打开HelloWorldLayer.h文件,添加以下实例变量(在@interface行的花括号之后):

NSMutableArray *towerBases;

将HelloWorldLayer.m文件修改为如下内容:

//Add a new method 
-(void)loadTowerPositions
{
    NSString* plistPath = [[NSBundle mainBundle] pathForResource:@"TowersPosition" ofType:@"plist"];
    NSArray * towerPositions = [NSArray arrayWithContentsOfFile:plistPath];
    towerBases = [[NSMutableArray alloc] initWithCapacity:10];

    for(NSDictionary * towerPos in towerPositions)
    {
        CCSprite * towerBase = [CCSprite spriteWithFile:@"open_spot.png"];
        [self addChild:towerBase];
        [towerBase setPosition:ccp([[towerPos objectForKey:@"x"] intValue],[[towerPos objectForKey:@"y"] intValue])];
        [towerBases addObject:towerBase];
    }

}

//In init,call this new method in section #3
// 3 - Load tower positions
[self loadTowerPositions];

编译运行app,你将看到道路周围的矩形底座,它们充当了玩家炮塔的基座.

现在炮塔基座已经就绪,号召我们建立装备和建立炮塔!

首先,打开HelloWorldLayer.h文件,添加一个属性(在闭花括号之后):

@property (nonatomic,strong) NSMutableArray *towers;

在HelloWorldLayer.m中@implementation行下面同步towers属性:

@synthesize towers;

在高版本的Xcode中同步属性已经不再需要.(猫猪注)