帧动画与定时器动画的火焰效果
首先是使用定时器制作的火焰动画效果
1 #import "FireViewController.h" 2 3 @implementation FireViewController 4 5 - (void)viewDidLoad 6 { 7 [super viewDidLoad]; 8 9 _fireImageView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 10 [self.view addSubview:_fireImageView]; 11 _imageNameArray = [[NSMutableArray alloc] init]; //使用可变数组 12 for (int i = 1; i <= 17; i++) 13 { 14 NSString * imageName = [NSString stringWithFormat:@"Fire%d.gif", i]; 15 [_imageNameArray addObject:imageName]; 16 } 17 18 _timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(fireShow) userInfo:nil repeats:YES]; //定时器 19 20 UIButton *kaiGuan = [UIButton buttonWithType:UIButtonTypeSystem]; 21 kaiGuan.frame = CGRectMake(280, 20, 30, 30); 22 [kaiGuan setBackgroundImage:[UIImage imageNamed:@"inc_pause.png"] forState:UIControlStateNormal]; 23 kaiGuan.tag = 99; 24 [kaiGuan addTarget:self action:@selector(isContinue) forControlEvents:UIControlEventTouchUpInside]; 25 [self.view addSubview:kaiGuan]; 26 } 27 28 - (void)fireShow 29 { 30 static int count = 0; 31 32 _fireImageView.image = [UIImage imageNamed:[_imageNameArray objectAtIndex:count]]; 33 count ++; 34 35 if (count >= _imageNameArray.count) 36 { 37 count = 0; 38 } 39 } 40 41 - (void)isContinue 42 { 43 UIButton * btn = (UIButton *)[self.view viewWithTag:99]; 44 if ( _timer != nil ) //[_timer isValid] 判断定时器是都还有效 45 { 46 [_timer invalidate]; //销毁动画 47 [btn setBackgroundImage:[UIImage imageNamed:@"inc_start.png"] forState:UIControlStateNormal]; //更换按钮的显示图片 48 _timer = nil; 49 50 } 51 else 52 { 53 _timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(fireShow) userInfo:nil repeats:YES]; //重新生成一个定时器 54 [btn setBackgroundImage:[UIImage imageNamed:@"inc_pause.png"] forState:UIControlStateNormal]; 55 } 56 } 57 58 @end
下面这一段是使用帧动画实现的火焰效果图
1 #import "HUAppDelegate.h" 2 3 @implementation HUAppDelegate 4 5 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 6 { 7 self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 8 // Override point for customization after application launch. 9 self.window.backgroundColor = [UIColor whiteColor]; 10 [self.window makeKeyAndVisible]; 11 12 //创建可变数组，存放图片 13 NSMutableArray *imageArray = [[NSMutableArray alloc] init]; 14 for (int i=1; i < 18; i ++ ) 15 { 16 [imageArray addObject:[UIImage imageNamed:[NSString stringWithFormat:@"Fire%d.gif", i]]]; 17 } 18 19 UIImageView *imageView = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 20 // imageView.image = [UIImage imageNamed:@"Fire1.gif"]; //这句不可少，否则点击按钮让动画暂停的时候，出现白屏，因为此时没有图片被加载 21 imageView.tag = 22; //设置 tag 的原因是避免设置全局变量 22 23 //帧动画 24 imageView.animationImages = imageArray; //数组里存储的必须是 UIImage 的对象，即图片 25 [imageView setAnimationDuration:2]; //用来这只动画持续的时间 26 [imageView setAnimationRepeatCount:0]; //0 表示无限多次，与 UIView 里的setAnimationRepeatCount:(float)repeatCount 0（默认为不重复） 不同 27 [imageView startAnimating]; //动画开始 28 [self.window addSubview:imageView]; 29 30 //使用全屏的按钮，可以实现点击屏幕让火焰停止与继续 31 UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem]; 32 btn.frame = [UIScreen mainScreen].bounds; 33 [self.window addSubview:btn]; 34 [btn addTarget:self action:@selector(pauseOrContinue) forControlEvents:UIControlEventTouchUpInside]; 35 36 return YES; 37 } 38 39 - (void)pauseOrContinue 40 { 41 UIImageView *imageView = (UIImageView *)[self.window viewWithTag:22]; 42 // if ([imageView isAnimating]) 43 // { 44 // [imageView stopAnimating]; 45 // } 46 // 47 // else 48 // { 49 // [imageView startAnimating]; 50 // } 51 52 //还可以用另外一种方法来控制动画是否暂停与继续 53 static int count = 0; 54 count ++; 55 if (count % 2 == 1) 56 { 57 [imageView stopAnimating]; 58 } 59 else 60 { 61 [imageView startAnimating]; 62 }//这种方法更为通用一点，因为不是所有的控件都有判断其是否继续的 属性 63 } 64 65 @end
使用者两种方法制作的火焰动画在视觉效果上并没有什么区别
区别在于点击按钮时：
使用定时器 NSTimer 生成的动画，点击按钮时图片停止在当前图片，即每次停止时显示的图片有可能都不一样，因为定时器切片时时根据当前图片的计数器来决定的。
使用帧动画生成的动画，在点击按钮让动画停止时，图片总是会回到第一张图片，所以如果不设置第一张图片的话，每次点击让动画停止会出现白屏。
