Game->打砖块（源码：详解）

#import <UIKit/UIKit.h>
 @interface ViewController : UIViewController
 @property (strong, nonatomic) IBOutletCollection(UIImageView) NSArray *blockImageArray;
 @property (weak, nonatomic) IBOutlet UIImageView *paddleImage;
@property (weak, nonatomic) IBOutlet UIImageView *ballImage;
@end

@interface ViewController ()
{
//用这个布尔值标示游戏是否正在进行中
BOOL isPlaying ;
  //加一个游戏时钟
CADisplayLink *_gameTimer;
//小球移动的速度
CGPoint _speed;
//手指移动位置的差值
CGFloat chaX;
 }
//1.检测屏幕碰撞
-(BOOL)checkWithScreen;
 //2.砖块碰撞检测
 -(BOOL)checkWithBlock;
 //3.挡板碰撞
 -(void)checkWithPandle;
@end
  @implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
 }
#pragma mark 1 之前进行了页面的布局
//开始游戏
-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
//游戏是否在进行中，如果游戏还没有开始就让游戏开始
if(!isPlaying){
    isPlaying = YES;
    //初始化一个游戏时钟，让step方法1/60秒执行一次
    _gameTimer = [CADisplayLink displayLinkWithTarget:self selector:@selector(step)];
    //将游戏放在runloop中
    /*
     *
     *runLoop做两件事情
     1.监听输入源，一般自动放到runLoop中
     2.监听定时器，一般需手动放到runLoop中
     */
   //[_gameTimer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [_gameTimer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    //给小球一个初始的速度
    _speed = CGPointMake(0, -5);
   }
else
   {
    chaX = 0;
    }
}
#pragma mark 2  让小球动起来
 //让小球按照1/60的频率动起来
 -(void)step{
 // 如果返回值是yes就代表游戏失败
if ([self checkWithScreen]) {
    [self gameOver:@"再来一次"];
}
if ( [self checkWithBlock]) {
    [self gameOver:@"你真棒"];
}
[self checkWithPandle];
//小球每次的移动都是以上一次的位置作为参考
_ballImage.center = CGPointMake(_ballImage.center.x+_speed.x, _ballImage.center.y+_speed.y);
 }
#pragma mark 3  碰撞检测
 //1.检测屏幕碰撞
-(BOOL)checkWithScreen
{
BOOL isFail = NO;
//CGRectGetMInY  获取到小球的最小Y值
//1.顶部碰撞
if (CGRectGetMinY(_ballImage.frame) <= 0)
{
    //获取到绝对值
    _speed.y = fabsf(_speed.y);
}
//2.底部碰撞
if (CGRectGetMaxY(_ballImage.frame) >= (CGRectGetHeight(self.view.frame))) {
    isFail = YES;
}
//3左侧碰撞
if (CGRectGetMinX(_ballImage.frame) <= 0) {
    _speed.x = fabsf(_speed.x);
}
//4.右侧碰撞
if (CGRectGetMaxX(_ballImage.frame) >= CGRectGetWidth(self.view.frame)) {
    _speed.x = -1*fabsf(_speed.x);
}
return isFail;
}
 //2.检测板子是否碰撞
-(BOOL)checkWithBlock
{
BOOL gameWin = YES;
//通过for循环找到小球跟哪个色块碰撞了
for (UIImageView *block in _blockImageArray) {
    //CGRectIntersectsRect判断；两个视图是否碰撞
    if (CGRectIntersectsRect(block.frame , _ballImage.frame) && !block.hidden) {
        block.hidden = YES;
        _speed.y = fabsf(_speed.y);
    }
}
//判断所有的砖块是否都被隐藏了
for (UIImageView *block in _blockImageArray ) {
    if (block.hidden == NO) {
        gameWin = NO;
        break;
    }
}
return gameWin;
}
//3.挡板碰撞检测
  -(void)checkWithPandle
{
if(CGRectIntersectsRect(_ballImage.frame,_paddleImage.frame))
{
    _speed.y = -1*fabsf(_speed.y);
    //让小球的X方向的速度跟手指瞬时移动的速度相加
    _speed.x += chaX;
    NSLog(@"speed.x= %f",_speed.x);
}
}
-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
 {
if (isPlaying) {
    //后去我点击的手指，touches是个集合，视图有多点触摸
    UITouch *touch = [touches anyObject];
    //获取到当前手指x的值
    CGFloat nowX = [touch locationInView:self.view].x;
    //获取到上一次手指x的值
    CGFloat lastX = [touch previousLocationInView:self.view].x;
    chaX = nowX -lastX;
    //让挡板移动
    _paddleImage.center = CGPointMake(_paddleImage.center.x+chaX,_paddleImage.center.y);
}
}
#pragma mark  从底部掉下去，游戏结束
-(void)gameOver:(NSString *)string
{
isPlaying = NO;
NSLog(@"%@",string);
//销毁定时器
[_gameTimer invalidate];
for (UIImageView *block in _blockImageArray) {
    block.hidden = YES;
    block.alpha = 0;
}
[UIView animateWithDuration:2.0 animations:^{
    for (UIImageView *block in _blockImageArray){
        block.hidden = NO;
        block.alpha = 1;
    }
}completion:^(BOOL finshed){
    _ballImage.center = CGPointMake(160, 377);
    _paddleImage.center = CGPointMake(160, 397);
}];
}
 - (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end