ios - 如何使用动画在 x 方向上延长 UISearchBar？

Question

我想用动画将右侧搜索栏向左延长 20 像素，将左侧搜索栏向右缩短 20 像素。我该怎么做？

CGRect leftFrame = self.leftSearchBar.frame;
    //leftFrame.origin.x = leftFrame.origin.x - 20;
    leftFrame.size.width = leftFrame.size.width - 40;

    CGRect rightFrame = self.rightSearchBar.frame;
    rightFrame.origin.x = rightFrame.origin.x - 40;
    rightFrame.size.width = rightFrame.size.width + 40;

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    [UIView setAnimationDelay:0.0];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];

    self.leftSearchBar.frame = leftFrame;
    self.rightSearchBar.frame = rightFrame;

    [UIView commitAnimations];

这是行不通的。它首先调整没有动画的 View 大小，然后移动带有动画的右 View 。

Answer 1

假设您没有更改 anchor 或类似内容，只需扩大宽度即可使其向右拉伸(stretch)。将它包装在一个 UIView 动画 block 中，它应该根据问题中的规范进行动画处理，如下所示:

UISearchBar* searchbar = ...; // However you've created your UISearchBar, we'll refer to it as 'searchbar'

CGRect searchFrame = searchbar.frame;
[UIView animateWithDuration:0.8 
                      delay:0.0
                    options:UIViewAnimationOptionBeginFromCurrentState
                 animations:^{
                     searchFrame.size.width += 30;
                     searchbar.frame = searchFrame;
                 }
                 completion:nil];

您需要确保 += 30 不会被多次调用，否则您将每次扩展 30 个点叫做。如果您事先知道大小，则可以简单地将其替换为 = size + 30，这是一个更安全的选择，以防您多次调用动画。