Lost in NSButton types and alternate images

I’d like to have an NSButton w开发者_StackOverflow中文版ith an image and an alternate image. The alternate image should be displayed while the button is being pressed and I’d also like to display the alternate image from code, calling something like [button setSelected:YES]. Is this possible without monkeing with the alternateImage property by hand?

---

This is possible without manually changing the button's image:

In Interface Builder (xib/nib Editor) set the Type of NSButton to "Toggle" and the image will automatically change to the alternate image/title.

---

You can use a NSButton with type set to NSToggleButton and then switch between the image and the alternateImage using the NSOnState / NSOffState states of the NSButton.

NSButton* theButton = [[NSButton alloc] initWithFrame:....];
theButton.image = .....
theButton.alternateImage = .....
theButton.state = NSOffState; // displays the image
theButton.state = NSOnState; // displays the alternateImage

---

The easiest way is to switch between the two images:

@implementation NSButton (Select)

- (void) setSelected: (BOOL) yn
{
    NSImage *const tmp = [self image];
    [self setImage:[self alternateImage]];
    [self setAlternateImage:tmp];
}

@end

---

I just built all 10 types of buttons in the interface editor's attribute inspector with no added coding. Here are the results:

button type	while held down	when released
Momentary Push-In	first image darkened	first image
Momentary Light	first image darkened	first image
Momentary Change	ALT IMAGE	first image
Push On / Push Off	first image darkened	first image
On / Off	first image darkened	first image
Toggle	ALT IMAGE	ALT IMAGE
Switch	ALT IMAGE	ALT IMAGE
Radio (not valid)
Accelerator	first image darkened	first image
Multi Level Acc.	first image darkened	first image

Toggle and Switch will revert to the original image when pressed again. (If you change the button type to Radio in the button's Attribute Inspector, it reverts to Switch.)