iOS – NSLog、UncaughtException日志保存到文件

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];
if (![fileManager fileExistsAtPath:logDirectory]) {
[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 ]\r\n\r\n”, dateStr, name, reason, strSymbols];
//把错误日志写到文件中
if (![fileManager fileExistsAtPath:logFilePath]) {
[crashString writeToFile:logFilePath atomically:YES encoding:NSUTF8StringEncoding error:nil];
}else{
NSFileHandle *outFile = [NSFileHandle fileHandleForWritingAtPath:logFilePath];
[outFile seekToEndOfFile];
[outFile writeData:[crashString dataUsingEncoding:NSUTF8StringEncoding]];
[outFile closeFile];
}

//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];
}

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