Cocoa: How to create buttons without Interface Builder

In Cocoa application it is possible to create controls in the run-time. The application delegate class, automatically generated by Xcode, contains method -applicationDidFinishLaunching. This is a good place to create and initialize such user interface controls.
For example, the following code creates an NSButton object in the left-bottom corner of the application window:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification 
{
    NSRect frame = NSMakeRect(10, 40, 90, 40);
    NSButton* pushButton = [[NSButton alloc] initWithFrame: frame];
    pushButton.bezelStyle = NSRoundedBezelStyle;
    [self.window.contentView addSubview: pushButton];
    
    pushButton.target = self;
    pushButton.action = @selector(buttonClicked:);
    
    [pushButton release];
}

- (IBAction) buttonClicked: (id)sender
{
    NSLog(@"Calling -buttonClicked: with sender: %@", sender);
}

Add method -(IBAction) buttonClicked: (id)sender to the header file of the application delegate, build and launch the application:

In the console you will see the logging message from the -buttonClicked each time you press on the button:

Loading program into debugger…

Program loaded.

run

[Switching to process 22626]

Running…

2010-07-03 10:52:13.424 ButtonWithoutIB[22626:a0f] Calling -buttonClicked: with sender:

2010-07-03 10:52:14.088 ButtonWithoutIB[22626:a0f] Calling -buttonClicked: with sender:

2010-07-03 10:52:15.088 ButtonWithoutIB[22626:a0f] Calling -buttonClicked: with sender:

2010-07-03 10:52:15.288 ButtonWithoutIB[22626:a0f] Calling -buttonClicked: with sender:

In case someone needs, it is possible to press on this button from the code too. Let's send -performClick message to our button from the code. Add this line before the button release:

[pushButton performClick:self];

Now the logging message appears in console when the application starts up:

Same way will work for NSPopUpButton:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification 
{
    NSRect frame = NSMakeRect(10, 40, 120, 40);
    NSPopUpButton* popUpButton = [[NSPopUpButton alloc] initWithFrame:frame];
    [self.window.contentView addSubview:popUpButton];
    
    [popUpButton addItemWithTitle: @"First"];
    [popUpButton addItemWithTitle: @"Second"];
    [popUpButton addItemWithTitle: @"Third"];
    
    NSLog( @"popUpButton itemArray: %@", popUpButton.itemArray );
    NSLog( @"popUpButton itemTitles: %@", popUpButton.itemTitles );
    
    popUpButton.target = self;
    popUpButton.action = @selector( itemDidChange: );
    
    [popUpButton release];
}

- (IBAction)itemDidChange:(id)sender
{
    NSLog( @"selected item: %@", [sender selectedItem] );
    NSLog( @"selected index: %i", [sender indexOfSelectedItem] );
    NSLog( @"selected title: %@", [sender titleOfSelectedItem] );
}

The source code in this article is from the nice book about Cocoa: "Cocoa and Objective-C Up and Running".