I tried constructing the following NSURL for a custom URL scheme:
NSURL *url = [NSURL URLWithString:@"tweetie:///post?message=안녕 모두"];
[[UIApplication sharedApplication] openURL:url];
but it doesn’t perform correctly. How would you construct such a URL with non-English elements?
Apparently you may only send US-ASCII characters in URI strings. Try adding percent escapes to your string before sending it:
See String Conversion in Objective-C