适应不同的设备

CCSpriteBatchNode *chapter2SpriteBatchNode;  
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {  
    [[CCSpriteFrameCache sharedSpriteFrameCache]  addSpriteFramesWithFile:@"scene1atlas.plist"]; // 3.1  
    chapter2SpriteBatchNode = [CCSpriteBatchNode  batchNodeWithFile:@"scene1atlas.png"]; // 3.2  
} else {  
    [[CCSpriteFrameCache sharedSpriteFrameCache]  addSpriteFramesWithFile:@"scene1atlasiPhone.plist"];// 3.1  
    chapter2SpriteBatchNode = [CCSpriteBatchNode  batchNodeWithFile:@"scene1atlasiPhone.png"]; // 3.2  
}