iOS崩溃日志打印出来或者写进文件

对于真机，日志没法保存，不好分析问题。所以有必要将日志保存到应用的Docunment目录下，方便取出分析。

首先是日志输出，分为c的printf和标准的NSLog输出，printf会向标准输出(sedout)打印，而NSLog则是向标准出错(stderr)，我们需要同时让他们都将日志打印到一个文件中。 其次是Crash问题；Crash分为两种，一种是由EXC_BAD_ACCESS引起的，原因是访问了不属于本进程的内存地址，有可能是访问已被释放的内存；另一种是未被捕获的Objective-C异常（NSException），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，我们是有办法将它记录下来的，如果日志记录得当，能够解决绝大部分崩溃的问题。

我写了两个函数用于写NSLog日志和Crash日志，这个两个函数都必须在AppDelegate文件中下面的函数里添加

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

//连接xcode时可以从监视器中看日志 没连接时Log日志会输出到文件中，

[self redirectNSLogToDocumentFolder];

- (void)redirectNSLogToDocumentFolder

{

//如果已经连接Xcode调试则不输出到文件

if(isatty(STDOUT_FILENO)) {

return;

}

UIDevice *device = [UIDevice currentDevice];

if([[device model] hasSuffix:@"Simulator"]){ //在模拟器不保存到文件中

return;

}

//将NSlog打印信息保存到Document目录下的Log文件夹下

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *logDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Log"];

NSFileManager *fileManager = [NSFileManager defaultManager];

BOOL fileExists = [fileManager fileExistsAtPath:logDirectory];

if (!fileExists) {

[fileManager createDirectoryAtPath:logDirectory withIntermediateDirectories:YES attributes:nil error:nil];

}

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

[formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"]];

[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; //每次启动后都保存一个新的日志文件中

NSString *dateStr = [formatter stringFromDate:[NSDate date]];

NSString *logFilePath = [logDirectory stringByAppendingFormat:@"/%@.log",dateStr];

// 将log输入到文件

freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stdout);

freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);

//未捕获的Objective-C异常日志

NSSetUncaughtExceptionHandler (&UncaughtExceptionHandler);

}

void UncaughtExceptionHandler(NSException* exception)

{

NSString* name = [ exception name ];

NSString* reason = [ exception reason ];

NSArray* symbols = [ exception callStackSymbols ]; // 异常发生时的调用栈

NSMutableString* strSymbols = [ [ 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: @"\r\n" ];

}

//将crash日志保存到Document目录下的Log文件夹下

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *logDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Log"];

NSFileManager *fileManager = [NSFileManager defaultManager];

BOOL fileExists = [fileManager fileExistsAtPath:logDirectory];

if (!fileExists) {

[fileManager createDirectoryAtPath:logDirectory withIntermediateDirectories:YES attributes:nil error:nil];

}

NSString *logFilePath = [logDirectory stringByAppendingPathComponent:@"UncaughtException.log"];

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

[formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"]];

[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

NSString *dateStr = [formatter stringFromDate:[NSDate date]];

NSString *crashString = [NSString stringWithFormat:@"<- %@ ->[ Uncaught Exception ]\r\nName: %@, Reason: %@\r\n[ Fe Symbols Start ]\r\n%@[ Fe Symbols End ]", dateStr, name, reason, strSymbols];

//把错误日志写到文件中

freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", (__bridge FILE *)(crashString));

//把错误日志发送到邮箱

// NSString *urlStr = [NSString stringWithFormat:@"mailto://test@163.com?subject=bug报告&body=感谢您的配合!<br><br><br>错误详情:<br>%@",crashString ];

// NSURL *url = [NSURL URLWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

// [[UIApplication sharedApplication] openURL:url];

}