[questions] SegmentedControl, NSString, Right button

[vieestchien]

I am using toolchain to develop an application, but currently I've hit some obstacles. I have several questions and hope you guys can give me some pointers:

1) How to determine if the user has selected a segment in a UISegmentedControl? The selectedSegment method will give segmentation fault at run time if I don't select any segment, and apparently there is not an isSelected method or something similar in the UISegmentedControl.h

2) I want to make sure that my string only contains digits and alphabets. For now my only solution is to do a "find string within string" operation for all special characters I can think of, but it surely is not the most elegant solution out there. Anyone has a better idea? Is there a way to disable special characters in the keyboard, or to trim them all off my string?

3) How to make the rightButton beside a UITextField to appear? I can make the clear button to appear by calling setClearButtonStyle, but setRightButtonStyle doesn't work, and setRightButton doesn't seem to exist.

Thank you

[NetMage]

For #1, this seems to imply you can use setDelegate: and get a segmentedControl:selectedSegmentChanged: message:

#91844 - Pastie

For #2, you could filter strings with a help message like this:

@implementation NSString (SCW)

- (NSString*) stringWithCharactersInSet: (NSCharacterSet*)aSet {
    NSScanner *sc = [NSScanner scannerWithString: self];
    NSMutableString *ans = [NSMutableString stringWithCapacity: (int)([self length]*0.9)];

    while (![sc isAtEnd]) {
	NSString *work = @"";
	if ([sc scanCharactersFromSet: aSet intoString: &work])
	    [ans appendString: work];

	[sc scanUpToCharactersFromSet: aSet intoString: NULL];
    }

    return [NSString stringWithString: ans];
}

@end