得到系统磁盘大小和可用磁盘大小

 -(NSNumber *)systemSize:(NSString *)folderPath
{
return [[[NSFileManager defaultManager] attributesOfFileSystemForPath:folderPath error:NULL] objectForKey:NSFileSystemSize];
}


-(NSNumber *)systemFreeSize:(NSString *)folderPath
{
return [[[NSFileManager defaultManager] attributesOfFileSystemForPath:folderPath error:NULL] objectForKey:NSFileSystemFreeSize];
}