我有一个scrollview，它是我主视图的子视图。显示时，此滚动视图显示8个子视图，其中3个在任何时候都可在屏幕上看到。用户可以向左/向右滚动查看它们，然后点击进行选择。
一旦做出选择，我会查看所选对象是否与当前选择相同，如果没有，则释放当前对象并保留新对象。如果他们是相同的，那么我什么都不做。
当我为我的scrollview创建8个子视图时，我一次创建它们，广告到子视图，然后发布。我认为，因为视图保留了副本，所以我不需要副本。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在起作用（好吧）。总之...
我需要指出的是，8个子视图是UIImageViews的子类。这样每个人都可以改变自己的alpha，当它移过屏幕中心时会略微褪色。出现在中心的对象会将其alpha值更改为100％不透明。
以下是相关代码......
滚动视图的界面：
@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（在viewDidLoad中初始化的selectedChairPart）：
@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)];
}
}
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];
}
拇指视图的界面：
@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
拇指视图的实现：
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thumbviews存储在数组中，因为scrollview会保留每个的副本，并且所选的thumbview也会保留副本。我设置了一堆nslog语句，检查导致崩溃的行的位置，并在执行的不同点显示变量/对象的内容。
我想也许我只是做错了什么，希望有人可以指出来。我无法通过构建和发现找到任何东西。分析或泄漏性能。
提前感谢您的帮助。
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
答案 0 :(得分：1)
解决方案是删除该行：
[selectedChairPart release];
。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，崩溃也就消失了。
我真的很想了解这是如何解决的，它只是没有意义。任何评论将不胜感激。