具有多种颜色的UIAlertController消息

Question

我想将第二句改为另一种颜色。

UIAlertController * alert=[UIAlertController
    alertControllerWithTitle:@"Warning!!!" message:@"This is the first sentence.\r\n\n
This is the second sentence I want a different color.\r\n\n
This is the third sentence.)"
preferredStyle:UIAlertControllerStyleAlert];