如何将UIScrollView交叉淡入淡出到开头

Question

我在iPad应用程序中有一个水平滚动的分页UIScrollView,包含大量页面.在最后一页,我点击屏幕上的一个按钮重置回到第1页.我希望能够交叉解决这个过渡,但它似乎不起作用:

[UIView transitionWithView:self.view duration:1.0 options:UIViewAnimationOptionTransitionCrossDissolve|UIViewAnimationOptionAllowAnimatedContent animations:^{
    pagingScrollView.contentOffset = CGPointZero;
} completion:^(BOOL finished) {
    [self refreshPages];
}];

我读到添加UIViewAnimationOptionAllowAnimatedContent将允许所有内容转换,但它不起作用.相反,屏幕交叉溶解为背景颜色,转换完成后,第一页就会出现.

Answer 1

你不能淡出UIView(滚动条)并同时淡入相同的视图......

你可以使用不同的UIViews ......

你能做的是:

1)fadeOut当前位置的滚动条(到backGround)

2)当滚动条不可见时,将其移动到正确的位置(没有动画)

3)淡出来自backGround的滚动条

就像是:

// START FIRST PART OF ANIMATION
[UIView animateWithDuration:0.5 delay:0.0 options: options:UIViewAnimationOptionTransitionCrossDissolve|UIViewAnimationOptionAllowAnimatedContent animations:^{
    pagingScrollView.alpha = 0;


} completion:^(BOOL finished) {

// FIRST PART ENDED
// MOVE SCROLLER (no animation)
    pagingScrollView.contentOffset = CGPointZero;

// START SECOND PART OF ANIMATION
[UIView animateWithDuration:0.5 delay:0.0 options: options:UIViewAnimationOptionTransitionCrossDissolve|UIViewAnimationOptionAllowAnimatedContent animations:^{
// fadeIn - animated
    pagingScrollView.alpha = 1;
} completion:^(BOOL finished) {

// ANIMATION ENDED
    [self refreshPages];
}];



}];

新编辑:

感谢amadour,他用他的评论教我一些东西,

我希望他能加上他自己的答案,我会投票支持他

无论如何,回答jowie原始问题:

我得到了正确的动画,只是将contentOffset设置移出动画块,并删除UIViewAnimationOptionAllowAnimatedContent(不是真的需要),并将pagingScrollView作为transitionWithView的参数传递

这对我有用:

    pagingScrollView.contentOffset = CGPointZero;
    [UIView transitionWithView:pagingScrollView duration:3.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
//        pagingScrollView.contentOffset = CGPointZero; // move up, outside of animation block
    } completion:^(BOOL finished) {
        NSLog(@"-->> END amimation");
        [self refreshPages];
    }];