如何解雇模态VC与淡出动画？ [英] How to dismiss a modal VC with fade out animation?

问题描述

我用下面的code在我的presenting VC在孩子模式的VC褪色，并能正常工作：

I am using the following code in my presenting VC to fade in the child modal VC, and this works fine:

self.infoViewController.view.alpha = 0.0;
[self.navigationController presentModalViewController:self.infoViewController animated:NO];
[UIView animateWithDuration:0.5
             animations:^{self.infoViewController.view.alpha = 1.0;}];

不过，我不能让它淡出，我已经尝试了一些事情，这是我试过，不工作的最新进展：

However I can't get it to fade out, I have tried a few things, this is the latest I tried that doesn't work:

- (IBAction)dismissAction:(id)sender
{
if ([[self parentViewController] respondsToSelector:@selector(dismissModalViewControllerAnimated:)])
{
    [[self parentViewController] dismissModalViewControllerAnimated:YES];
    self.parentViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    self.parentViewController.view.alpha = 0.0;
    [UIView animateWithDuration:0.5
                     animations:^{self.parentViewController.view.alpha  = 1.0;}];
} else 
{
    [[self presentingViewController] dismissViewControllerAnimated:YES completion:nil];
    self.presentedViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    self.presentedViewController.view.alpha = 0.0;
    [UIView animateWithDuration:0.5
                     animations:^{
                         self.presentedViewController.view.alpha  = 1.0;}];
}

}

模态视图控制器淡出，但马上，在不喜欢它的时间周期时，其显示出来。

The modal view controller is faded out but immediately, not over a time period like it is when its displayed.

推荐答案

本（原件）不接受来自H2CO3的正确答案了。 UIModalTransitionStyleCrossDissolve 做pretty，很多正是你要寻找的效果。你只是没有设置modalTransitionStyle，直到它的后期。替换所有code具有这些功能的存在各自的立场：

This (original part) is not to take away from H2CO3's correct answer. UIModalTransitionStyleCrossDissolve does pretty-much exactly the effect you're looking for. You are just not setting the modalTransitionStyle until it's to late. Replace all of your code with these functions in there respective positions:

-(void)show{
    self.infoViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    [self presentModalViewController:self.infoViewController animated:YES];
}
- (IBAction)dismissAction:(id)sender{
    [self dismissModalViewControllerAnimated:YES];
}

修改响应时间是一个问题：让我们来谈谈违规code。我们将专注于只是如果属实的部分，因为它给其他基本相同。

Edit in response to timing being an issue: Let's talk about the offending code. We'll concentrate on just the if true part, since it's essentially identical to the else.

[[self parentViewController] dismissModalViewControllerAnimated:YES];
self.parentViewController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
self.parentViewController.view.alpha = 0.0;
[UIView animateWithDuration:0.5
                 animations:^{self.parentViewController.view.alpha  = 1.0;}];

如果你正在寻找一个互惠的动画，这不是它。在您的原创动画，你的下一个视图的Alpha设置为0，那么presented下一个视图控制器，然后设置它的视图的alpha为1。所以，逻辑上你需要关闭该动画后视图控制器;这是很容易使用的块。在code会是这个样子：

If you're looking for a reciprocal animation this isn't it. In your original animation you set the next view's alpha to 0, then presented the next view controller, then set it's view's alpha to 1. So logically you need to dismiss the view controller after the animation; This is really easy using blocks. The code would look something like this:

[UIView animateWithDuration:0.5 animations:^{
    self.view.alpha = 0;
} completion:^(BOOL b){
    [self.presentingViewController dismissModalViewControllerAnimated:NO];
    self.view.alpha = 1;
}];

code此行动画视图的alpha为0，则（完成后）驳回了presented视图控制器，并将视图的Alpha回到1.这是一个互惠的动画。

This line of code animates the view's alpha to 0, then (upon completion) dismisses the presented view controller, and sets the view's alpha back to 1. This is a reciprocal animation.

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