如何将NSLog的数据和崩溃信息保存到本地文件中

照例先上github地址

做这个的原因
程序测试时并不是总是连着Xcode的，这就导致如果测试过程中程序出现崩溃时，可能是由于数据异常引起的，而我们有无法看到数据，连接Xcode重测时，有时候问题并不能重现，导致很多问题无法确认，所以想把所有NSLog输出的数据，保存到文件中。这样，当程序出问题时，我们只需导出log文件，查看，便可很容易的复现问题。

用法

• 如果想要NSLog输出的内容和崩溃信息都放入日志文件中，就在application:didFinishLaunchingWithOptions:方法中实现方法redirectNSLogToDocumentFolder
• 如果只是想要保存崩溃信息到日志文件中，只需在application:didFinishLaunchingWithOptions:方法中实现NSSetUncaughtExceptionHandler(&UncaughtExceptionHandler);就可以了。

保持淡定， 人生从此不再寂寞。(其实，这只是个分割线，哈哈)

文笔不好，还是直接上代码

- (void)redirectNSLogToDocumentFolder
{
//如果已经连接Xcode调试则不输出到文件
if (isatty(STDOUT_FILENO)) {
    return;
}

//判定如果是模拟器就不输出
UIDevice *device = [UIDevice currentDevice];
if ([[device model]hasSuffix:@"Simulator"]) {
    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) {
    NSError *error = nil;
    [fileManager createDirectoryAtPath:logDirectory withIntermediateDirectories:YES attributes:nil error:&error];
    if (error) {
        NSLog(@"error = %@",[error localizedDescription]);
    }
}

NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setLocale:[[NSLocale alloc]initWithLocaleIdentifier:@"zh_CN"]];
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
//每次启动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文件输出到文件
freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a++", stdout);
freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a++", stderr);
//捕获Object-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];
//将调用栈平成输出日志的字符串
for (NSString *str in symbols) {
    [strSymbols appendString:str];
    [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]) {
    NSError *error = nil;
    [fileManager createDirectoryAtPath:logDirectory withIntermediateDirectories:YES attributes:nil error:&error];
    if (error) {
        NSLog(@"error = %@",[error localizedDescription]);
    }
}

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://(此处为邮箱地址)?subject=bug&body=感谢您的配合错误详情:%@",crashString];
NSURL *url = [NSURL URLWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
[[UIApplication sharedApplication]openURL:url];
}

注:这段代码写的挺早了，参考链接已找不到，不能贴出来，但仍要感谢。