iPhone UIImageView動畫難題

Question

我在使用UIImageView動畫時遇到了一些問題。 我創建了三個包含圖像的NSArray對象，並創建了三個采用UIImageView並為其分配新動畫的方法。 它第一次調用三種方法中的一種非常有效，但是另一次它會使模擬器和設備崩潰。 有任何想法嗎？

// 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];
}

日志錯誤：

[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

我認為你需要retain你在viewDidLoad創建的三個數組 - 你永遠不會在它們上調用alloc ，所以在你調用retain之前你沒有所有權。

Answer 2

而不是只調用retain使用initWithObjects消息：

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

Answer 3

但是，如果您按照Lounges的建議行事，請注意您需要稍后釋放slowAnimation對象。 因為你分配了它，它的保留計數為1，直到有人告訴運行時。