Simple UIAlertView with NSAttributedString(s)

问题

I am looking for a simple way to use NSAttributedString with a very simple message box similar to:

NSString *new_item = [NSString stringWithFormat:@"<span style=\"font-family: Helvetica Neue; font-size: 12.0\">%@</span>", @"MOTD HTML String downloaded from website"];
NSAttributedString * attrStr = [[NSAttributedString alloc] initWithData:[new_item dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"MOTD"
                                                   message:attrStr
                                                  delegate:nil
                                         cancelButtonTitle:@"OK"
                                         otherButtonTitles:nil];
[alert show];

My above code takes a HTML formatted string that has been downloaded from a server, makes sure the text size will fit the screen properly, then tries to send the NSAttributedString to the UIAlertView. But UIAlertView does not like this. what would be the simplest way around this problem?(Non HTML formatted MOTD is not an option)

回答1:

Add your attributed string to label and add it as assessoryView to alert

UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Test Attributed String" message:@"" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:nil, nil];
UILabel *lbl = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc]initWithString:@"Hello red"];
[attributedStr addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
lbl.attributedText = attributedStr;
lbl.textAlignment = NSTextAlignmentCenter;
[alert setValue:lbl forKey:@"accessoryView"];
[alert show];

Now a days UIAlertView is deprecated. You can use UIAlertController.

回答2:

I got an idea from the @AshishKakkad answer only (+1). However, its UI isn't properly visible. So I'm showing you a way to format your message with attributedString.

Here's how I'm doing it:

NSMutableString *message = [NSMutableString string];
NSString *title = @"Message Heading";
[message appendString:title];
[message appendString:@"\n\n• Topic 1"];
[message appendString:@"\n• Topic 2"];
[message appendString:@"\n• Topic 3\n"]; //Important, I have added '\n' at last to have some extra space at bottom.

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Title" message:@"" delegate:self cancelButtonTitle:@"CancelButton" otherButtonTitles:@"OtherButton", nil];
//need to set a label as `accessoryView` of an alert.
[alert setValue:[self getLabelWithMessage:message withTitle:title] forKey:@"accessoryView"];
[alert show];

- (UILabel *)getLabelWithMessage:(NSMutableString *)message withTitle:(NSString *)title {
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setAlignment:NSTextAlignmentLeft];
    paragraphStyle.paragraphSpacing = 2.0f;
    paragraphStyle.headIndent = 20.0;
    paragraphStyle.firstLineHeadIndent = 20.0;
    paragraphStyle.tailIndent = -20.0;

    NSMutableAttributedString *attribString = [[NSMutableAttributedString alloc]initWithString:message];
    [attribString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [message length])];
    [attribString addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:12.f] range:NSMakeRange(0, [message length])];
    [attribString addAttribute:NSFontAttributeName value:[UIFont boldSystemFontOfSize:12.f] range:NSMakeRange(0, [title length])];

    UILabel *label = [[UILabel alloc] init];
    [label setAttributedText:attribString];
    [label setNumberOfLines:0];
    [label sizeToFit];
    return label;
}