CreatePlugin - mac-carfrontend - How to create a CarFrontEnd plugin

#import <Cocoa/Cocoa.h>
#import <CarFrontEndAPI/CarFrontEndAPI.h>

@interface SamplePlugin : NSObject <CarFrontEndProtocol> {
    id                  owner;
    IBOutlet NSView     *samplePluginView;
}

- (id) initWithPluginManager: (id) pluginManager;
- (NSString *) name;
- (void) initalize;
- (NSImage *) pluginButtonImage;
- (NSView *) contentViewForSize: (NSSize) size;
- (void) removePluginFromView;

- (IBAction) buttonClicked: (id) sender;

@end

Edit the class file

Add a static variable outside the @implementation section.

This will allow you to apply the Singleton pattern to the object.
The init method will be called twice. Once when the plugin is loaded and once when you load your NIB file.

Add an init method to setup your object.

Make sure to use your static variable so that there is only ever one instance of your object.

Add the protocol methods to the @implementation.
Add the code for your action method.

Your object file should look something like:

#import "SamplePlugin.h"

static SamplePlugin *sharedSP = nil;

@implementation SamplePlugin

- (id) init {
    return([self initWithPluginManager:nil]);
}

- (id) initWithPluginManager: (id) pluginManager {
    if (sharedSP != nil) {
        [self release];
        return(sharedSP);
    }
    
    [super init];
    owner = [pluginManager retain];
    
    // Setup for a single instance.
    sharedSP = self;
    
    return(self);
}

- (NSString *) name {
    return(@"Sample Plugin");
}

- (void) initalize {
    // No-op for this example.
    //  Should generate the button image here rather than on demand.
}

- (NSImage *) pluginButtonImage {
	NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
    
    [attributes setObject:[NSFont fontWithName:@"Helvetica" size:26]
                   forKey:NSFontAttributeName];
	[attributes setObject:[NSColor whiteColor]
                   forKey:NSForegroundColorAttributeName];
    
    NSSize          size = [[self name] sizeWithAttributes:attributes];
    NSImage         *image = [[[NSImage alloc] initWithSize:size] autorelease];
    
    [image lockFocus];
    [[self name] drawAtPoint:NSZeroPoint withAttributes:attributes];
    [image unlockFocus];
    
    return(image);
}

- (NSView *) contentViewForSize: (NSSize) size {
    // We are ignoring the size value, but it is there incase you have differnt
    //  views based on the size that CarFrontEnd sends you.
    if (samplePluginView == nil) {
        [NSBundle loadNibNamed:@"SamplePlugin" owner:self];
    }
    
    return(samplePluginView);
}

- (void) removePluginFromView {
    // No-op
    //  If you need to do something when your view is no longer displayed,
    //  add the code here.
}

- (IBAction) buttonClicked: (id) sender {
    if ([[sender stringValue] isEqualToString:@"Click"]) {
        [sender setStringValue:@"Clock"];
    } else if ([[sender stringValue] isEqualToString:@"Clock"]) {
        [sender setStringValue:@"Click"];
    }
}

@end

Add a NIB file to your project and make sure that it uses the name that you used in your -contentViewForSize: method ("SamplePlugin" in the example).

Read your object's header file into the NIB file.
Instantiate your object.
Add a NSView to your NIB file and link it to your NSView outlet.
Add a NSButton to your NSView.

Set it's string value to "Click".
Set it's action to the -buttonClick: method of you object.

Edit your project's Info.plist

Set the "NSPrincipalClass" value to the name of your object.

Build your project and fix any compiler errors.

Installation

Copy the built plugin to your ~/Library/Application Support/CarFrontEnd/Plugins directory and launch CarFrontEnd. If everything went according to plan, your new plugin should be available.