问题
NSURL printing null. What's the reason?
NSString *webStr = [[NSString alloc] initWithFormat:@"%@",[webArray objectAtIndex:1]];
NSLog(@"urlString = %@",webStr); // its printing correct url string
NSURL *webURL = [[NSURL alloc] initWithString:webStr];
NSLog(@"url = %@",webURL); // its printing null
[webURL release];
[webStr release];
回答1:
You should do the following.
NSString *webStr = [[NSString alloc] initWithFormat:@"%@",[webArray objectAtIndex:1]];
NSLog(@"urlString = %@",webStr); // its printing correct url string
NSURL *webURL = [[NSURL alloc] initWithString:[webStr stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]];
NSLog(@"url = %@",webURL); // it should print it
[webURL release];
[webStr release];
I have used NSASCIIStringEncoding but you can use UTF8 too or any other encoding.
回答2:
from the docs for -[NSURL initWithString:]:
If the string was malformed, returns nil.
This method expects URLString to contain any necessary percent escape codes, which are ‘:’, ‘/’, ‘%’, ‘#’, ‘;’, and ‘@’. Note that ‘%’ escapes are translated via UTF-8.
which raises: what's your input?
回答3:
NSLog(@"urlString = %@",webStr); // its printing correct url string
It's not printing the correct URL string. It's just printing the string. So if NSURL *webURL = [[NSURL alloc] initWithString:webStr] returns nil it means that your string is not valid URL.
来源：https://stackoverflow.com/questions/4905843/created-nsurl-is-null