iOS 展示 gif

gif 图 是多张依次有连续动作的图 顺时间展示的一种动态效果图 . 有的是均匀时间更换下一张 有的 则不是均匀时间变化

1. 那么 对于均匀 时间变化的gif图 比较适合 使用 iOS 系统自带方法 imageView 的动态展示图片的方法就好

如:

NSMutableArray *array=[NSMutableArray arrayWithCapacity:0];
for(int i=1;i   < 10;i++)
{
NSString *str=[NSString stringWithFormat:@"Nav_Bg%d.png",i];
UIImage *image=[UIImage imageNamed:str];
[array addObject:image];
}
UIImageView *imageView=[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];
imageView.animationImages=array;
imageView.animationDuration=1.5;//duration :持续 持续时间
imageView.animationRepeatCount=1 ;//重复次数
[self .window addSubview:imageView];
[imageView startAnimating];

以上code 表达的是 10张图 在 1.5的时间 只执行一次动画展示(不循环重复) 所以关键 是这个 1.5秒 需要表达10张图 正常一次执行的时间即可出现效果比较好的动画

2. 不确定时间gif

上述方法 是按照 给定的常量时间 1.5s 执行gif 时间, 这样的弊端 是 如果把当前方法作为通用的类方法的话,这个1.5s 很不科学 . 所以 下边的方法是首先计算图片的总时间长度 .再执行动画.

#import <UIKit/UIKit.h>
@interface MotionActiveAgeGif : UIView
{
UIImageView *gitView;
}
@property (nonatomic ,strong) UIImageView *gitView;
@property (nonatomic ,strong)UIImageView * lastGifView;
//@property (nonatomic ,strong)NSString * gifName;
- (instancetype)initWithName:(NSString *)gifName andFrame:(CGRect)frame ;
@end

#import "MotionActiveAgeGif.h"

#import <ImageIO/ImageIO.h>
#import <QuartzCore/CoreAnimation.h>

//#define DuringTime  1.5f
@interface MotionActiveAgeGif ()
{
float totalTime ;
CADisplayLink *displayLink ;
}
@end
@implementation MotionActiveAgeGif
@synthesize gitView ;
@synthesize lastGifView ;
- (instancetype)initWithName:(NSString *)gifName andFrame:(CGRect)frame
{
self = [super init];
if (self) {
totalTime = 0;
gitView = [[UIImageView alloc]initWithFrame:frame];
lastGifView =  [[UIImageView alloc]initWithFrame:gitView.frame];
NSURL *url = [[NSBundle mainBundle] URLForResource:[NSString stringWithFormat:@"%@.gif",gifName] withExtension:nil];
CGImageSourceRef csf = CGImageSourceCreateWithURL((__bridge CFTypeRef) url, NULL);
size_t const count = CGImageSourceGetCount(csf);
UIImage *frames[count];
CGImageRef images[count];

NSMutableArray *delayTimes = [NSMutableArray array];
for (size_t i = 0; i < count; ++i) {
images[i] = CGImageSourceCreateImageAtIndex(csf, i, NULL);
UIImage *image =[[UIImage alloc] initWithCGImage:images[i]];
lastGifView.image = image ;
frames[i] = image;

//CFBridgingRelease 给予arc所有权
NSDictionary *dict = (NSDictionary*)CFBridgingRelease(CGImageSourceCopyPropertiesAtIndex(csf, i, NULL));
NSLog(@"kCGImagePropertyGIFDictionary %@", [dict valueForKey:(NSString*)kCGImagePropertyGIFDictionary]);
//
NSDictionary *gifDict = [dict valueForKey:(NSString*)kCGImagePropertyGIFDictionary];
[delayTimes addObject:[gifDict valueForKey:(NSString*)kCGImagePropertyGIFDelayTime]];

if (totalTime >= 0)
{
totalTime = totalTime + [[gifDict valueForKey:(NSString*)kCGImagePropertyGIFUnclampedDelayTime] floatValue];
}
NSLog(@"%lf",totalTime);

CFRelease(images[i]);
}
UIImage *const animation = [UIImage animatedImageWithImages:[NSArray arrayWithObjects:frames count:count] duration:totalTime];
gitView.image = animation;
gitView.animationRepeatCount =1;  //动画重复次数1  不起作用
[gitView startAnimating];
[self addSubview:gitView];
self.frame = gitView.frame;

[self performSelector:@selector(stopGifView) withObject:nil afterDelay:totalTime];
CFRelease(csf);
}
return self;
}
- (void)stopGifView
{
[gitView removeFromSuperview];
[self addSubview:lastGifView];
}