I am noob to XCode and Obj-C world, so pardon me for my naive question.
Following a tutorial, I was writing a basic program in Cocos2D that would accept touch input.
And one of the task was to add implement ccTouchBegan method, but that would not show up in XCode's code sense.
I wanted to implement this method
-(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event
but I would find only this one (related to touch began)
-(BOOL) ccTouchesBeganWithEvent:(*)event
Now that I a noob, how do I explore list of all available methods and properties for a particular Class?
The image shows list of available methods that starts with ccT. ccTouchBegan and ccTouchEnded showed up because I have implemented them already. Else, they would not show just like ccTouchCancelled and ccTouchMoved events didn't show up.
How do I see all available methods & properties of a Class or Object?
To see all the available methods & properties just press Ctrl+Space
Option+Click on the object (in this case, that would be the delegate name in the header file between the < >). A small help popup will appear. Click the blue text inside the popup and the Organizer window will open at the documentation for the Class. The Documentation has all methods and properties you can use.
Just press Backspace 3 times to delete the ccT you typed in. The list will increase with every character you erase. The full list not only shows methods, as you will see.
Maybe it does not show up because you have already defined it in your code? That would be logical, as double implementation would lead to a compiler error.
Related
I'm no iOS guru but I know enough to build apps. I know and understand the patterns, UIKit, and Objective-C. I'm now learning Mac Development and this little bit of "Cocoa Bindings Programming Topics" has me stumped:
Take as an example a very simple application in which the values in a text field and a slider are kept synchronized. Consider first an implementation that does not use bindings. The text field and slider are connected directly to each other using target-action, where each is the other’s target and the action is takeFloatValueFrom: as shown in Figure 2. (If you do not understand this, you should read Getting Started With Cocoa.)
This example illustrates the dynamism of the Cocoa environment—the values of two user interface objects are kept synchronized without writing any code, even without compiling.
(Emphasis mine)
Huh? Wouldn't you need to create outlets? And an IBAction that goes something like
- (IBAction)takeFloatValueFrom:(id)sender {
self.slider.floatValue = [sender floatValue];
self.textField.floatValue = [sender floatValue];
}
Is this something Mac-specific? How do you actually hook up two controls with target-action in a XIB without writing any code and have their values locked?
When you're setting up an interface in Interface Builder, you can specify that it sends a message to another object whenever it changes in some way. What this example is showing is that you can hook these two objects up such that whenever the slider changes, it sends the message takeFloatValueFrom: to the text field, and vice-versa.
takeFloatValueFrom: is a method defined on NSControl, and both a text field and a slider are subclasses of NSControl.
i have been working on moving one of my apps away from the "shared appdelegate" process which seems to be frowned up, despite its over whelming use. i have been attempting to setup protocol methods for what i want to do but am having zero luck. my question is, can you even have lets say a single viewcontroller send delegate requests to multiple classes? from what im finding out it doesn't seem like you can. which doesn't make sense because i thought that was the whole point of delegates and protocols with mvc. now just to clarify, i know you can have a single viewcontroller act as the delegate for multiple other viewcontrollers. but that's not what i am asking. for a simple example, lets say you have apples flip-utility template. the "done" button just calls a delegate method to the mainvc to dismiss it. now lets say we added a new class called...
#interface NewClass : NSObject <TheOtherDelegate>
and it had a delegate method...
- (void)doSomething
{
NSLog(#"The Delegate did something...");
}
can we have a button on the flipsideviewcontroller, that we wanted to call that delegate method, but still keep the "done" button call to the delegate method on the mainviewcontroller that dismisses it?
that being said, i put together a quicky project just to see if it would work and it doesn't. i came across an "answer" that says you have to instantiate the class first you want to be the delegate...
NewClass *myDelegate = [NewClass alloc] init]
[fillInMethodHere setDelegate:myDelegate];
not sure why it got a correct answer check, because needless to say it doesn't work. is there something i am missing? i scoured ib to see if there is some "delegate" connection somewhere but i couldn't find anything.
on a side note, as i was working in my working project, i read a suggestion about removing the #import and adding #class. again, that broke all kinds of things. the strange thing is before doing that, what i had so far was working and building fine. when i removed the new #class and un-commented the #import. xcode all of a sudden gave me an error "cannot find protocol deceleration for..." but yet, it worked seconds earlier. i would up having to remove the protocol code and re-add it for it to work again. very starge.
any help would be appreciated. everything iv read in docs, google, stack, etc that say something should work, don't in an actual project.
A "delegate" isn't some fancy object. It's simply a synthesized property of type id called delegate. If you wanted to, you could have an arbitrary number of properties that all conformed to the same protocol. Then when you wanted to issue a callback, you would just address all of them:
[self.mydelegateA doSomething];
[self.mydelegateB doSomething];
etc.
You could also have an NSMutableArray property that you could add objects to, and then use [self.myMutableArrayOfDelegates makeObjectsPerformSelector:#selector(doSomething)].
Finally, there's always the route of NSNotificationCenter (not to be confused with push notifications) is a class that provides an inter-object messaging system. Many objects can register for a message that any other object can send.
Please see the Apple's documentation for more information. Click Here.
Regardless of the fact that this is OS X documentation, it's still quite good at explaining things visually: click here.
Here's an example of simply changing the name of the delegate property: click here
And here's an example of adding another protocol and a second delegate: click here
Finally, here's an example that builds on the previous two and has a third delegate that also conforms to the same protocol: click here
I'm a complete programming novice and I was wondering how I could have several buttons that play different sounds. I've searched all around and can't figure out this simple task. Thanks!
It's a simple task once you know enough about Objective-C and the Cocoa (Cocoa-Touch on iPhone) frameworks.
Rather than just searching the net for examples you would be better off looking for references on how to program Objective-C and Cocoa.
The steps are:
In Xcode, create a controller class that has a method such as this: - (IBAction)playSound:(id)sender;
Create the UI using Interface Builder.
Place the buttons you want on this interface and configure their labels.
For each of the buttons set a numeric tag (you can do this in interface builder).
For each of the buttons set the target to be the controller and the action to be the method you created in step 1. (You do this by ctrl dragging the button onto the controller object in Interface Builder)
In the controller class, fill out the method by writing a for loop that checks the tag of of the button (which you can get through the 'sender' object and then play a sound based on the tag.
Depending on your level of experience with Cocoa, this might not make sense right now, but if you read through the references and tutorials for Objective-C and Cocoa each of these steps will become clearer and you'll be able to complete this simple task yourself.
Just wondering, how I go about detecting different keystrokes, and then detecting what key has been pressed I tried using this,
-(void)keyDown:(NSEvent *)event
but didnt seem to get any results. I've also had a search around but didn't find anything. I'm guessing I may have to set up something in interface builder to detect keystrokes?
I also think that it has something to do with what is selected, if its a text field something.
keyDown: method is called only for certain view and it's subviews I think. If you need all keystrokes for your app - check NSEvent class method:
+ (id)addLocalMonitorForEventsMatchingMask:(NSEventMask)mask
handler:(NSEvent* (^)(NSEvent*))block
Read upon in it Xcode documentation. I presume you're on snow leopard.
I tried using this, - (void)keyDown:(NSEvent *)event but didnt seem to get any results.
What do you mean “using” it?
You need one of your objects to respond to that message. That means you need it to be a responder, and to be in the responder chain whenever it is appropriate for the keystrokes it handles to be pressed.
Depending on what the keypress does, it may be appropriate for a single custom view to handle it; if not, it should probably be the window controller that handles it. Either one should already be in the responder chain at the appropriate times. Whichever way you go, you'll need to subclass either NSView (for a custom view) or NSWindowController.
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.