CODEWITHSUNDEEP
objective-ccocoainterface-builder
aneuryzm
aneuryzm

Reputation: 64854

How to disable a NSMenuItem when the binded NSArrayController selection is multiple?

This is how I enable/disable a NSMenuItem depending on the selection of items in a NSArrayController.

enter image description here

However I would like to disable the NSMenuItem in one more case: when the selection is multiple. In other terms, if more than one item is selected it should be disabled.

Thanks

Upvotes: 1

Views: 416

Answers (2)

Christian Kienle
Christian Kienle

Reputation: 753

@bijan's transformedValue: method could be improved:

- (id)transformedValue:(id)value{

    if(value == nil)
    {
        return @(NO);
    }

    if([value respondsToSelector:@selector(unsignedIntegerValue)] == NO)
    {
        return @(NO);
    }

    NSUInteger count = [value unsignedIntegerValue];
    return @(count > 0);
}

Upvotes: 1

bijan
bijan

Reputation: 1685

You could subclass NSValueTransformer for this!

Implementation would look something like this: 

@implementation CountToEnabledTransformer


+ (Class)transformedValueClass {

    return [NSNumber class];
}
+ (BOOL)allowsReverseTransformation {

    return NO;
}
- (id)transformedValue:(id)value{

    int count = value;
    BOOL boolValue = 0;

    if ((count > 1) || (count == 0)) {
        boolValue = 0;
    }else {
        boolValue = 1;
    }

    NSNumber *boolNumber = [NSNumber numberWithBool:boolValue];



return boolNumber;
}
@end

That takes in the @count value, performs an if statement and returns an appropriate boolean value, to bind your enabled property to.

Don't forget to register your newly created NSValueTransformer sublclass:

[NSValueTransformer setValueTransformer:[[CountToEnabledTransformer alloc] init] forName:@"CountToEnabledTransformer"];

A good place to do this is - (void)applicationDidFinishLaunching, so it's already registered, when you nib tries to bind to it!

After that, just type in the NSValueTranformer's sublass name into the appropriate text field in the IB bindings inspector.

Upvotes: 0

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