ios - 还有一个 EXC_BAD_ACCESS，不知道为什么

Question

我有一个 ScrollView ，它是我的主视图的 subview 。当显示时，此 ScrollView 显示 8 个 subview ，其中 3 个在屏幕上随时可见。用户可以向左/向右滚动来查看它们，然后点击进行选择。

一旦做出选择，我就会检查所选对象是否与当前选择相同，如果不同，则释放当前对象并保留新对象。如果它们相同，那么我什么也不做。

当我为 ScrollView 创建 8 个 subview 时，我一次创建一个 subview ，然后将其添加到 subview 中，然后释放。我认为由于 View 保留了副本，因此我不需要副本。现在我怀疑这可能是我的问题，但我真的不明白为什么，因为一切似乎都正常(很好)。无论如何...

我需要指出，这 8 个 subview 是 UIImageView 的子类。这样每个人都可以改变自己的 Alpha，使其在移过屏幕中心时显得稍微褪色。出现在中心的对象会将其 Alpha 更改为 100% 不透明。

这是相关代码...

ScrollView 的接口(interface):

@interface RootViewController : UIViewController <UIScrollViewDelegate, thumbViewDelegate>  {
        id<RootViewControllerDelegate>  _delegate
        PagingScrollView *thumbScrollView;
        ChairPart *selectedChairPart;

}

@property (nonatomic, retain) PagingScrollView *thumbScrollView;
@property (nonatomic, retain) ChairPart *selectedChairPart;

ScrollView 的实现(selectedChairPart在viewDidLoad中初始化):

@synthesize selectedChairPart;
@synthesize thumbScrollView;

- (void)createThumbScrollViewIfNecessary {


if (![self thumbScrollView]) {        
    self.m_pageControl.currentPage = 1;
    float scrollViewHeight = THUMB_HEIGHT;
    float scrollViewWidth  = THUMB_WIDTH;


    self.thumbScrollView = [[PagingScrollView alloc] initWithFrame:CGRectMake(234, 5, scrollViewWidth, scrollViewHeight)];
    [[self thumbScrollView] setCanCancelContentTouches:NO];
    [[self thumbScrollView] setClipsToBounds:NO];
    [[self thumbScrollView] setDelegate:self];
    [[self thumbScrollView] setShowsHorizontalScrollIndicator:NO];
    [[self thumbScrollView] setShowsVerticalScrollIndicator:NO];
    [[self thumbScrollView] setPagingEnabled:YES];


    // now place all the thumb views as subviews of the scroll view 
    // and in the course of doing so calculate the content width
    float xPosition = 0; 

    id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:0];
    int count = [sectionInfo numberOfObjects];
    NSIndexPath *indexPath = nil;

    for (int i = 0; i < count; i++) {
        indexPath = [NSIndexPath indexPathForRow: i  inSection: 0];
        ChairPart *part = [fetchedResultsController objectAtIndexPath:indexPath ];  


        UIImage *thumbImage = [UIImage imageNamed:[NSString stringWithFormat:@"%@", [part icon]]];
        if (thumbImage) {

            ThumbView *thumbView = [[ThumbView alloc] initWithImage:thumbImage];
            [thumbView setDelegate:self];

            [thumbView setChairPart:part];

            [thumbView setAlpha:0.50f];
            if (i == 0) {
                [thumbView setAlpha:1.0];
            }

            CGRect frame = [thumbView frame];
            frame.origin.y = THUMB_V_PADDING;
            frame.origin.x = xPosition;
            frame.size.width += 100;
            [thumbView setFrame:frame];
            [thumbView setTag:555 + i];
            xPosition += frame.size.width;

            [[self thumbScrollView] addObserver:thumbView 
                              forKeyPath:@"contentOffset" 
                                 options:NSKeyValueObservingOptionNew
                                 context:@selector(updateAlpha:)];          


            [[self thumbScrollView] addSubview:thumbView];
            [thumbView release];
        }

    }

    [[self thumbScrollView] setContentSize:CGSizeMake(xPosition, scrollViewHeight)];

    }  
}

点击/选定图像的实现:

- (void)thumbViewWasTapped:(ThumbView *)tiv {
    NSLog(@"------------thumbview Tapped-----------------------");

    NSLog(@"from:%p to:%p",[self selectedChairPart], [tiv chairPart]);

    if ([self selectedChairPart] != [tiv chairPart]) {
        if ([self selectedChairPart] != nil) {
            [selectedChairPart release];
        } else {
            NSLog(@"selectedChairPart is NIL!!!!!!!!!!");
        }


        if (tiv == nil)  {
            NSLog(@"------TIV = NILLLLL");
        }
        NSLog(@"tiv is:%@", tiv);
    // crash happens on the next line...
        [self setSelectedChairPart:[tiv chairPart]];




    } else {
        NSLog(@"chairparts identical");
    }

    [self toggleThumbView];
}

缩略图界面:

@class ChairPart;

@protocol ThumbViewDelegate;


@interface ThumbView : UIImageView {
    id <ThumbViewDelegate> delegate;

ChairPart *chairPart;
UIImageView *iconView;
CGPoint touchLocation; // Location of touch in own coordinates (stays constant during dragging).
}

@property (nonatomic, assign) id <ThumbViewDelegate> delegate;
@property (nonatomic, retain) UIImageView *iconView;
@property (nonatomic, retain) ChairPart *chairPart;
@property (nonatomic, assign) CGPoint touchLocation;

@end

@protocol ThumbViewDelegate <NSObject>

@optional
- (void)thumbViewWasTapped:(ThumbView *)tiv;
- (void)thumbViewStartedTracking:(ThumbView *)tiv;
- (void)thumbViewStoppedTracking:(ThumbView *)tiv;

@end

缩略图的实现:

float distanceBetweenPoints(CGPoint a, CGPoint b);

@implementation ThumbView

@synthesize delegate;
@synthesize touchLocation;
@synthesize chairPart;
@synthesize iconView;

- (id)initWithImage:(UIImage *)image {
    CGSize size = [image size];
    CGRect rect = CGRectMake(0, 0, size.width, size.height);    
    self = [super initWithFrame:rect];

    UIImageView *myImageView = [[UIImageView alloc] initWithImage:image];
    self.iconView = myImageView;

    CGRect frame = [myImageView frame];
    frame.origin.x += 50;
    [self.iconView setFrame:frame];



    [self addSubview:self.iconView];
    [myImageView release];
    if (self) {
        [self setUserInteractionEnabled:YES];

    }
    return self;
}



- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    // store the location of the starting touch so we can decide when we've moved far enough to drag
    touchLocation = [[touches anyObject] locationInView:self];
    if ([delegate respondsToSelector:@selector(thumbViewStartedTracking:)])
        [delegate thumbViewStartedTracking:self];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([[touches anyObject] tapCount] == 1) {
        CGFloat alpha = [self alpha];
        if (alpha > 0.31) {
            if ([delegate respondsToSelector:@selector(thumbViewWasTapped:)])
                [delegate thumbViewWasTapped:self];
        }
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([delegate respondsToSelector:@selector(thumbViewStoppedTracking:)]) 
        [delegate thumbViewStoppedTracking:self];
}

- (void)observeValueForKeyPath:(NSString *)keyPath 
                      ofObject:(id)object 
                        change:(NSDictionary *)change 
                       context:(void *)context {
    if ([object isKindOfClass:[PagingScrollView class]]) {
        PagingScrollView *parentView = (PagingScrollView *)object; 
        if ( (parentView != nil) && ([parentView alive]) ) {
            [self performSelector:(SEL)context withObject:change];
        } else {
            [parentView removeObserver:self forKeyPath:@"contentOffset"];
        }
    }


}

- (void)updateAlpha:(NSDictionary *)change {
//  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    CGFloat offset = [[change objectForKey:NSKeyValueChangeNewKey] CGPointValue].x;
    CGFloat origin = [self frame].origin.x;
    CGFloat delta = fabs(origin - offset);
    CGFloat mod = 1 - delta/self.frame.size.width;

    [UIView beginAnimations:@"Fading" context:nil];
    if (delta < [self frame].size.width) {
        self.alpha = mod * 0.7 + .2;
        [self _iconView].transform = CGAffineTransformMakeScale(mod * 1.0 + 0.5, mod * 1.0 + 0.5);
    } else {
        mod = delta/self.frame.size.width;
        [self _iconView].transform = CGAffineTransformMakeScale(mod * 1.0 - 0.5, mod * 1.0 - 0.5);

        self.alpha = 0.3;
    }
    [UIView commitAnimations];
//  [pool drain];
}

- (void)dealloc {

    NSLog(@"ThumView dealloc");
    [iconView release];
    [chairPart release];
    [super dealloc];

}


@end

float distanceBetweenPoints(CGPoint a, CGPoint b) {
    float deltaX = a.x - b.x;
    float deltaY = a.y - b.y;
    return sqrtf( (deltaX * deltaX) + (deltaY * deltaY) );
}

我认为没有必要将缩略图存储在数组中，因为 ScrollView 保留每个缩略图的副本，并且选定的缩略图也保留一个副本。我设置了一堆 nslog 语句，检查导致崩溃的行的位置，并显示执行中不同点的变量/对象的内容。

我想也许我只是做错了什么，希望这里有人能指出来。我无法通过构建和分析或泄漏性能找到任何东西。

预先感谢您的帮助。

这是控制台输出:

2011-04-25 07:07:02.444 iRocker[45162:207] ------------thumbview Tapped-----------------------
2011-04-25 07:07:02.445 iRocker[45162:207] from:0x0 to:0x5a62bd0
2011-04-25 07:07:02.446 iRocker[45162:207] selectedChairPart is NIL!!!!!!!!!!
2011-04-25 07:07:02.448 iRocker[45162:207] tiv is:<ThumbView: 0x5a83cd0; baseClass = UIImageView; frame = (0 10; 301 351); alpha = 0.9; tag = 555; layer = <CALayer: 0x5a83ed0>>
2011-04-25 07:07:15.601 iRocker[45162:207] ------------thumbview Tapped-----------------------
2011-04-25 07:07:15.602 iRocker[45162:207] from:0x5a62bd0 to:0x5a62f20
2011-04-25 07:07:15.603 iRocker[45162:207] tiv is:<ThumbView: 0x5a85ef0; baseClass = UIImageView; frame = (301 10; 301 351); alpha = 0.9; tag = 556; layer = <CALayer: 0x5a867d0>>
2011-04-25 07:07:23.618 iRocker[45162:207] ------------thumbview Tapped-----------------------
2011-04-25 07:07:23.619 iRocker[45162:207] from:0x5a62f20 to:0x5a62bd0
2011-04-25 07:07:23.620 iRocker[45162:207] tiv is:<ThumbView: 0x5a83cd0; baseClass = UIImageView; frame = (0 10; 301 351); alpha = 0.9; tag = 555; layer = <CALayer: 0x5a83ed0>>
2011-04-25 07:07:23.620 iRocker[45162:207] *** -[NSConcreteNotification retain]: message sent to deallocated instance 0x5a62bd0
(gdb) bt
#0  0x013bd057 in ___forwarding___ ()
#1  0x013bcf22 in __forwarding_prep_0___ ()
#2  0x015ab7f6 in objc_setProperty ()
#3  0x00007ad9 in -[RootViewController setSelectedChairPart:] (self=0x5a1b4c0, _cmd=0x4375d, _value=0x5a62bd0) at /Users/smorrison/Desktop/Val sample code/ChairBuilder2/Classes/RootViewController.mm:77
#4  0x0000905d in -[RootViewController thumbViewWasTapped:] (self=0x5a1b4c0, _cmd=0x439c4, tiv=0x5a83cd0) at /Users/smorrison/Desktop/Val sample code/ChairBuilder2/Classes/RootViewController.mm:1088
#5  0x000142f9 in -[ThumbView touchesEnded:withEvent:] (self=0x5a83cd0, _cmd=0x77c0e2, touches=0xfa4c080, event=0xfa4bfc0) at /Users/smorrison/Desktop/Val sample code/ChairBuilder2/Classes/ThumbView.m:61
#6  0x005f2987 in _UIGestureRecognizerSortAndSendDelayedTouches ()
#7  0x005f30fc in _UIGestureRecognizerUpdateObserver ()
#8  0x0142cfbb in __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ ()
#9  0x013c20e7 in __CFRunLoopDoObservers ()
#10 0x0138abd7 in __CFRunLoopRun ()
#11 0x0138a240 in CFRunLoopRunSpecific ()
#12 0x0138a161 in CFRunLoopRunInMode ()
#13 0x01d80268 in GSEventRunModal ()
#14 0x01d8032d in GSEventRun ()
#15 0x0037642e in UIApplicationMain ()
#16 0x00002ae4 in main (argc=1, argv=0xbfffef7c) at /Users/smorrison/Desktop/Val sample code/ChairBuilder2/main.m:14

Answer 1

解决方案是删除该行:

       [selectedChairPart release];

来自 ThumbViewWasTapped 方法。我认为这会导致泄漏，因为该属性使用保留。它不会导致泄漏，崩溃也消失了。

我真的很想了解这是如何解决的，但这没有意义。如有任何意见，我们将不胜感激。