Selecting and Unlocking Levels - Learn SpriteBuilder for iOS Game Development - page 263

#import "GameScene.h"
#import "GameState.h"
Locate the presentGameScene method. Replace its contents with Listing 8-12 .
Listing 8-12 . Presenting GameScene and loading the current level
+(void) presentGameScene
{
CCScene* scene = [CCBReader loadAsScene:@"GameScene"];
GameScene* gameScene
= (GameScene*)scene.children.firstObject;
int levelNumber = [GameState
sharedGameState].currentLevel;
NSString* level = [NSString stringWithFormat:@"Levels/
Level%i",
levelNumber];
[gameScene loadLevelNamed:level];
id t = [CCTransition
transitionPushWithDirection:CCTransitionDirectionLeft
duration:1.0];
[[CCDirector sharedDirector] presentScene:scene
withTransition:t];
}
The GameScene is loaded, as usual, using the CCBReader 's loadAsScene: method.
I've mentioned this before, but it's worth noting again: the loadAsScene: method re-
turns a generic CCScene object whose only child is always the root node of the CCB that
was loaded. In this case, it's an instance of the GameScene class.
The current level number is then converted to a string of the format Levels/Level%i .
For example, the resulting string will be Levels/Level1 for the first level or
Levels/Level2345 for the 2,345 th level.
Tip Developers still frequently pad file names with additional zeros to fight a
long-won battle: numeric sorting. If you feel tempted to format numbered items
by padding with zero—for instance, Level0001 —because you might have up
to a thousand levels, please don't! Modern operating systems are well aware of