我实现的解决方案确实使用队列。这里有一个非常完整的描述：
这一切都在一个名为PlayerView的视图类中完成。在报头中我包括以下内容：
#import "NSMutableArray+QueueAdditions.h"
@interface PlayerView : UIImageView {
Player* representedPlayer; // The model object represented by the view
NSMutableArray* actionQueue; // An array used as a queue for the actions
bool animatingPlayer; // Notes if the player is in the middle of an animation
bool stoppingAnimation; // Notes if all animations should be stopped (e.g., for re-setting the game)
CGFloat actionDuration; // A convenient way for me to change the duration of all animations
// ... Removed other variables in the class (sound effects, etc) not needed for this example
}
// Notifications
+ (NSString*) AnimationsDidStopNotification;
@property (nonatomic, retain) Player* representedPlayer;
@property (nonatomic, retain, readonly) NSMutableArray* actionQueue;
@property (nonatomic, assign) CGFloat actionDuration;
@property (nonatomic, assign) bool animatingPlayer;
@property (nonatomic, assign) bool stoppingAnimation;
// ... Removed other properties in the class not need for this example
- (void)placePlayer; // puts view where needed (according to the model) without animation
- (void)moveEventHandler:(NSNotification *) notification; // handles events when the player moves
- (void)rotateEventHandler:(NSNotification *) notification; // handles events when the player rotates
// ... Removed other action-related event handles not needed for this example
// These methods actually perform the proper animations
- (void) doMoveAnimation:(CGRect) nextFrame;
- (void) doRotateAnimation:(CGRect)nextFrame inDirection:(enum RotateDirection)rotateDirection;
// ... Removed other action-related methods not needed for this example
// Handles things when each animation stops
- (void) animationDidStop:(NSString*)animationID
finished:(BOOL)finished
context:(void*)context;
// Forces all animations to stop
- (void) stopAnimation;
@end
顺便说一句，在的NSMutableArray + QueueAdditions.h /米QueueAdditions类别看起来像这样：
@interface NSMutableArray (QueueAdditions)
- (id)popObject;
- (void)pushObject:(id)obj;
@end
@implementation NSMutableArray (QueueAdditions)
- (id)popObject
{
// nil if [self count] == 0
id headObject = [self objectAtIndex:0];
if (headObject != nil) {
[[headObject retain] autorelease]; // so it isn't dealloc'ed on remove
[self removeObjectAtIndex:0];
}
return headObject;
}
- (void)pushObject:(id)obj
{
[self addObject: obj];
}
@end
接着，在PlayerView的实施，我有以下几点：
#import "PlayerView.h"
#import <QuartzCore/QuartzCore.h>
@implementation PlayerView
@synthesize actionQueue;
@synthesize actionDuration;
@synthesize animatingPlayer;
@synthesize stoppingAnimation;
// ... Removed code not needed for this example (init to set up the view's image, sound effects, actionDuration, etc)
// Name the notification to send when animations stop
+ (NSString*) AnimationsDidStopNotification
{
return @"PlayerViewAnimationsDidStop";
}
// Getter for the representedPlayer property
- (Player*) representedPlayer
{
return representedPlayer;
}
// Setter for the representedPlayer property
- (void)setRepresentedPlayer:(Player *)repPlayer
{
if (representedPlayer != nil)
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
[representedPlayer release];
}
if (repPlayer == nil)
{
representedPlayer = nil;
// ... Removed other code not needed in this example
}
else
{
representedPlayer = [repPlayer retain];
if (self.actionQueue == nil)
{
actionQueue = [[NSMutableArray alloc] init];
}
[actionQueue removeAllObjects];
animatingPlayer = NO;
stoppingAnimation = NO;
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(moveEventHandler:)
name:[Player DidMoveNotification]
object:repPlayer ];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(rotateEventHandler:)
name:[Player DidRotateNotification]
object:repPlayer ];
// ... Removed other addObserver actions and code not needed in this example
}
}
// ... Removed code not needed for this example
- (void) placePlayer
{
// Example not helped by specific code... just places the player where the model says it should go without animation
}
// Handle the event noting that the player moved
- (void) moveEventHandler: (NSNotification *) notification
{
// Did not provide the getRectForPlayer:onMazeView code--not needed for the example. But this
// determines where the player should be in the model when this notification is captured
CGRect nextFrame = [PlayerView getRectForPlayer:self.representedPlayer onMazeView:self.mazeView];
// If we are in the middle of an animation, put information for the next animation in a dictionary
// and add that dictionary to the action queue.
// If we're not in the middle of an animation, just do the animation
if (animatingPlayer)
{
NSDictionary* actionInfo = [NSDictionary dictionaryWithObjectsAndKeys:
[NSValue valueWithCGRect:nextFrame], @"nextFrame",
@"move", @"actionType",
@"player", @"actionTarget",
nil];
[actionQueue pushObject:actionInfo];
}
else
{
animatingPlayer = YES; // note that we are now doing an animation
[self doMoveAnimation:nextFrame];
}
}
// Handle the event noting that the player rotated
- (void) rotateEventHandler: (NSNotification *) notification
{
// User info in the notification notes the direction of the rotation in a RotateDirection enum
NSDictionary* userInfo = [notification userInfo];
NSNumber* rotateNumber = [userInfo valueForKey:@"rotateDirection"];
// Did not provide the getRectForPlayer:onMazeView code--not needed for the example. But this
// determines where the player should be in the model when this notification is captured
CGRect nextFrame = [PlayerView getRectForPlayer:self.representedPlayer onMazeView:self.mazeView];
if (animatingPlayer)
{
NSDictionary* actionInfo = [NSDictionary dictionaryWithObjectsAndKeys:
[NSValue valueWithCGRect:nextFrame], @"nextFrame",
@"rotate", @"actionType",
rotateNumber, @"rotateDirectionNumber",
@"player", @"actionTarget",
nil];
[actionQueue pushObject:actionInfo];
}
else
{
enum RotateDirection direction = (enum RotateDirection) [rotateNumber intValue];
animatingPlayer = YES;
[self doRotateAnimation:nextFrame inDirection:direction];
}
}
// ... Removed other action event handlers not needed for this example
// Perform the actual animation for the move action
- (void) doMoveAnimation:(CGRect) nextFrame
{
[UIView beginAnimations:@"Move" context:NULL];
[UIView setAnimationDuration:actionDuration];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
self.frame = nextFrame;
[UIView commitAnimations];
}
// Perform the actual animation for the rotate action
- (void) doRotateAnimation:(CGRect)nextFrame inDirection:(enum RotateDirection)rotateDirection
{
int iRot = +1;
if (rotateDirection == CounterClockwise)
{
iRot = -1;
}
[UIView beginAnimations:@"Rotate" context:NULL];
[UIView setAnimationDuration:(3*actionDuration)];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
CGAffineTransform oldTransform = self.transform;
CGAffineTransform transform = CGAffineTransformRotate(oldTransform,(iRot*M_PI/2.0));
self.transform = transform;
self.frame = nextFrame;
[UIView commitAnimations];
}
- (void) animationDidStop:(NSString*)animationID
finished:(BOOL)finished
context:(void *)context
{
// If we're stopping animations, clear the queue, put the player where it needs to go
// and reset stoppingAnimations to NO and note that the player is not animating
if (self.stoppingAnimation)
{
[actionQueue removeAllObjects];
[self placePlayer];
self.stoppingAnimation = NO;
self.animatingPlayer = NO;
}
else if ([actionQueue count] > 0) // there is an action in the queue, execute it
{
NSDictionary* actionInfo = (NSDictionary*)[actionQueue popObject];
NSString* actionTarget = (NSString*)[actionInfo valueForKey:@"actionTarget"];
NSString* actionType = (NSString*)[actionInfo valueForKey:@"actionType"];
// For actions to the player...
if ([actionTarget isEqualToString:@"player"])
{
NSValue* rectValue = (NSValue*)[actionInfo valueForKey:@"nextFrame"];
CGRect nextFrame = [rectValue CGRectValue];
if ([actionType isEqualToString:@"move"])
{
[self doMoveAnimation:nextFrame];
}
else if ([actionType isEqualToString:@"rotate"])
{
NSNumber* rotateNumber = (NSNumber*)[actionInfo valueForKey:@"rotateDirectionNumber"];
enum RotateDirection direction = (enum RotateDirection) [rotateNumber intValue];
[self doRotateAnimation:nextFrame inDirection:direction];
}
// ... Removed code not needed for this example
}
else if ([actionTarget isEqualToString:@"cell"])
{
// ... Removed code not needed for this example
}
}
else // no more actions in the queue, mark the animation as done
{
animatingPlayer = NO;
[[NSNotificationCenter defaultCenter]
postNotificationName:[PlayerView AnimationsDidStopNotification]
object:self
userInfo:[NSDictionary dictionaryWithObjectsAndKeys: nil]];
}
}
// Make animations stop after current animation by setting stopAnimation = YES
- (void) stopAnimation
{
if (self.animatingPlayer)
{
self.stoppingAnimation = YES;
}
}
- (void)dealloc {
if (representedPlayer != nil)
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
[representedPlayer release];
[actionQueue release];
// …Removed other code not needed for example
[super dealloc];
}
@end
说明：
视角子从模型对象（玩家）抄写适当的通知。当捕获通知时，它会检查它是否已经在做动画（使用animatingPlayer属性）。如果是这样，它会从通知中获取信息（注意播放器应该如何动画），将该信息放入字典中，然后将该字典添加到动画队列中。如果当前没有动画，该方法会将animatingPlayer设置为true并调用适当的do [Whatever]动画例程。
每个[无论]动画例程执行适当的动画，将setAnimationDidStopSelector设置为animationDidStop：finished：context :.当每个动画完成时，animationDidStop：finished：context：方法（在检查是否应立即停止所有动画之后）将执行队列中的下一个动画，方法是将下一个字典拖出队列并解释其数据以调用适当做[随时]动画方法。如果队列中没有动画，则该例程将animatingPlayer设置为NO并发布通知，以便其他对象可以知道播放器何时适当地停止了其当前动画的运行。
就是这样。可能有一个更简单的方法（？），但这对我来说工作得很好。如果您有兴趣查看实际结果，请查看我在App Store中的Mazin应用。
谢谢。