Currently, when selecting components or swiping the UIPickerView, the default is a lengthy animation time waiting for the selection, with a "gravity" effect near values. Is there a simple way to speed up this animation? I've looked at the delegate protocols as well as UIPickerView's methods and properties. Will I have to subclass and overload the animation method? Any help will be useful.
There is no way to do this. If you'd like for there to be a way to do this, please file a bug asking for it.
Also, relying on implementation details and a particular interval view hierarchy, as Fabian suggests, is a really excellent way to introduce a ton of fragility into your application and open the possibility of your app breaking in the future, should UIKit ever change anything.
I don't know of a way to achieve that using public API, but UIPickerView uses a UIPickerTableView as a subview somewhere in its view hierarchy. That is a subclass of UITableView which is a subclass of UIScrollView which has a decelerationRate property.
You shouldn't use private API, though. If you really need this and it's not for an App Store app this might be okay, but you should be careful and code defensively.
I don't have 50 rep, so can't comment on this (which is where this should really go). This question shouldn't have been downvoted since the question is legitimate. The valid answer is "no, you can't do that without private API hacks"), but the question is still valid.
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Want to create a loading view that matches the speed of the UIActivityIndicatorView depending on the network type.
Is it accessible via the SDK or at the very least disclosed?
How fast it spins? Short answer is no :(
Not with a simple property or something like that. You do have a few options though:
Create it yourself. The images are available when you use iOS Artwork Extractor, so you could give it the same look. Perhaps a little tedious. Maybe you could even subclass it.
Do some hackery with the current startAnimating and stopAnimating methods. Basically start and stop it for a period of time using a timer. This may not look great though as NSTimer doesn't always give you the precision you'd want in this case.
Since UIActivityIndicatorView inherits from UIView, you can access its layer property. This is a CALayer, which has instance methods like animationKeys and animationForKey. This is probably the best way to go about it, though it's not very future-proof since you're modifying the internals which can always change.
I'd like to know which is the best way to setup an NSView.
The only method suitable for this purpose, seems to be viewDidMoveToSuperview.
In this method I can add subviews and inviewWillMoveToSuperview I can do geometry operation on frame etc.
But these are only my suppositions... I can't find a useful documentation that explain where is the better function to perform setup operations.
What do you think about that?
The reason you don't find any documentation on where to set up your NSViews is probably that you can set up views, add subviews, etc. in pretty much any method, as long as it is called on the main thread.
For simple apps, applicationDidFinishLaunching: of the application delegate is a useful place.
When the app grows, you might want to consider doing this lazily, when a new window is opened or when a view is added.
For normal apps, you won't need to do anything in viewWillMoveToSuperview/viewDidMoveToSuperview.
I have a custom graphic that is to be displayed to a user when an event occurs. The graphic needs to be displayed on whichever viewController is currently being displayed to the user.
The way i have programmed it so far is by adding to ALL viewcontrtollers:
1) the .h file for the custom graphic class
2) an observer for the NSNotification event that is raised
3) the method which actually draws the graphic.
This doesnt feel like a very efficient way of doing things and i was wondering if anyone has a better way of doing things?
To me it sounds like you've done it in a fairly sane way. The only other way I can think is to just add the graphic to the window which would then overlay on the current view controller and you'd only need to have one object listening for the notification. You could use the app delegate for instance. But then you would have to worry about rotation of the screen yourself when adding the graphic over the top.
What you are doing is correct .. The only thing you can improve is to mauve the drawing graphics part to the custom graphic class.. (if you are not already doing so...
just Make a UIViewController variable as a member variable to the graphics class..and then set it up to the current view displaying..after you receive the notifications..and the class will itself draw the code based on the ViewController you set it up to
The reason it doesn't feel efficient is that you're duplicating a lot of code. That's more work at the outset, and it creates a maintenance headache. You should be taking advantage of the inheritance that's built into object oriented languages, including Objective-C.
If you want all your view controllers to share some behavior, then implement that behavior in a common superclass. Derive all your other view controllers from that superclass, and they'll all automatically get the desired behavior. Your superclass's initializer can take care of registering the view controller for the notification(s) that you care about, and -dealloc can unregister it. This way, you don't have to clutter up each view controller with the same repeated code, and if you want to change the code you only have to do it in one place.
I'm writing a program for iPhone that will first let the user take a photo, then will dynamically retrieve a colour of the place where the user taps on the image, and draw a rectangle of that colour. I have two relevant classes for this: AppViewController and AppView. The former contains all the UI elements and IBActions, the latter the position of last tap, the touches-handling methods and the drawRect (and a static method to get colour data at a given coords of an image).
What I wanted to do is to put the touch-handling (calling drawRect in touchesMoved/Ended) and the drawRect in the AppViewController. That doesn't work, since that class doesn't inherit from UIView, but from UIViewController. What's the correct way to do that?
Another way to phrase that: How to constantly change something (well, constantly as long as the user is swiping across the screen) in a class that doesn't support touch-detection methods?
(This probably doesn't explain it well. Please ask clarifying questions).
I think the delegate pattern might be helpful to you in this situation. You could call your delegate's shouldUpdateRectangle selector in touchesMoved/Ended.
There is not really a correct way to move the view's behaviors into a view controller, since that is not the way the classes are meant to be used. You should probably look at what's driving you to try to subvert the framework's design this way, because that is likely going to be easier to fix.
It's not uncommon, though, for a view to call out to a supporting class for help in this stuff. You could certainly have your view's drawRect: call methods in the view controller, though I would be careful about mixing their concerns too much, because it could get hard to figure out who's responsible for what.
I'm slowly learning Objective-C and Cocoa, and the only way I see so far to capture key events in Text Views is to use delegation, but I'm having trouble finding useful documentation and examples on how to implement such a solution. Can anyone point me in the right direction or supply some first-hand help?
Generally, the way you implement it is simply to add the required function to your view's controller, and set its delegate. For example, if you want code to run when the view loads, you just delegate your view to the controller, and implement the awakeFromNib function.
So, to detect a key press in a text view, make sure your controller is the text view's delegate, and then implement this:
- (void)keyUp:(NSEvent *)theEvent
Note that this is an inherited NSResponder method, not a NSTextView method.
Just a tip for syntax highlighting:
Don't highlight the whole text view at once - it's very slow. Also don't highlight the last edited text using -editedRange - it's very slow too if the user pastes a large body of text into the text view.
Instead you need to highlight the visible text which is done like this:
NSRect visibleRect = [[[textView enclosingScrollView] contentView] documentVisibleRect];
NSRange visibleRange = [[textView layoutManager] glyphRangeForBoundingRect:visibleRect inTextContainer:[textView textContainer]];
Then you feed visibleRange to your highlighting code.
It's important to tell us what you're really trying to accomplish — the higher-level goal that you think capturing key events in an NSTextView will address.
For example, when someone asks me how to capture key events in an NSTextField what they really want to know is how to validate input in the field. That's done by setting the field's formatter to an instance of NSFormatter (whether one of the formatters included in Cocoa or a custom one), not by processing keystrokes directly.
So given that example, what are you really trying to accomplish?
I've done some hard digging, and I did find an answer to my own question. I'll get at it below, but thanks to the two fellas who replied. I think that Stack Overflow is a fantastic site already--I hope more Mac developers find their way in once the beta is over--this could be a great resource for other developers looking to transition to the platform.
So, I did, as suggested by Danny, find my answer in delegation. What I didn't understand from Danny's post was that there are a set of delegate-enabled methods in the delegating object, and that the delegate must implement said events. And so for a TextView, I was able to find the method textDidChange, which accomplished what I wanted in an even better way than simply capturing key presses would have done. So if I implement this in my controller:
- (void)textDidChange:(NSNotification *)aNotification;
I can respond to the text being edited. There are, of course, other methods available, and I'm excited to play with them, because I know I'll learn a whole lot as I do. Thanks again, guys.