作者：缺氧 | 来源：互联网 | 2023-08-04 16:37
原文地址&＃xff1a;http://www.cnblogs.com/alario/
如果你去4S店修车&＃xff0c;给小工说你的车哪天怎么样怎么样了&＃xff0c;小工有可能会立即搬出一台电脑&＃xff0c;插上行车电脑把日志打出来&＃xff0c;然后告诉你你的车发生过什么故障。汽车尚且如此&＃xff0c;何况移动互联网应用呢。
本文第一篇&＃xff1a;经营你的iOS应用日志&＃xff08;一&＃xff09;&＃xff1a;开始编写日志组件
言归正传。开发iOS应用&＃xff0c;解决Crash问题始终是一个难题。Crash分为两种&＃xff0c;一种是由EXC_BAD_ACCESS引起的&＃xff0c;原因是访问了不属于本进程的内存地址&＃xff0c;有可能是访问已被释放的内存&＃xff1b;另一种是未被捕获的Objective-C异常&＃xff08;NSException&＃xff09;&＃xff0c;导致程序向自身发送了SIGABRT信号而崩溃。其实对于未捕获的Objective-C异常&＃xff0c;我们是有办法将它记录下来的&＃xff0c;如果日志记录得当&＃xff0c;能够解决绝大部分崩溃的问题。这里对于UI线程与后台线程分别说明。
先看UI线程。iOS SDK提供了NSSetUncaughtExceptionHandler函数&＃xff0c;用法如&＃xff1a;
NSSetUncaughtExceptionHandler( handleRootException );
这样在UI线程发生未捕获异常后&＃xff0c;进程崩溃之前&＃xff0c;handleRootException会被执行。这个函数实现如下
static void handleRootException( NSException* exception )
{NSString* name &＃61; [ exception name ];NSString* reason &＃61; [ exception reason ];NSArray* symbols &＃61; [ exception callStackSymbols ]; // 异常发生时的调用栈
NSMutableString* strSymbols &＃61; [ [ NSMutableString alloc ] init ]; // 将调用栈拼成输出日志的字符串
for ( NSString* item in symbols ){[ strSymbols appendString: item ];[ strSymbols appendString: &＃64;"\r\n" ];}// 写日志&＃xff0c;级别为ERROR
writeCinLog( __FUNCTION__, CinLogLevelError, &＃64;"[ Uncaught Exception ]\r\nName: %&＃64;, Reason: %&＃64;\r\n[ Fe Symbols Start ]\r\n%&＃64;[ Fe Symbols End ]", name, reason, strSymbols );[ strSymbols release ];// 这儿必须Hold住当前线程&＃xff0c;等待日志线程将日志成功输出&＃xff0c;当前线程再继续运行
blockingFlushLogs( __FUNCTION__ );// 写一个文件&＃xff0c;记录此时此刻发生了异常。这个挺有用的哦
NSDictionary* dict &＃61; [ NSDictionary dictionaryWithObjectsAndKeys:currentCinLogFileName(), &＃64;"LogFile", // 当前日志文件名称
currentCinLogFileFullPath(), &＃64;"LogFileFullPath", // 当前日志文件全路径
[ NSDate date ], &＃64;"TimeStamp", // 异常发生的时刻
nil ];NSString* path &＃61; [ NSString stringWithFormat: &＃64;"%&＃64;/Documents/", NSHomeDirectory() ];NSString* lastExceptionLog &＃61; [ NSString stringWithFormat: &＃64;"%&＃64;LastExceptionLog.txt", path ];[ dict writeToFile: lastExceptionLog atomically: YES ];}
而我们的日志组件必须实现blockingFlushLogs函数&＃xff0c;确保进程在日志完全写入文件后再退出。这个实现应该很简单吧。
当应用下次启动时&＃xff0c;我们可以检查&＃xff0c;如果有LastExceptionLog.txt&＃xff0c;则弹窗引导测试人员将日志发过来。如果iPhone上面配置了EMail帐户&＃xff0c;可以很简单的调用MFMailComposeViewController将日志文件作为附件发送&＃xff0c;当然也可以想其它办法。
记得正式发布的版本要将它条件编译去掉哦。
其中文件中的最后一条ERROR即为导致崩溃的异常&＃xff0c;而从ERROR之前的日志可以看出当前程序的运行情况。ERROR如下&＃xff1a;
<- 03-20 17:21:43 ERROR -> [UI] -[CinUIRunLoopActionManager(Protected) handleRootException:]
[ Uncaught Exception ]
Name: NSDestinationInvalidException, Reason: *** -[CinThreadRunLoopActionManager performSelector:onThread:withObject:waitUntilDone:modes:]: target thread exited while waiting for the perform
[ Fe Symbols Start ]
0 CoreFoundation 0x340c88d7 __exceptionPreprocess &＃43; 186
1 libobjc.A.dylib 0x343181e5 objc_exception_throw &＃43; 32
2 CoreFoundation 0x340c87b9 &＃43;[NSException raise:format:] &＃43; 0
3 CoreFoundation 0x340c87db &＃43;[NSException raise:format:] &＃43; 34
4 Foundation 0x35a12493 -[NSObject(NSThreadPerformAdditions) performSelector:onThread:withObject:waitUntilDone:modes:] &＃43; 998
5 Foundation 0x35a3afb5 -[NSObject(NSThreadPerformAdditions) performSelector:onThread:withObject:waitUntilDone:] &＃43; 108
6 MyiOSapplication 0x0022b7e9 -[CinThreadRunLoopActionManager(Protected) performAction:] &＃43; 144
13 UIKit 0x374b36b5 -[UIViewController _setViewAppearState:isAnimating:] &＃43; 144
14 UIKit 0x374b38c1 -[UINavigationController viewWillAppear:] &＃43; 288
15 UIKit 0x374b36b5 -[UIViewController _setViewAppearState:isAnimating:] &＃43; 144
16 UIKit 0x3750e61b -[UIViewController beginAppearanceTransition:animated:] &＃43; 190
17 UIKit 0x3750b415 -[UITabBarController transitionFromViewController:toViewController:transition:shouldSetSelected:] &＃43; 184
18 UIKit 0x3750b357 -[UITabBarController transitionFromViewController:toViewController:] &＃43; 30
19 UIKit 0x3750ac91 -[UITabBarController _setSelectedViewController:] &＃43; 300
20 UIKit 0x3750a9c5 -[UITabBarController setSelectedIndex:] &＃43; 240
21 MyiOSapplication 0x0007ef1d &＃43;[Utility ResetCurrentTabIndex] &＃43; 172
22 MyiOSapplication 0x001a87bd -[UIViewController(statusBar) dismissModalViewControllerAnimatedEx:] &＃43; 416
23 MyiOSapplication 0x001793fb -[ImageProcessingViewController save:] &＃43; 690
24 CoreFoundation 0x34022435 -[NSObject performSelector:withObject:withObject:] &＃43; 52
25 UIKit 0x3748c9eb -[UIApplication sendAction:to:from:forEvent:] &＃43; 62
26 UIKit 0x3748c9a7 -[UIApplication sendAction:toTarget:fromSender:forEvent:] &＃43; 30
27 UIKit 0x3748c985 -[UIControl sendAction:to:forEvent:] &＃43; 44
28 UIKit 0x3748c6f5 -[UIControl(Internal) _sendActionsForEvents:withEvent:] &＃43; 492
29 UIKit 0x3748d02d -[UIControl touchesEnded:withEvent:] &＃43; 476
30 UIKit 0x3748b50f -[UIWindow _sendTouchesForEvent:] &＃43; 318
31 UIKit 0x3748af01 -[UIWindow sendEvent:] &＃43; 380
32 UIKit 0x374714ed -[UIApplication sendEvent:] &＃43; 356
33 UIKit 0x37470d2d _UIApplicationHandleEvent &＃43; 5808
34 GraphicsServices 0x308a3df3 PurpleEventCallback &＃43; 882
35 CoreFoundation 0x3409c553 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ &＃43; 38
36 CoreFoundation 0x3409c4f5 __CFRunLoopDoSource1 &＃43; 140
37 CoreFoundation 0x3409b343 __CFRunLoopRun &＃43; 1370
38 CoreFoundation 0x3401e4dd CFRunLoopRunSpecific &＃43; 300
39 CoreFoundation 0x3401e3a5 CFRunLoopRunInMode &＃43; 104
40 GraphicsServices 0x308a2fcd GSEventRunModal &＃43; 156
41 UIKit 0x3749f743 UIApplicationMain &＃43; 1090
42 MyiOSapplication 0x000d4ccb main &＃43; 174
43 MyiOSapplication 0x000039c8 start &＃43; 40
[ Fe Symbols End ]
可以看到&＃xff0c;即使我们没有编译时生成的符号文件&＃xff0c;也能够打印出调用栈上的每个函数的名称&＃xff0c;只是没有文件名和行号。
那么&＃xff0c;除了UI线程之外&＃xff0c;自己创建的后台线程呢&＃xff1f;运行NSRunLoop的后台线程的线程函数应该如下&＃xff1a;
- ( void ) threadProc: ( NSString* )threadName
{NSThread* current &＃61; [ NSThread currentThread ];[ current setName: threadName ];NSAutoreleasePool *pool &＃61; [ [ NSAutoreleasePool alloc ] init ];// 一个没有实际作用的NSTimer&＃xff0c;确保NSRunLoop不退出。不知道有没有更好的办法啊
_dummyTimer &＃61; [ [ NSTimer timerWithTimeInterval: 10.0target: selfselector: &＃64;selector( dummyTimerProc: )userInfo: nilrepeats: YES ] retain ];NSRunLoop *r &＃61; [ NSRunLoop currentRunLoop ];[ r addTimer: _dummyTimer forMode: NSDefaultRunLoopMode ];&＃64;try {// 启动后台线程的NSRunLoop
[ r run ];}&＃64;catch ( NSException *exception ) {[ self handleRootException: exception ];// 一旦在线程根上捕捉到未知异常&＃xff0c;记录异常后本线程退出
}&＃64;finally {[ _dummyTimer invalidate ];[ _dummyTimer release ];[ pool release ];}
}
后台线程的handleRootException与UI线程基本一致。不过为了测试人员更加方便&＃xff0c;其实只要不是UI线程发生未捕获异常&＃xff0c;都可以先引导用户发送日志&＃xff0c;再把进程崩溃掉。
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