- (void)testAlert {
 UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleAlert];
 [alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil]];
 NSDictionary *titleAttr = @{
  NSFontAttributeName:[UIFont boldSystemFontOfSize:20],
  NSForegroundColorAttributeName:[UIColor greenColor]
  };
 NSAttributedString *attributedTitle = [[NSAttributedString alloc] initWithString:@"测试有颜色标题" attributes:titleAttr];
 [alert setValue:attributedTitle forKey:@"attributedTitle"];

 NSDictionary *messageAttr = @{
  NSFontAttributeName:[UIFont systemFontOfSize:12],
  NSForegroundColorAttributeName:[UIColor redColor]
  };
 NSAttributedString *attributedMessage = [[NSAttributedString alloc] initWithString:@"测试有颜色文本" attributes:messageAttr];
 [alert setValue:attributedMessage forKey:@"attributedMessage"];
 [self presentViewController:alert animated:YES completion:nil];
}