给UITextView增加了链接
现在在iOS添加你自己的Twitter账户更加简单了，现在你可以给一个NSAttributedString增加链接了，然后当它被点击的时候唤起一个定制的action。
首先，创建一个NSAttributedString然后增加给它增加一个NSLinkAttributeName 属性，见以下：
- NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"This is an example by @marcelofabri_"];
- [attributedString addAttribute:NSLinkAttributeName
- value:@"username://marcelofabri_"
- range:[[attributedString string] rangeOfString:@"@marcelofabri_"]];
- NSDictionary *linkAttributes = @{NSForegroundColorAttributeName: [UIColor greenColor],
- NSUnderlineColorAttributeName: [UIColor lightGrayColor],
- NSUnderlineStyleAttributeName: @(NSUnderlinePatternSolid)};
- // assume that textView is a UITextView previously created (either by code or Interface Builder)
- textView.linkTextAttributes = linkAttributes; // customizes the appearance of links
- textView.attributedText = attributedString;
- textView.delegate = self;
这样就可以让链接在文本中显示。然而，你也可以控制当链接被点击的时候会发生什么，实现这个可以使用UITextViewDelegate协议的新的shouldInteractWithURL方法，就像这样：
- - (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange {
- if ([[URL scheme] isEqualToString:@"username"]) {
- NSString *username = [URL host];
- // do something with this username
- // ...
- return NO;
- }
- return YES; // let the system open this URL
- }