User Interaction - Core Animation - page 183

delegate to the AppDelegate . This enables the AppDelegate to receive mouseUp and
mouseDown events from contentView .

Building the Layers
After launching, the application builds the interface layers before presenting the window
to the user. The best way to do this is to implement the -awakeFromNib method in the
AppDelegate class, as shown in Listing 11-7. This method is called before the application
renders anything onscreen and is processed as the application starts up. We want to set
up everything before display to avoid an ugly redraw as the application appears on screen.

LISTING 11-7 AppDelegate -awakeFromNib implementation

- ( void )awakeFromNib
{

NSView *contentView = [ window contentView ];
[contentView setWantsLayer : YES ];
CALayer *contentLayer = [contentView layer ];
[contentLayer setBackgroundColor : kBlackColor ];

redButton = [ LZButtonLayer layer ];
[ redButton setString : @”Red” ];
[ redButton setPosition : CGPointMake (60, 22)];
[ redButton setMyColor : kRedColor ];

[contentLayer addSublayer : redButton ];

greenButton = [ LZButtonLayer layer ];
[ greenButton setString : @”Green” ];
[ greenButton setPosition : CGPointMake (200, 22)];
[ greenButton setMyColor : kGreenColor ];

[contentLayer addSublayer : greenButton ];

blueButton = [ LZButtonLayer layer ];
[ blueButton setString : @”Blue” ];
[ blueButton setPosition : CGPointMake (340, 22)];
[ blueButton setMyColor : kBlueColor ];

[contentLayer addSublayer : blueButton ];

colorBar = [ CALayer layer ];
[ colorBar setBounds : CGRectMake (0, 0, 380, 20)];
[ colorBar setPosition : CGPointMake (200, 100)];