我正在使用ARC，我有一个CustomTableViewController，我正在为我的背景单元格，页眉和页脚添加一个CustomView。
例如在tableView:viewForFooterInSection方法中，我放了以下这些代码：
- (UIView *) tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section
{
CustomFooter *footer = [[CustomFooter alloc] init];
return footer;
}
CustomFooter是UIView的子类，它使用- (void)drawRect:(CGRect)rect
当我在模拟器上运行应用程序时，但是当我尝试使用iPhone时它会崩溃。
我该如何解决？
这是我的崩溃报告：
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
这是我在CustomFooter中的drawRect函数：
- (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);
}
答案 0 :(得分：0)
此处没有足够的上下文可以确定地诊断问题，但我目前的猜测是，您的函数drawLinearRect()使用NSArray和参数中的一个对象创建arrayWithObjects:列表是垃圾。确保列表终止为零并且其中的所有对象都是合理的。
答案 1 :(得分：0)
JeremyP对数组初始化程序崩溃的分析是正确的。我猜测的根本原因是：
CGColorRef whiteColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0].CGColor;
我的猜测是，由于你没有使用你在此声明之外创建的UIColor，因此ARC会热切地发布它。这也意味着你没有以任何方式保留的CGColor（以及ARC不会为你保留的那些）可能也被释放和解除分配。
尝试为每个UIColors使用类似的东西（对于白色的，只需使用[UIColor whiteColor]）：
UIColor *color = [UIColor ...];
CGColorRef cgColor = CFRetain(color.CGColor);
color = nil;