Question

我有9张图片需要交叉淡入淡出。我尝试用imageview的animationImages方法做动画。但不幸的是，它不支持图像之间的交叉淡入淡出效果。有谁能告诉我如何实现这个目标？

Answer 1

我通常使用Core Animation，特别是CABasicAnimation，

我最近使用了这个，带有几个手势识别器的图像视图，用于左右滑动。看看我正在使用的褪色动画：

_someImageView = [[UIImageView alloc] initWithFrame:myFrame];
_someImageView.image = [myArrayOfImages objectAtIndex:0];
[self.view addSubview:_someImageView];
[_someImageView release];

_currentImageIndex = 0;

_someImageView.userInteractionEnabled = YES;

UISwipeGestureRecognizer *swipeLeftGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(changeImage:)];
swipeLeftGesture.direction = UISwipeGestureRecognizerDirectionLeft;
[_someImageView addGestureRecognizer:swipeLeftGesture];
[swipeLeftGesture release];

UISwipeGestureRecognizer *swipeRightGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(changeImage:)];
swipeRightGesture.direction = UISwipeGestureRecognizerDirectionRight;
[_someImageView addGestureRecognizer:swipeRightGesture];
[swipeRightGesture release];

然后每当我滑动时调用它，或者如果你喜欢做基于时间的事情，那么让你的计时器调用它，只需确保你增加一个计数器，以便你可以循环图像：

- (void)changeImage:(UISwipeGestureRecognizer *)swipe{

    NSArray *images = [myArrayOfImages images];
    NSInteger nextImageInteger = _currentImageIndex;


    if(swipe.direction == UISwipeGestureRecognizerDirectionLeft)
        nextImageInteger++;
    else
        nextImageInteger--;


    if(nextImageInteger < 0)
        nextImageInteger = images.count -1;
    else if(nextImageInteger > images.count - 1)
        nextImageInteger = 0;

    _currentImageIndex = nextImageInteger;

    UIImage *target = [images objectAtIndex:_currentImageIndex];

    CABasicAnimation *crossFade = [CABasicAnimation animationWithKeyPath:@"contents"];
    crossFade.duration      = 0.5;
    crossFade.fromValue     = _someImageView.image;
    crossFade.toValue       = target;
    [_someImageView.layer addAnimation:crossFade forKey:@"animateContents"];
    _someImageView.image = target;
}

Answer 2

只需创建两个图像视图并将它们叠放在一起。当您想要交叉渐变到下一个图像时，只需将底部图像视图的图像设置为要淡化到的图像，并将顶部图像视图的alpha设置为0.将其冲洗并重复。 / p>

Answer 3

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
UIImage *img=[UIImage imageNamed:@"images.jpeg"];
imgview=[[UIImageView alloc]init];
imgview.frame=CGRectMake(30,90, img.size.width, img.size.height);
[self.view addSubview:imgview];
[self animateImages];
}
- (void)animateImages
{
static int count = 0;
NSArray *animationImages = @[[UIImage imageNamed:@"images.jpeg"], [UIImage imageNamed:@"images (1).jpeg"]];
UIImage *image = [animationImages objectAtIndex:(count % [animationImages count])];

[UIView transitionWithView:imgview
                  duration:2.0f // animation duration
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{
                    imgview.image = image;
                } completion:^(BOOL finished) {
                    [self animateImages];
                    count++;
                }];
}

iOS在图像视图中交叉淡化多个图像

3 个答案: