I watched the C4 tutorial on adding a pan gesture to an object and animating it to return to its original position when the panning is finished. I'm trying to add this to three individual objects. I have it working with one object so far to move it and reset it to a CGPoint, but for it to work, I have to add the pan gesture to "self", not the object. For reference, I'm pretty much using the code from here:
http://www.c4ios.com/tutorials/interactionPanning
If I add the gesture to the object itself, sure, it pans around, but then it just leaves itself at the last touch location. However, I'm assuming that leaving the gesture on "self" will affect more than just the object I want to move, and I want to be able to move the three objects individually.
I'm using roughly the same modification to the "move" method that's used in the example:
-(void)move:(UIPanGestureRecognizer *)recognizer {
[character move:recognizer];
if (recognizer.state == UIGestureRecognizerStateEnded) {
[character setCenter: charStartOrigin];
}
}
And then a new method to spawn the object:
-(void)createCharacters {
character = [C4Shape ellipse:charStart];
[character addGesture:PAN name:#"pan" action:#"move:"];
[self.canvas addShape:character];
}
The example link you are working from is sneaky. Since I knew that there was only going to be one object on the canvas I knew I could make it look like I was panning the label. This won't work for multiple objects, as you have already figured out.
To get different objects to move independently, and recognize when they are done being dragged, you need to subclass the objects and give them their own "abilities".
To do this I:
Subclass C4Shape
Add custom behaviour to the new class
Create subclassed objects on the canvas
The code for each step looks like the following:
subclassing
You have to create a subclass that gives itself some behaviour. Since you're working with shapes I have done it this way as well. I call my subclass Character, its files look like this:
Character.h
#import "C4Shape.h"
#interface Character : C4Shape
#property (readwrite, atomic) CGPoint startOrigin;
#end
I have added a property to the shape so that I can set its start origin (i.e. the point to which it will return).
Character.m
#import "Character.h"
#implementation Character
-(void)setup {
[self addGesture:PAN name:#"pan" action:#"move:"];
}
-(void)move:(UIGestureRecognizer *)sender {
if(sender.state == UIGestureRecognizerStateEnded) {
self.center = self.startOrigin;
} else {
[super move:sender];
}
}
#end
In a subclass of a C4 object, setup gets called in the same way as it does for the canvas... So, this is where I add the gesture for this object. Setup gets run after new or alloc/init are called.
The move: method is where I want to override with custom behaviour. In this method I catch the gesture recognizer, and if it's state is UIGestureRecognizerStateEnded then I want to animate back to the start origin. Otherwise, I want it to move: like it should so I simply call [super move:sender] which runs the default move: method.
That's it for the subclass.
Creating Subclassed Objects
My workspace then looks like the following:
#import "C4WorkSpace.h"
//1
#import "Character.h"
#implementation C4WorkSpace {
//2
Character *charA, *charB, *charC;
}
-(void)setup {
//3
CGRect frame = CGRectMake(0, 0, 100, 100);
//4
frame.origin = CGPointMake(self.canvas.width / 4 - 50, self.canvas.center.y - 50);
charA = [self createCharacter:frame];
frame.origin.x += self.canvas.width / 4.0f;
charB = [self createCharacter:frame];
frame.origin.x += self.canvas.width / 4.0f;
charC = [self createCharacter:frame];
//5
[self.canvas addObjects:#[charA,charB,charC]];
}
-(Character *)createCharacter:(CGRect)frame {
Character *c = [Character new];
[c ellipse:frame];
c.startOrigin = c.center;
c.animationDuration = 0.25f;
return c;
}
#end
I have added a method to my workspace that creates a Character object and adds it to the screen. This method creates a Character object by calling its new method (I have to do it this way because it is a subclass of C4Shape), turns it into an ellipse with the frame I gave it, sets its startOrigin, changes its animationDuration.
What's going on with the rest of the workspace is this (NOTE: the steps are marked in the code above):
I #import the subclass so that I can create objects with it
I create 3 references to Character objects.
I create a frame that I will use to build each of the new objects
For each object, I reposition frameby changing its origin and then use it to create a new object with the createCharacter: method I wrote.
I add all of my new objects to the canvas.
NOTE: Because I created my subclass with a startOrigin property, I am able within that class to always animate back to that point. I am also able to set that point from the canvas whenever I want.
I have a subclass of CALayer with a custom property, declared as such:
#interface MyLayer : CALayer
#property (nonatomic,retain) NSNumber *customValue;
#end
#implementation MyLayer
#synthesize customValue = _customValue;
#end
I want to animate this property inside of an explicit CATranasction, so i set up a delegate with the actionForLayer:forKey: method implemented which returns an animation, however any changes to someMyLayerInstance.customValue inside of [CATransaction begin] ... [CATransaction end] do not result in actionForLayer:forKey getting called with a corresponding 'key' value.
However, nuking the property on MyLayer and making changes to myLayerInstance by calling setValue:forKey: does result in actionForLayer:forKey: getting called.
It appears that this is because CALayer does some mojo for key/value coding for undefined properties. How can I recreate this mojo so that I can declare properties on MyLayer, but still have them be observed by the animation delegate?
The most important thing is that you need to implement all CALayer accessors using #dynamic. Do not use #synthesize and do not implement the accessors directly. CALayer generates all its own property handlers (as you've indirectly discovered), and you need to let those be used.
You also need to let CALayer know that this property is display-impacting (which you may have already done given your other comments). If you haven't, you do this by implementing +needsDisplayForKey: and returning YES for your key.
Here's an example of a CALayer that animates a custom property (taken from Chapter 7 of iOS 5 Programming Pushing the Limits. The full sample code is available at the Wiley site.) This example implements actionForKey: in the layer, but you can still implement that part in the delegate if you prefer.
#implementation CircleLayer
#dynamic radius;
...
+ (BOOL)needsDisplayForKey:(NSString *)key {
if ([key isEqualToString:#"radius"]) {
return YES;
}
return [super needsDisplayForKey:key];
}
- (id < CAAction >)actionForKey:(NSString *)key {
if ([self presentationLayer] != nil) {
if ([key isEqualToString:#"radius"]) {
CABasicAnimation *anim = [CABasicAnimation
animationWithKeyPath:#"radius"];
anim.fromValue = [[self presentationLayer]
valueForKey:#"radius"];
return anim;
}
}
return [super actionForKey:key];
}
#end
I'm using TTLauncherView as a sort of home screen for my app and I only have one page's worth of icons. How can I make it so the TTLauncherView won't let you drag icons to "the next page"? I want to set a maximum number of pages (in this case one.)
(EDIT: long story short, I subclassed beginEditing, see the answer below.)
I see where why it adds an extra page when beginEditing is called, but I don't want to edit the framework code. (That makes it hard to update to newer versions.) I'd also prefer not to subclass and override that one method, if I have to rely on how it's implemented. (I'm not against subclassing or adding a category if it's clean.)
I tried setting scrollView.scrollEnabled to NO in the callback method launcherViewDidBeginEditing in my TTLauncherViewDelegate, but that doesn't work while it's in editing mode and I don't know why.
I tried adding a blocker UIView to the scrollview to intercept the touch events by setting userInteractionEnabled=NO, which works OK. I still have to disable the dragging of TTLauncherItems to the next page somehow.
I also tried setting the contentSize of the scrollview to it's bounds in launcherViewDidBeginEditing, but that didn't seem to work either.
Is there a better way?
Tried to block gestures:
- (void)setLauncherViewScrollEnabled:(BOOL)scrollEnabled {
if (scrollEnabled) {
[self.scrollViewTouchInterceptor removeFromSuperview];
self.scrollViewTouchInterceptor = nil;
} else {
// iter through the kids to get the scrollview, put a gesturerecognizer view in front of it
UIScrollView *scrollView = [launcherView scrollViewSubview];
self.scrollViewTouchInterceptor = [UIView viewWithFrame:scrollView.bounds]; // property retains it
UIView *blocker = self.scrollViewTouchInterceptor;
[scrollView addSubview:scrollViewTouchInterceptor];
[scrollView sendSubviewToBack:scrollViewTouchInterceptor];
scrollViewTouchInterceptor.userInteractionEnabled = NO;
}
}
For reference: TTLauncherView.m:
- (void)beginEditing {
_editing = YES;
_scrollView.delaysContentTouches = YES;
UIView* prompt = [self viewWithTag:kPromptTag];
[prompt removeFromSuperview];
for (NSArray* buttonPage in _buttons) {
for (TTLauncherButton* button in buttonPage) {
button.editing = YES;
[button.closeButton addTarget:self action:#selector(closeButtonTouchedUpInside:)
forControlEvents:UIControlEventTouchUpInside];
}
}
// Add a page at the end
[_pages addObject:[NSMutableArray array]];
[_buttons addObject:[NSMutableArray array]];
[self updateContentSize:_pages.count];
[self wobble];
if ([_delegate respondsToSelector:#selector(launcherViewDidBeginEditing:)]) {
[_delegate launcherViewDidBeginEditing:self];
}
}
I think overriding beginEditing in TTLauncherView is your best bet. Since you'd only really be touching one method (and only a few lines in that method), upgrading it when the time comes shouldn't be too bad. Since that method explicitly adds the extra page, I'm not sure how you'd get around it w/o editing that specific piece of code
As Andrew Flynn suggested in his answer, I was able to make it work by subclassing and overriding the beginEditing method to remove the extra page TTLauncherView adds when it goes into editing mode.
One problem I'm having is I can't figure out how to remove the warning I get for calling the (private) method updateContentSize on my subclass. I tried casting it to id, but that didn't remove the warning. Is it possible?
edit: I was able to remove the warning by using performSelector to send the message to the private class. (I had previously create a category method performSelector:withInt that wraps NSInvocation so that I can pass primitives via performSelector methods, which makes this very convenient.)
// MyLauncherView.h
#interface MyLauncherView : TTLauncherView {
NSInteger _maxPages;
}
#property (nonatomic) NSInteger maxPages;
#end
// MyLauncherView.m
#implementation MyLauncherView
#synthesize maxPages = _maxPages;
- (void)beginEditing {
[super beginEditing];
// ignore unset or negative number of pages
if (self.maxPages <= 0) {
return;
}
// if we've got the max number of pages, remove the extra "new page" that is added in [super beginEditing]
if ([_pages count] >= self.maxPages ) {
[_pages removeLastObject];
[self updateContentSize:_pages.count]; // this has a compiler warning
// I added this method to NSObject via a category so I can pass primitives with performSelector
// [self performSelector:#selector(updateContentSize:) withInt:_pages.count waitUntilDone:NO];
}
}
I am trying to make a sprite display on the screen in Cocos2d. But, I don't want to use a CCSprite directly. I have a class Unit which will have some additional properties that I will need later on in my game. The class declaration of Unit is as follows:
#interface Unit : CCSprite {
CCSprite *sprite;
}
-(void)init;
#property(nonatomic, retain) NSNumber *type;
#property(nonatomic, retain) CCSprite *sprite;
#end
And my init method for it looks like this:
-(void)init {
self.sprite = [CCSprite spriteWithFile:#"BasicUnit.png"];
self.sprite.position = ccp(50, 100);
}
Now what I need to do is apply it to the screen. So, I have another class called Playscene which is the scene where I want to display sprites and things. Here is what the init method (the method that should draw the sprites) looks like in Playscene:
-(id) init {
if( (self=[super init] )) {
self.isTouchEnabled = YES;
[army init];
[self addChild:army.sprite];
}
return self;
}
But, when I run this I get a ton of error data including: "terminate called after throwing an instance of 'NSException'" and probably of more importance: "Assertion failure in -[PlayScene addChild:]". I don't know how I can solve this. Any help would be appreciated.
Based on your snippets it is very difficult to know what goes wrong. That said I assume that army in your last snipped is of type Unit. But because that is inside the init() method it could be that it is nil because it is not created here like in army = [[Unit] alloc] initXXX];.
That said I am not sure what you want to accomplish with subclassing CCSprite in your Unit class because you are referencing CCSpirit and so there is not need to subclass it.
Finally your Assertion is probably because your army.spirit is either NIL or it is already added and the assertion inside Coco2d throws the exception (I am assuming that the last snippet is from a subclass of CCNode).
My suggestions:
Don't extend CCSpirit in Unit (not needed as far as I can see)
Don't have a method - (void) init but overwrite - (id) init
Make sure army is properly instantiated using [[Unit alloc] init] (see point above)
Using alloc you need to make sure that if it is assigned to a retaining property that you also release it to offset the alloc.
Hope that helps.
I've got a layer with some complex drawing code in its -drawInContext: method. I'm trying to minimize the amount of drawing I need to do, so I'm using -setNeedsDisplayInRect: to update just the changed parts. This is working splendidly. However, when the graphics system updates my layer, it's transitioning from the old to the new image using a cross-fade. I'd like it to switch over instantly.
I've tried using CATransaction to turn off actions and set the duration to zero, and neither work. Here's the code I'm using:
[CATransaction begin];
[CATransaction setDisableActions: YES];
[self setNeedsDisplayInRect: rect];
[CATransaction commit];
Is there a different method on CATransaction I should use instead (I also tried -setValue:forKey: with kCATransactionDisableActions, same result).
You can do this by setting the actions dictionary on the layer to return [NSNull null] as an animation for the appropriate key. For example, I use
NSDictionary *newActions = #{
#"onOrderIn": [NSNull null],
#"onOrderOut": [NSNull null],
#"sublayers": [NSNull null],
#"contents": [NSNull null],
#"bounds": [NSNull null]
};
layer.actions = newActions;
to disable fade in / out animations on insertion or change of sublayers within one of my layers, as well as changes in the size and contents of the layer. I believe the contents key is the one you're looking for in order to prevent the crossfade on updated drawing.
Swift version:
let newActions = [
"onOrderIn": NSNull(),
"onOrderOut": NSNull(),
"sublayers": NSNull(),
"contents": NSNull(),
"bounds": NSNull(),
]
Also:
[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
//foo
[CATransaction commit];
When you change the property of a layer, CA usually creates an implicit transaction object to animate the change. If you do not want to animate the change, you can disable implicit animations by creating an explicit transaction and setting its kCATransactionDisableActions property to true.
Objective-C
[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
// change properties here without animation
[CATransaction commit];
Swift
CATransaction.begin()
CATransaction.setValue(kCFBooleanTrue, forKey: kCATransactionDisableActions)
// change properties here without animation
CATransaction.commit()
In addition to Brad Larson's answer: for custom layers (that are created by you) you can use delegation instead of modifying layer's actions dictionary. This approach is more dynamic and may be more performant. And it allows disabling all implicit animations without having to list all animatable keys.
Unfortunately, it's impossible to use UIViews as custom layer delegates, because each UIView is already a delegate of its own layer. But you can use a simple helper class like this:
#interface MyLayerDelegate : NSObject
#property (nonatomic, assign) BOOL disableImplicitAnimations;
#end
#implementation MyLayerDelegate
- (id<CAAction>)actionForLayer:(CALayer *)layer forKey:(NSString *)event
{
if (self.disableImplicitAnimations)
return (id)[NSNull null]; // disable all implicit animations
else return nil; // allow implicit animations
// you can also test specific key names; for example, to disable bounds animation:
// if ([event isEqualToString:#"bounds"]) return (id)[NSNull null];
}
#end
Usage (inside the view):
MyLayerDelegate *delegate = [[MyLayerDelegate alloc] init];
// assign to a strong property, because CALayer's "delegate" property is weak
self.myLayerDelegate = delegate;
self.myLayer = [CALayer layer];
self.myLayer.delegate = delegate;
// ...
self.myLayerDelegate.disableImplicitAnimations = YES;
self.myLayer.position = (CGPoint){.x = 10, .y = 42}; // will not animate
// ...
self.myLayerDelegate.disableImplicitAnimations = NO;
self.myLayer.position = (CGPoint){.x = 0, .y = 0}; // will animate
Sometimes it's convenient to have view's controller as a delegate for view's custom sublayers; in this case there is no need for a helper class, you can implement actionForLayer:forKey: method right inside the controller.
Important note: don't try to modify the delegate of UIView's underlying layer (e.g. to enable implicit animations) — bad things will happen :)
Note: if you want to animate (not disable animation for) layer redraws, it is useless to put [CALayer setNeedsDisplayInRect:] call inside a CATransaction, because actual redrawing may (and probably will) happen sometimes later. The good approach is to use custom properties, as described in this answer.
Here's a more efficient solution, similar to accepted answer but for Swift. For some cases it will be better than creating a transaction every time you modify the value which is a performance concern as others have mentioned e.g. common use-case of dragging the layer position around at 60fps.
// Disable implicit position animation.
layer.actions = ["position": NSNull()]
See apple's docs for how layer actions are resolved. Implementing the delegate would skip one more level in the cascade but in my case that was too messy due to the caveat about the delegate needing to be set to the associated UIView.
Edit: Updated thanks to the commenter pointing out that NSNull conforms to CAAction.
Actually, I didn't find any of the answers to be the right one. The method that solves the problem for me was this:
- (id<CAAction>)actionForKey:(NSString *)event {
return nil;
}
Then you can whatever logic in it, to disable a specific animation, but since I wanted to removed them all, I returned nil.
Based on Sam's answer, and Simon's difficulties... add the delegate reference after creating the CSShapeLayer:
CAShapeLayer *myLayer = [CAShapeLayer layer];
myLayer.delegate = self; // <- set delegate here, it's magic.
... elsewhere in the "m" file...
Essentially the same as Sam's without the ability to toggle via the custom "disableImplicitAnimations" variable arrangement. More of a "hard-wire" approach.
- (id<CAAction>)actionForLayer:(CALayer *)layer forKey:(NSString *)event {
// disable all implicit animations
return (id)[NSNull null];
// allow implicit animations
// return nil;
// you can also test specific key names; for example, to disable bounds animation:
// if ([event isEqualToString:#"bounds"]) return (id)[NSNull null];
}
To disable implicit layer animations in Swift
CATransaction.setDisableActions(true)
Found out a simpler method to disable action inside a CATransaction that internally calls setValue:forKey: for the kCATransactionDisableActions key:
[CATransaction setDisableActions:YES];
Swift:
CATransaction.setDisableActions(true)
Updated for swift and disabling only one implicit property animation in iOS not MacOS
// Disable the implicit animation for changes to position
override open class func defaultAction(forKey event: String) -> CAAction? {
if event == #keyPath(position) {
return NSNull()
}
return super.defaultAction(forKey: event)
}
Another example, in this case eliminating two implicit animations.
class RepairedGradientLayer: CAGradientLayer {
// Totally ELIMINATE idiotic implicit animations, in this example when
// we hide or move the gradient layer
override open class func defaultAction(forKey event: String) -> CAAction? {
if event == #keyPath(position) {
return NSNull()
}
if event == #keyPath(isHidden) {
return NSNull()
}
return super.defaultAction(forKey: event)
}
}
Add this to your custom class where you are implementing -drawRect() method. Make changes to code to suite your needs, for me 'opacity' did the trick to stop cross-fade animation.
-(id<CAAction>) actionForLayer:(CALayer *)layer forKey:(NSString *)key
{
NSLog(#"key: %#", key);
if([key isEqualToString:#"opacity"])
{
return (id<CAAction>)[NSNull null];
}
return [super actionForLayer:layer forKey:key];
}
If you ever need a very quick (but admittedly hacky) fix it might be worth just doing (Swift):
let layer = CALayer()
// set other properties
// ...
layer.speed = 999
As of iOS 7 there's a convenience method that does just this:
[UIView performWithoutAnimation:^{
// apply changes
}];
To disable the annoying (blurry) animation when changing the string property of a CATextLayer, you can do this:
class CANullAction: CAAction {
private static let CA_ANIMATION_CONTENTS = "contents"
#objc
func runActionForKey(event: String, object anObject: AnyObject, arguments dict: [NSObject : AnyObject]?) {
// Do nothing.
}
}
and then use it like so (don't forget to set up your CATextLayer properly, e.g. the correct font, etc.):
caTextLayer.actions = [CANullAction.CA_ANIMATION_CONTENTS: CANullAction()]
You can see my complete setup of CATextLayer here:
private let systemFont16 = UIFont.systemFontOfSize(16.0)
caTextLayer = CATextLayer()
caTextLayer.foregroundColor = UIColor.blackColor().CGColor
caTextLayer.font = CGFontCreateWithFontName(systemFont16.fontName)
caTextLayer.fontSize = systemFont16.pointSize
caTextLayer.alignmentMode = kCAAlignmentCenter
caTextLayer.drawsAsynchronously = false
caTextLayer.actions = [CANullAction.CA_ANIMATION_CONTENTS: CANullAction()]
caTextLayer.contentsScale = UIScreen.mainScreen().scale
caTextLayer.frame = CGRectMake(playbackTimeImage.layer.bounds.origin.x, ((playbackTimeImage.layer.bounds.height - playbackTimeLayer.fontSize) / 2), playbackTimeImage.layer.bounds.width, playbackTimeLayer.fontSize * 1.2)
uiImageTarget.layer.addSublayer(caTextLayer)
caTextLayer.string = "The text you want to display"
Now you can update caTextLayer.string as much as you want =)
Inspired by this, and this answer.
Try this.
let layer = CALayer()
layer.delegate = hoo // Same lifecycle UIView instance.
Warning
If you set delegate of UITableView instance, sometimes happen crash.(Probably scrollview's hittest called recursively.)