone signal strength indicator, so it can be either custom drawn or selected from one of 3 graphics (low, medium, high strength).
I'll probably use initWithCustomView: to create a UIBarButtonItem, although I would like the view to be clickable (to allow the user to change the information shown).
What's the best way to make that view? Can I use a NIB, or do I need to do custom drawing in the view? What's the best way to update the buttons? I'm assuming that I'll have to remake the toolbarItems array each time and set it when the information changes. Is there a cleaner way to do this? Thanks.
Using initWithCustomView: sounds like a good way to go. You can create your custom view any way you want: with a NIB, by drawing it, even using images. It can also have its own subviews. It can be any object that inherits from UIView. (So, if you wanted, you could even make it actionable by using a UIButton, a custom UIControl, or a custom UIView with a gesture recognizer attached.)
You shouldn't have to remake toolbarItems (or, for that matter, do anything with it after you've added all your button items) if you just keep a pointer to your custom view UIBarButtonItem. It could be an instance variable. Then, to update the custom view, you could access it as you would any other view. I've never actually tried this, but I can't see any problem with doing it.
You sound like you had it mostly figured out. Hope this is helpful.
I needed the same solution and was hoping for some code examples from you. So I ended up doing it all in IB and the steps are here as follows:
Create UItoolbar in IB with no Items. (A Bar Button Item will be added again once you add the UIView)
Add UIView as subview of UIToolbar
Add UILabels to subview of UIView that is already a subview of the UIToolbar.
Create IBOutlets from UIToolbar, UIView and each UILabel and then you can reference the labels in your app.
I did set the backgrounds to clearColor so the text appears on top of UIToolbar without any box or borders.
And the text updates dynamically which was the desired outcome.
Hope this helps someone as this has been eluding me for a while.
I have an app with an image view. When the user clicks on this view I want to run some code which will change the colour of a label and then hide this view
I have everything setup in the interface, i.e. Outlets etc, but I dont see any events available to associate
Can anyone help or point me in the direction of a good tutorial asap please?
Cheers
Paul
You shouldn't use an image view for this, you should use a UIButton. ImageViews are designed primarily to display, not allow for interaction (which is why their userInteractionEnabled flag is OFF by default.)
Take a look at the documentation for UIResponder - all UIViews, including UIImageView, inherit from it. In turn, UIResponder defines a set of methods you can override to handle the kind of event you're looking at. Start by subclassing UIImageView (call it MyImageView), then override the touchesEnded:withEvent: method.
As Ben Gottlieb said, however, this may be kind of an abuse of the UIKit framework - just make sure the user interaction you're creating makes sense and conforms to good UI practices.
The last time I needed to do this I just used a button also. You can always set up the highlighted state so that it doesn't highlight when someone taps on it if that's what you're trying to avoid.
Note that the higher level UI "actions" are implemented in UIControl, so if all you need to do is track actions like "Touch Up Inside" then it's possible to avoid the event layer, create a UIView in Interface Builder, then change the class to UIControl. You should then be able to use the connections inspector and connect any of those control actions to whatever.
If you place views inside the UIControl and the subviews have "User Interaction Enabled" unchecked (that is, user interaction is disabled) then taps and such inside the UIControl just ignore those and fall through to the UIControl. So another way to do this if you needed to for some reason would be to create a UIView, change the class to UIControl, then place one or more UIImageViews, UILabels, or whatever you want in your generic UIControl view. You can then get actions from the generic UIControl as if all that stuff wasn't inside it.
Is it possible?
I have a UINavigationBar that I'd like to have an 'edit' button next to the 'back' button. From what I've read you can only have one or the other, which makes no sense as they are separate properties of the navigationItem object(backBarButtonItem and leftBarButtonItem).
I'm assuming you have to somehow insert a custom UIView into the UINavigationBar. I'm looking into this option and if no better solution is given then I'll outline this method.
The short answer is:
Yes, you have to add your own UIButton views (or other UIControl subclasses) to the navigation controller, yourself. So, ignore the custom *ButtonItem properties and roll it yourself.
A little more involved answer is:
Apple makes it very easy to follow their HIG guidelines, but you're on your own if you want to break them or customize. In this case, only one button is allowed, because the actual hit region is bigger than the size of the displayed button--much easier to hit from a usability standpoint.
Extraneous:
btw, there is a subtle distinction between left/rightBarButtonItem and backBarButtonItem. left/right is specified on the current UIViewController. However back is specified by the previous UIViewController.
Using a custom view is indeed your only option here. The UINavigationBar is not terribly flexible. What you will need to do is create a UIView that contains UIButtons. Be sure you realize that if you use a custom view, you gain none of the automatic behaviors of the backBarButtonItem; you have to create your own IBActions, and the graphics for the buttons as well.
On a related note, I'm not sure this is the best idea. It's usually wise to stick to Apple's UI guidelines; is there no where else you can put the edit button? The right side of the bar, for example?
While #Kelvin's answer works for pre iOS 5, if you're using iOS 5+ there is now a leftBarButtonItems array property. Note that you also must set leftItemsSupplementBackButton to true.
I'm trying to design how to implement a relatively simple application.
I want to create a grid of 'squares' that cover an entire screen. Each square should have the ability to respond to touch events, and then have an on/off state. For example, if I touch an 'off' square, and then drag my finger across 10 other squares, I want them all to turn on. And vice versa.
I'm not sure of the memory overhead of just creating a grid of 150 buttons. Also buttons don't have a settable state, from what I can see. I was also thinking of subclassing UIView and implementing UIResponder methods. It feels like I should be creating an array of array of buttons (or subclass of UIViews), but I'm not sure if that's possible.
I'm assuming that I can tell what square I'm on by getting the location of the touchevent from the UIResponder methods. Do I need to create my own version of a myButton by subclassing UIView, and have a on/off state property, along with UIResponder methods, and then create an array of myButtons?
UISwitch is the only thing that does this at the moment, though some have had good experiences using the UISegmentedControl for this as well.
Beyond that, you'll have to change the style/color of a regular button or image in code, which is what a lot of application developers do so it looks and reacts exactly the way they want it to.
Unless you need more of UIView's event handling stuff, you'll get the best performance if you use a single view and give it a -touchesBegan:withEvent, -touchesMoved, and -touchesEnded methods. Then use a custom drawRect method to draw your individual squares in either on or off states. You could also use layers, but trying to lay out 150 views is asking for trouble.