1

我有一个自定义 UISegmentedControl,当我初始化它时,它有时会崩溃。这是不常见的,大约 1% 的时间,(只是罕见到足以通过苹果的“严格”应用程序测试),即使我在其他三个视图中有完全相同的代码,它只会在其中一个特定的视图上崩溃。

代码:

NSArray *providers = [[NSArray alloc] initWithObjects:@"All", @"Soon", @"Attn", @"Late",     @"Done", nil]; //categories for segmented control
FancySegmentedControl *fancy = [[FancySegmentedControl alloc] initWithItems:providers];
fancy.backgroundColor = [UIColor clearColor]; //change bg color
fancy.frame = CGRectMake(11, 86, 263, 29); //lldb crashes here
[fancy setBackgroundColor:[UIColor colorWithRed:42/255.0f
                                          green:82/255.0f
                                           blue:164/255.0f alpha:1] forState:UIControlStateNormal];

所以,我的症状是:

- 大部分时间不会发生崩溃。

-即使代码相同,崩溃也只会发生在四个视图控制器之一上。

- 崩溃只在模拟器中被发现(与此有关吗??)这可能只是因为在模拟器中进行的测试比在设备上发生的要多得多。

-我的项目使用ARC。

的代码FancySegmentedControl如下:

@interface FancySegmentedControl : UISegmentedControl
{
    UIColor *bgNotSelected;
    UIColor *bgSelected;
    UIColor *barNotSelected;
    UIColor *barSelected;
}

-(void)setBackgroundColor:(UIColor *)color forState:(UIControlState)state;

-(void)setBarColor:(UIColor *)color forState:(UIControlState)state;

-(void)setTextAttributes:(NSDictionary *)attrs forState:(UIControlState) state;

@end

@implementation FancySegmentedControl

- (id)initWithItems:(NSArray *)items
{
    self = [super initWithItems:items];
    bgSelected = [UIColor blueColor];
    bgNotSelected = [UIColor whiteColor];
    barNotSelected = [UIColor lightGrayColor];
    barSelected = [UIColor orangeColor];
    self.selectedSegmentIndex = 0;
    if (self) {
        //change text stuff
        NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                    [UIFont boldSystemFontOfSize:17], UITextAttributeFont,
                                    [UIColor blackColor], UITextAttributeTextColor,
                                    nil];
        [self setTitleTextAttributes:attributes forState:UIControlStateNormal];
        NSDictionary *highlightedAttributes = [NSDictionary dictionaryWithObject:[UIColor whiteColor] forKey:UITextAttributeTextColor];
        [self setTitleTextAttributes:highlightedAttributes forState:UIControlStateHighlighted];

        //set all dividers to nothing
        UIView *yourView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 1, 30)];
        UIGraphicsBeginImageContext(yourView.bounds.size);
        [yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        [self setDividerImage:image
          forLeftSegmentState:UIControlStateNormal
            rightSegmentState:UIControlStateNormal
                   barMetrics:UIBarMetricsDefault];
        [self setDividerImage:image
          forLeftSegmentState:UIControlStateSelected
            rightSegmentState:UIControlStateNormal
                   barMetrics:UIBarMetricsDefault];
        [self setDividerImage:image
          forLeftSegmentState:UIControlStateNormal
            rightSegmentState:UIControlStateSelected
                   barMetrics:UIBarMetricsDefault];


        yourView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 30)];
        yourView.backgroundColor = bgNotSelected;
        UIView *barView = [[UIView alloc] initWithFrame:CGRectMake(0, yourView.frame.size.height - 3, 40, 3)];
        barView.backgroundColor = barNotSelected;
        [yourView addSubview:barView];
        UIGraphicsBeginImageContext(yourView.bounds.size);
        [yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
        image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        UIImage *normalBackgroundImage = image;
        [self setBackgroundImage:normalBackgroundImage
                        forState:UIControlStateNormal
                      barMetrics:UIBarMetricsDefault];

        yourView.backgroundColor = bgSelected;
        barView = [[UIView alloc] initWithFrame:CGRectMake(0, yourView.frame.size.height - 3, 40, 3)];
        barView.backgroundColor = barSelected;
        [yourView addSubview:barView];
        UIGraphicsBeginImageContext(yourView.bounds.size);
        [yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
        image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        UIImage *selectedBackgroundImage = image;
        [self setBackgroundImage:selectedBackgroundImage
                        forState:UIControlStateSelected
                      barMetrics:UIBarMetricsDefault];
    }
    return self;
}

-(void)setBackgroundColor:(UIColor *)color forState:(UIControlState)state
{
    UIColor *barColor;
    if (state == UIControlStateSelected)
    {
        bgSelected = color;
        barColor = barSelected;
    }
    else
    {
        bgNotSelected = color;
        barColor = barNotSelected;
    }
    UIView *yourView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 30)];
    yourView.backgroundColor = color;
    UIView *barView = [[UIView alloc] initWithFrame:CGRectMake(0, yourView.frame.size.height - 3, 40, 3)];
    barView.backgroundColor = barColor;
    [yourView addSubview:barView];
    UIGraphicsBeginImageContext(yourView.bounds.size);
    [yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    [self setBackgroundImage:image
                    forState:state
                  barMetrics:UIBarMetricsDefault];
}

-(void)setBarColor:(UIColor *)color forState:(UIControlState)state
{
    UIColor *bgColor;
    if (state == UIControlStateSelected)
    {
        barSelected = color;
        bgColor = bgSelected;
    }
    else
    {
        barNotSelected = color;
        bgColor = bgNotSelected;
    }
    UIView *yourView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 30)];
    yourView.backgroundColor = bgColor;
    UIView *barView = [[UIView alloc] initWithFrame:CGRectMake(0, yourView.frame.size.height - 3, 40, 3)];
    barView.backgroundColor = color;
    [yourView addSubview:barView];
    UIGraphicsBeginImageContext(yourView.bounds.size);
    [yourView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    [self setBackgroundImage:image
                    forState:state
                  barMetrics:UIBarMetricsDefault];
}

-(void)setTextAttributes:(NSDictionary *)attrs forState:(UIControlState) state
{
    if (state == UIControlStateSelected)
    {
        //in case user mistakes the states
        state = UIControlStateHighlighted;
    }
    [self setTitleTextAttributes:attrs forState:state];
}


/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}
*/

@end

完整的错误信息:

* thread #1: tid = 0x1f03, 0x0134609b libobjc.A.dylib`objc_msgSend + 15, stop reason =     EXC_BAD_ACCESS (code=2, address=0xb0000008)
frame #0: 0x0134609b libobjc.A.dylib`objc_msgSend + 15
frame #1: 0x0059bcd5 UIKit`-[UISegmentedControl _setBackgroundImage:forState:barMetrics:] + 148
frame #2: 0x0059bd69 UIKit`-[UISegmentedControl setBackgroundImage:forState:barMetrics:] + 73
frame #3: 0x0004f9f5 Services`-[FancySegmentedControl setBarColor:forState:](self=0x0ea5d740, _cmd=0x000518fd, color=0x08db4630, state=0x00000004) + 1141 at FancySegmentedControl.m:135
frame #4: 0x0000538c Services`-[ServicesViewController fixSearchBar](self=0x07f791a0, _cmd=0x0005170b) + 1132 at ServicesViewController.m:174
frame #5: 0x00003f38 Services`-[ServicesViewController viewDidLoad](self=0x07f791a0, _cmd=0x017fe1dd) + 616 at ServicesViewController.m:49
frame #6: 0x0056964e UIKit`-[UIViewController view] + 184
frame #7: 0x00569941 UIKit`-[UIViewController contentScrollView] + 36
frame #8: 0x0057b47d UIKit`-[UINavigationController _computeAndApplyScrollContentInsetDeltaForViewController:] + 36
frame #9: 0x0057b66f UIKit`-[UINavigationController _layoutViewController:] + 43
frame #10: 0x0057b93b UIKit`-[UINavigationController _startTransition:fromViewController:toViewController:] + 303
frame #11: 0x0057c3df UIKit`-[UINavigationController _startDeferredTransitionIfNeeded] + 288
frame #12: 0x0057c561 UIKit`-[UINavigationController __viewWillLayoutSubviews] + 33
frame #13: 0x006984ca UIKit`-[UILayoutContainerView layoutSubviews] + 222
frame #14: 0x004e2301 UIKit`-[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 145
frame #15: 0x019b8e72 CoreFoundation`-[NSObject performSelector:withObject:] + 66
frame #16: 0x003c292d QuartzCore`-[CALayer layoutSublayers] + 266
frame #17: 0x003cc827 QuartzCore`CA::Layer::layout_if_needed(CA::Transaction*) + 231
frame #18: 0x00352fa7 QuartzCore`CA::Context::commit_transaction(CA::Transaction*) + 377
frame #19: 0x00354ea6 QuartzCore`CA::Transaction::commit() + 374
frame #20: 0x00354580 QuartzCore`CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 80
frame #21: 0x0198b9ce CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
frame #22: 0x01922670 CoreFoundation`__CFRunLoopDoObservers + 384
frame #23: 0x018ee4f6 CoreFoundation`__CFRunLoopRun + 1174
frame #24: 0x018eddb4 CoreFoundation`CFRunLoopRunSpecific + 212
frame #25: 0x018edccb CoreFoundation`CFRunLoopRunInMode + 123
frame #26: 0x01b49879 GraphicsServices`GSEventRunModal + 207
frame #27: 0x01b4993e GraphicsServices`GSEventRun + 114
frame #28: 0x004a3a9b UIKit`UIApplicationMain + 1175
frame #29: 0x000036d0 Services`main(argc=1, argv=0xbffff214) + 80 at main.m:16
frame #30: 0x000025e5 Services`start + 53
4

2 回答 2

2

UIControlState 是一个枚举。您正在传递一个指向应该是 UIControlState 的值的指针,但实际上指针的值是直接使用的,甚至没有被取消引用。

从签名中的参数中删除指针UIControlState,您就可以了。

-(void)setBarColor:(UIColor *)color forState:(UIControlState)state

这将满足 UISegmentedControl 的方法签名:

-(void)setBackgroundImage:(UIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics
于 2013-08-30T22:08:16.463 回答
0

您是否尝试过在打开僵尸的情况下运行它?

EXC_BAD_ACCESS 主要是因为您试图对已经释放的内存做一些事情,而那里的东西现在是垃圾。

在您的代码中看起来像:

frame #1: 0x0059bcd5 UIKit`-[UISegmentedControl _setBackgroundImage:forState:barMetrics:] + 148

是我们在您出现此错误之前看到的最后一件事。

在这里放一个断点并检查参数是否真实等。或者

您有时只看到此崩溃的原因可能与内存使用有关。代码、模拟器、设备等中的其他内容导致内存被清理和重用。无论出于何种原因,大部分时间都不会调用释放分配器,因此即使根据程序的语义不一定必须如此,指向该内存块的指针仍然有效。在其他压力更大的情况下,可能是内存正在被回收,释放器正在运行,现在系统知道该内存已返回到系统的分配堆,因此当您尝试摆弄它时它会引发异常。

于 2013-08-30T21:45:35.957 回答