iPhone UIImageView动画难题

Question

I'm having some problems with UIImageView animations. I've created three NSArray objects containing the images and created three methods that take a UIImageView and assigns the new animations to it. It works fantastic calling one of the three methods the first time but doing it another time crashes the simulator and device. Any Ideas?

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {

// set the anims
slowAnimation = [NSArray arrayWithObjects:
                    [UIImage imageNamed:@"image1.jpg"],
                    [UIImage imageNamed:@"image2.jpg"],
                                nil];
defaultAnimation = [NSArray arrayWithObjects:
                    [UIImage imageNamed:@"image3.jpg"],
                    [UIImage imageNamed:@"image4.jpg"],
                        nil];
fastAnimation = [NSArray arrayWithObjects:
                    [UIImage imageNamed:@"image5.jpg"],
                    [UIImage imageNamed:@"image6.jpg"],
                    nil];

// load the default speed - this works once, but when applied a second time it crashes the simulator and device
[self setDefaultAnim:myUIImageViewObject];

[super viewDidLoad];
}


// animation switcher
-(void)setSlowAnim:(UIImageView *)imageView
{
    [imageView stopAnimating];
    imageView.animationImages = slowAnimation;
    imageView.animationDuration = 0.4;
    [imageView startAnimating];
}
-(void)setDefaultAnim:(UIImageView *)imageView
{
    [imageView stopAnimating];
    imageView.animationImages = defaultAnimation;
    imageView.animationDuration = 0.4;
        [imageView startAnimating];
}
-(void)setFastAnim:(UIImageView *)imageView
{
    [imageView stopAnimating];
    imageView.animationImages = fastAnimation;
    imageView.animationDuration = 0.4;
   [imageView startAnimating];
}

Error in log:

[Session started at 2009-04-06 22:46:54 +0100.]
Loading program into debugger…
GNU gdb 6.3.50-20050815 (Apple version gdb-962) (Sat Jul 26 08:14:40 UTC 2008)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-apple-darwin".warning: Unable to read symbols for "/System/Library/Frameworks/UIKit.framework/UIKit" (file not found).
warning: Unable to read symbols from "UIKit" (not yet mapped into memory).
warning: Unable to read symbols for "/System/Library/Frameworks/CoreGraphics.framework/CoreGraphics" (file not found).
warning: Unable to read symbols from "CoreGraphics" (not yet mapped into memory).
Program loaded.
sharedlibrary apply-load-rules all
Attaching to program: `/Users/hello/Library/Application Support/iPhone Simulator/User/Applications/6DB7C45D-1A26-4775-9AE3-C30F3EBC9F83/PlateSpinner.app/PlateSpinner', process 345.
kill
quit

The Debugger has exited with status 0.

Answer 1

我认为你需要retain你在viewDidLoad创建的三个数组 - 你永远不会在它们上调用alloc ，所以在你调用retain之前你没有所有权。

Answer 2

Instead of just calling retain use the initWithObjects message:

slowAnimation = [[NSArray alloc] initWithObjects:
                                  [UIImage imageNamed:@"image1.jpg"],
                                  [UIImage imageNamed:@"image2.jpg"],
                                  nil];

Answer 3

If you do what Lounges suggests, though, note that you will need to later release the slowAnimation object. Since you alloc'd it, it will have a retain count of 1 until someone tells the runtime otherwise.