打印日志

在真机，或真机没连接到电脑时，可以把日志信息输出到文件

1.设置日志文件路径

- (NSString*)logFilePath {
//非越狱版路径
 #ifndef CRACK
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
     NSString *documentsDirectory = [paths objectAtIndex:0];
//越狱版路径
 #else
     NSString *documentsDirectory = @"/var/root/Media/xiaodao/";
 #endif
     NSString *logDir = [documentsDirectory stringByAppendingPathComponent:@"logs"];
     BOOL isDir = YES;
     //如果logs文件夹存不存在，则创建
     if([[NSFileManager defaultManager] fileExistsAtPath:logDir isDirectory:&isDir] == NO)
     {
         [[NSFileManager defaultManager] createDirectoryAtPath:logDir withIntermediateDirectories:YES attributes:nil error:nil];
     }
     //以当天的时间为文件名，文件名后缀为.log
     NSString *fileName =[NSString stringWithFormat:@"%@.log",[NSDate date]];
     NSString *logPath = [logDir stringByAppendingPathComponent:fileName];
     return logPath;
 }

2.开始打印日志

1 - (void)startLog {
2    freopen([[self logFilePath] cStringUsingEncoding:NSASCIIStringEncoding],"a+",stderr);
3 }

freopen重定向打印

stderr为标准出错信息

3.关闭打印日志

1 - (void)finishLog { 
2     fflush(stderr);
3     dup2(dup(STDERR_FILENO), STDERR_FILENO);
4     close(dup(STDERR_FILENO));
5 }

4.清空日志文件

1 - (BOOL)deleteLogFile {
2     BOOL success = [[NSFileManager defaultManager] removeItemAtPath:[self logFilePath] error:nil];
3     return success;
4 }