EXC_BAD_ACCESS與ARC

-2

我正在使用ARC，我有一個CustomTableViewController，並且將CustomView添加到我的背景單元格，頁眉和頁腳。EXC_BAD_ACCESS與ARC

例如在tableView:viewForFooterInSection方法我把這些代碼行：

- (UIView *) tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section 
{ 
    CustomFooter *footer = [[CustomFooter alloc] init]; 
    return footer; 
}

CustomFooter是的UIView的子類，繪製一個矩形作爲背景細胞與- (void)drawRect:(CGRect)rect

當我運行在應用程序模擬器的作品，但它試圖在我的iPhone上時崩潰。

我該如何解決？

這是我的崩潰報告：

Date/Time:  2012-06-28 12:37:07.168 +0200 
OS Version:  iPhone OS 5.1.1 (9B206) 
Report Version: 104 

Exception Type: EXC_BAD_ACCESS (SIGSEGV) 
Exception Codes: KERN_INVALID_ADDRESS at 0x00000009 
Crashed Thread: 0 

Thread 0 name: Dispatch queue: com.apple.main-thread 
Thread 0 Crashed: 
0 libobjc.A.dylib     0x3508cf78 objc_msgSend + 16 
1 CoreFoundation     0x372d5e90 CFRetain + 76 
2 CoreFoundation     0x372dfb74 +[__NSArrayI __new::] + 48 
3 CoreFoundation     0x372dfa8e -[__NSPlaceholderArray initWithObjects:count:] + 294 
4 CoreFoundation     0x3730ce68 +[NSArray arrayWithObjects:] + 460 
5 CustomTable      0x0004766e drawLinearGradient (Common.m:15) 
6 CustomTable      0x00048c14 -[CustomFooter drawRect:] (CustomFooter.m:50) 
7 UIKit       0x3107015e -[UIView(CALayerDelegate) drawLayer:inContext:] + 270 
8 QuartzCore      0x374b74de -[CALayer drawInContext:] + 110 
9 QuartzCore      0x374b6b38 CABackingStoreUpdate_ + 1776 
10 QuartzCore      0x374b632e CA::Layer::display_() + 950 
11 QuartzCore      0x374b5f5a CA::Layer::display() + 122 
12 QuartzCore      0x374b5e9c CA::Layer::display_if_needed(CA::Transaction*) + 168 
13 QuartzCore      0x374b5844 CA::Context::commit_transaction(CA::Transaction*) + 228 
14 QuartzCore      0x374b5578 CA::Transaction::commit() + 308 
15 QuartzCore      0x374dd90a CA::Transaction::flush() + 38 
16 QuartzCore      0x374dd8dc +[CATransaction flush] + 28 
17 UIKit       0x310a6108 -[UIApplication _reportAppLaunchFinished] + 36 
18 UIKit       0x31093b2c -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 1256 
19 UIKit       0x31061abc -[UIApplication handleEvent:withNewEvent:] + 1004 
20 UIKit       0x31061560 -[UIApplication sendEvent:] + 48 
21 UIKit       0x31060f34 _UIApplicationHandleEvent + 5820 
22 GraphicsServices    0x33aa3224 PurpleEventCallback + 876 
23 CoreFoundation     0x3736151c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 32 
24 CoreFoundation     0x373614be __CFRunLoopDoSource1 + 134 
25 CoreFoundation     0x3736030c __CFRunLoopRun + 1364 
26 CoreFoundation     0x372e349e CFRunLoopRunSpecific + 294 
27 CoreFoundation     0x372e3366 CFRunLoopRunInMode + 98 
28 UIKit       0x31092864 -[UIApplication _run] + 544 
29 UIKit       0x3108fcce UIApplicationMain + 1074 
30 CustomTable      0x00046798 main (main.m:16) 
31 CustomTable      0x0004673c start + 32 

Thread 1 name: Dispatch queue: com.apple.libdispatch-manager 
Thread 1: 
0 libsystem_kernel.dylib   0x315343a8 kevent + 24 
1 libdispatch.dylib    0x304b9ea4 _dispatch_mgr_invoke + 708 
2 libdispatch.dylib    0x304b9bc2 _dispatch_mgr_thread + 30 

Thread 2: 
0 libsystem_kernel.dylib   0x31544cd4 __workq_kernreturn + 8 
1 libsystem_c.dylib    0x33bfcf36 _pthread_wqthread + 610 
2 libsystem_c.dylib    0x33bfccc8 start_wqthread + 0 

Thread 3: 
0 libsystem_kernel.dylib   0x31544cd4 __workq_kernreturn + 8 
1 libsystem_c.dylib    0x33bfcf36 _pthread_wqthread + 610 
2 libsystem_c.dylib    0x33bfccc8 start_wqthread + 0 

Thread 4 name: WebThread 
Thread 4: 
0 libsystem_kernel.dylib   0x31534004 mach_msg_trap + 20 
1 libsystem_kernel.dylib   0x315341fa mach_msg + 50 
2 CoreFoundation     0x373613ec __CFRunLoopServiceMachPort + 120 
3 CoreFoundation     0x37360124 __CFRunLoopRun + 876 
4 CoreFoundation     0x372e349e CFRunLoopRunSpecific + 294 
5 CoreFoundation     0x372e3366 CFRunLoopRunInMode + 98 
6 WebCore       0x32c8cc9c _ZL12RunWebThreadPv + 396 
7 libsystem_c.dylib    0x33c0272e _pthread_start + 314 
8 libsystem_c.dylib    0x33c025e8 thread_start + 0 

Thread 0 crashed with ARM Thread State: 
r0: 0x00125860 r1: 0x30d16b7c  r2: 0x3f9a3570  r3: 0x0014b170 
r4: 0x00000001 r5: 0x2fe41188  r6: 0x0014b178  r7: 0x2fe4114c 
r8: 0x0014b170 r9: 0x0c345adf  r10: 0x00000002  r11: 0x00000001 
ip: 0x3f97f814 sp: 0x2fe41140  lr: 0x372d5e97  pc: 0x3508cf78 
cpsr: 0x00000030

這是我的drawRect功能分爲CustomFooter：

- (void)drawRect:(CGRect)rect 
{ 

CGContextRef context = UIGraphicsGetCurrentContext(); 

CGColorRef whiteColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0].CGColor; 
CGColorRef lightGrayColor = [UIColor colorWithRed:230.0/255.0 green:230.0/255.0 blue:230.0/255.0 alpha:1.0].CGColor; 
CGColorRef darkGrayColor = [UIColor colorWithRed:187.0/255.0 green:187.0/255.0 blue:187.0/255.0 alpha:1.0].CGColor; 
CGColorRef shadowColor = [UIColor colorWithRed:0.2 green:0.2 blue:0.2 alpha:0.5].CGColor; 

CGFloat paperMargin = 9.0; 
CGRect paperRect = CGRectMake(self.bounds.origin.x+paperMargin, 
           self.bounds.origin.y, 
           self.bounds.size.width-paperMargin*2, 
           self.bounds.size.height); 

CGRect arcRect = paperRect; 
arcRect.size.height = 8; 

CGContextSaveGState(context); 
CGMutablePathRef arcPath = createArcPathFromBottomOfRect(arcRect, 4.0); 
CGContextAddPath(context, arcPath); 
CGContextClip(context);    
drawLinearGradient(context, paperRect, lightGrayColor, darkGrayColor); 
CGContextRestoreGState(context); 

CGContextSaveGState(context); 
CGPoint pointA = CGPointMake(arcRect.origin.x, 
          arcRect.origin.y + arcRect.size.height - 1); 
CGPoint pointB = CGPointMake(arcRect.origin.x, arcRect.origin.y); 
CGPoint pointC = CGPointMake(arcRect.origin.x + arcRect.size.width - 1, 
          arcRect.origin.y); 
CGPoint pointD = CGPointMake(arcRect.origin.x + arcRect.size.width - 1, 
          arcRect.origin.y + arcRect.size.height - 1); 
draw1PxStroke(context, pointA, pointB, whiteColor); 
draw1PxStroke(context, pointC, pointD, whiteColor);  
CGContextRestoreGState(context); 

CGContextAddRect(context, paperRect); 
CGContextAddPath(context, arcPath); 
CGContextEOClip(context); 
CGContextAddPath(context, arcPath); 
CGContextSetShadowWithColor(context, CGSizeMake(0, 2), 3.0, shadowColor); 
CGContextFillPath(context); 

CFRelease(arcPath); 
}

drawLinearGradient

void drawLinearGradient(CGContextRef context, CGRect rect, CGColorRef startColor, CGColorRef endColor) 
{ 
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
CGFloat locations[] = { 0.0, 1.0 }; 
NSArray *colors = [NSArray arrayWithObjects:(__bridge id)startColor, (__bridge id)endColor, nil]; 
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef) colors, locations); 

CGPoint startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect)); 
CGPoint endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect)); 

CGContextSaveGState(context); 
CGContextAddRect(context, rect); 
CGContextClip(context); 
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0); 
CGContextRestoreGState(context); 

CGGradientRelease(gradient); 
CGColorSpaceRelease(colorSpace); 

}

來源

2012-06-28 andreapavan

我們展示崩潰日誌/堆棧跟蹤。 – Till

對不起，我現在發佈 – andreapavan

這個問題似乎出現在你的'drawRect'方法中。請發佈該方法的代碼。 –

JeremyP對陣列初始化器崩潰的分析是正確的。我猜的根本原因是：

CGColorRef whiteColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0].CGColor;

我的猜測是因爲你不使用你UIColor創造超越這一說法，將熱切ARC釋放。這也意味着你沒有以任何方式保留的CGColor（以及哪些ARC不會保留給你）可能也會被釋放和處理。

嘗試用這樣的事情每個UIColors（和白茫茫的一片，只使用[UIColor whiteColor]）的工作圍繞它：

UIColor *color = [UIColor ...]; 
CGColorRef cgColor = CFRetain(color.CGColor); 
color = nil;

來源

2012-06-28 13:23:07 Jesper

解決！這正是顏色傳遞給drawLineGradient方法的過程。我通過傳遞一個UIColor方法解決了這個問題，並轉換爲CGColor。 'NSArray * colors = [NSArray arrayWithObjects：（id）[startColor CGColor]，（id）[endColor CGColor]，nil];' – andreapavan

更簡單的解決方法是存儲並傳遞UIColor，然後使用myColor.CGColor需要的時候。 – kritzikratzi

有沒有足夠的背景這裏來診斷問題與任何確定性，但我目前的猜測是你的功能drawLinearRect() crea使用arrayWithObjects:測試NSArray，並且參數列表中的一個對象是垃圾。確保列表沒有終止，並且其中的所有對象都是合理的。

來源

2012-06-28 12:22:50 JeremyP

是的，你是對的！問題出在包含漸變顏色的數組中。但是這怎麼發生？我發佈'drawLineGradient' – andreapavan

EXC_BAD_ACCESS與ARC

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