ios - Objective-c 动画与尾随约束的约束不稳定问题
<p><p>我正在使用 Objective-c 开发一个 IOS 应用程序。在为 View 的约束设置动画时，我遇到了一个不稳定的问题。动画在帧的最终位置上效果很好，但随机地，第一个动画 block 省略了尾随(右)约束(左约束永远不会达到 -20 常数值)，但是前导(左)、顶部和底部约束正在按预期工作。</p>
<p>请看我上传的视频。在第一次点击中，动画按预期工作，但在第二次点击中出现问题。请指教。</p>
<p> <a href="https://youtu.be/Smh-_8urBlA" rel="noreferrer noopener nofollow">Video showing the problem</a> </p>
<pre><code>- (void)animateTransition:(nonnull id<UIViewControllerContextTransitioning>)transitionContext {
// 1
UIView *containerView = transitionContext.containerView;
UIViewController* toViewController = ;
// 2
;
if(]){
ImageViewController *vcImage = (ImageViewController*)toViewController;
vcImage.constraintLeft.constant = 20;
vcImage.constraintTop.constant = self.selectedCardFrame.origin.y + 60.0;
vcImage.constraintRight.constant = 20.0;
vcImage.constraintBottom.constant = 0;//self.CollectionView.bounds.size.height - (self.selectedCardFrame.origin.y + self.selectedCardFrame.size.height);
;
NSTimeInterval duration = ;
;
[UIView animateWithDuration:duration animations:^{
//First animation block
vcImage.constraintRight.constant = -20.0;
vcImage.constraintLeft.constant = -20.0;
vcImage.constraintTop.constant = -20.0;
vcImage.constraintBottom.constant = 0;
;
//toViewController.configureRoundedCorners(shouldRound: false)
} completion:^(BOOL finished) {
//Second animation block
[UIView animateWithDuration:duration animations:^{
vcImage.constraintLeft.constant = 0;
vcImage.constraintTop.constant = 0.0;
vcImage.constraintRight.constant = 0;
vcImage.constraintBottom.constant = 0;
;
//toViewController.configureRoundedCorners(shouldRound: false)
} completion:^(BOOL finished) {
;
}];
}];
}
</code></pre>
<p>}</p>
<p>@Sh_Khan 发表评论后更新代码。</p>
<pre><code>- (void)animateTransition:(nonnull id<UIViewControllerContextTransitioning>)transitionContext {
// 1
UIView *containerView = transitionContext.containerView;
UIViewController* toViewController = ;
// 2
;
if(]){
ImageViewController *vcImage = (ImageViewController*)toViewController;
NSTimeInterval duration = ;
[UIView animateWithDuration:0 animations:^{
vcImage.constraintLeft.constant = 20;
vcImage.constraintTop.constant = self.selectedCardFrame.origin.y + 60.0;
vcImage.constraintRight.constant = 20.0;
vcImage.constraintBottom.constant = 0;
;
} completion:^(BOOL finished) {
[UIView animateWithDuration:duration animations:^{
//First animation block
vcImage.constraintRight.constant = -20.0;
vcImage.constraintLeft.constant = -20.0;
vcImage.constraintTop.constant = -20.0;
vcImage.constraintBottom.constant = 0;
;
//toViewController.configureRoundedCorners(shouldRound: false)
} completion:^(BOOL finished) {
//Second animation block
[UIView animateWithDuration:duration animations:^{
vcImage.constraintLeft.constant = 0;
vcImage.constraintTop.constant = 0.0;
vcImage.constraintRight.constant = 0;
vcImage.constraintBottom.constant = 0;
;
//toViewController.configureRoundedCorners(shouldRound: false)
} completion:^(BOOL finished) {
;
}];
}];
}];
}
</code></pre>
<p>}</p></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>在设置您的 imageView 之前，请尝试重新定位照片。有些东西告诉我 ImageView 很难确定图像的方向。我曾经在过渡期间发生过这种情况，并会解释为什么您只在某些时候看到这种行为。我对 Objective C 有点生疏，但在设置 imageView 图像之前试一试并使用它。</p>
<pre><code>-(UIImage*)normalizeImage:(UIImage*)currentImage {
if (currentImage.imageOrientation == UIImageOrientationUp){
return currentImage;
}
UIGraphicsBeginImageContextWithOptions(currentImage.size, NO, currentImage.scale);
;
UIImage *_newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return _newImage;
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - Objective-c 动画与尾随约束的约束不稳定问题，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/50162812/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/50162812/
</a>
</p>
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