给label text 上色 && 给textfiled placeholder 上色

1、给label text 上色：

NSInteger stringLength = ;
        stringLength = model.ToUserNickName.length;
        NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:string];
        NSLog(@"textLength is %u", model.ToUserNickName.length);
        [str addAttribute:NSForegroundColorAttributeName value:[UIColor grayColor] range:NSMakeRange(,stringLength)];
        self.CommentContent.attributedText = str;     // self.CommentContent.attributedText  是一个 label

2、

textField.placeholder = @"username is in here!";
[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
[textField setValue:[UIFont boldSystemFontOfSize:] forKeyPath:@"_placeholderLabel.font"]; 

// 转自 http://blog.csdn.net/woaifen3344/article/details/38352015