iOS實(shí)現(xiàn)大雪紛飛動(dòng)畫

更新時(shí)間：2018年06月22日 10:07:02 作者：桂雛菊

這篇文章主要為大家詳細(xì)介紹了iOS實(shí)現(xiàn)大雪紛飛動(dòng)畫，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

本文實(shí)例為大家分享了iOS實(shí)現(xiàn)大雪紛飛動(dòng)畫的具體代碼，供大家參考，具體內(nèi)容如下

1.結(jié)果展示

美麗的雪花，勾起了多少美好的回憶。

2.制作思路

其實(shí)創(chuàng)作這樣一個(gè)大學(xué)紛飛的場景是十分簡單的，簡單到你看了教程之后想不會(huì)都不行。OK，下面國際慣例，講解一下思路吧。

1.創(chuàng)建一個(gè)數(shù)組用來保存大量的雪花

_imagesArray = [[NSMutableArray alloc] init];
  for (int i = 0; i < 1000; ++ i) {
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snow"]];
    float x = IMAGE_WIDTH;
    imageView.frame = CGRectMake(IMAGE_X, -30, x, x);
    imageView.alpha = IMAGE_ALPHA;
    [self.view addSubview:imageView];
    [_imagesArray addObject:imageView];
  }

2.使用時(shí)鐘（CADisplayLink）來控制下雪，為什么不使用NSTimer呢。其實(shí)是可以的，只是（CADisplayLink）刷幀更快一些。

//創(chuàng)建時(shí)鐘，并且添加到主循環(huán)中
CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(makeSnow)];
[link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];

3.下雪，就是把數(shù)組當(dāng)做隊(duì)列來使用。

每次從數(shù)組頭部取出一個(gè)雪花并且刪除其在數(shù)組中的占位。
讓雪花飄落，通過UIView動(dòng)畫完成frame，transform等改變。
當(dāng)動(dòng)畫完成之后，將取出的雪花再次放進(jìn)數(shù)組的尾部

- (void)makeSnow
{
  if (_imagesArray.count > 0) {
    UIImageView *imageView = _imagesArray[0];
    [_imagesArray removeObjectAtIndex:0];
    [self snowFall:imageView];
  }
}

- (void)snowFall:(UIImageView *)imageView
{
  [UIView animateWithDuration:10 animations:^{
    imageView.frame = CGRectMake(imageView.frame.origin.x, Main_Screen_Height, imageView.frame.size.width, imageView.frame.size.height);
    imageView.transform = CGAffineTransformMakeScale(0.3, 0.3);
    imageView.transform = CGAffineTransformRotate(imageView.transform, M_PI);
  } completion:^(BOOL finished) {
    float x = IMAGE_WIDTH;
    imageView.frame = CGRectMake(IMAGE_X, -30, x, x);
    [_imagesArray addObject:imageView];
  }];
}

3.有代碼有真相

#define IMAGE_X        arc4random()%(int)Main_Screen_Width
#define IMAGE_ALPHA      ((float)(arc4random()%10))/10
#define IMAGE_WIDTH      arc4random()%20 + 10
#define PLUS_HEIGHT      Main_Screen_Height/25

#define Main_Screen_Height   [[UIScreen mainScreen] bounds].size.height
#define Main_Screen_Width    [[UIScreen mainScreen] bounds].size.width

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic ,strong) NSMutableArray *imagesArray;
@property (nonatomic , strong) UIImageView *imageView;
@end

@implementation ViewController

- (void)loadView
{
  UIImageView *imageView = [[UIImageView alloc]initWithFrame:[UIScreen mainScreen].bounds];
  imageView.image = [UIImage imageNamed:@"backgound.jpg"];
  imageView.contentMode = UIViewContentModeScaleAspectFill;
  self.view = imageView;

}

- (void)viewDidLoad
{
  [super viewDidLoad];

  _imagesArray = [[NSMutableArray alloc] init];
  for (int i = 0; i < 1000; ++ i) {
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"snow"]];
    float x = IMAGE_WIDTH;
    imageView.frame = CGRectMake(IMAGE_X, -30, x, x);
    imageView.alpha = IMAGE_ALPHA;
    [self.view addSubview:imageView];
    [_imagesArray addObject:imageView];
  }

  //創(chuàng)建時(shí)鐘，并且添加到主循環(huán)中
  CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(makeSnow)];
  [link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
}


- (void)makeSnow
{
  if (_imagesArray.count > 0) {
    UIImageView *imageView = _imagesArray[0];
    [_imagesArray removeObjectAtIndex:0];
    [self snowFall:imageView];
  }
}

- (void)snowFall:(UIImageView *)imageView
{
  [UIView animateWithDuration:10 animations:^{
    imageView.frame = CGRectMake(imageView.frame.origin.x, Main_Screen_Height, imageView.frame.size.width, imageView.frame.size.height);
    imageView.transform = CGAffineTransformMakeScale(0.3, 0.3);
    imageView.transform = CGAffineTransformRotate(imageView.transform, M_PI);
  } completion:^(BOOL finished) {
    float x = IMAGE_WIDTH;
    imageView.frame = CGRectMake(IMAGE_X, -30, x, x);
    [_imagesArray addObject:imageView];
  }];
}

4.Demo也不能少

下載地址：snow

以上就是本文的全部內(nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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