动画视图宽度，同时使用自动布局 [英] Animating view width whilst using auto layout

问题描述

我使用自动布局来定位一个自定义的进度条（其简单地用背景色一个UIView）。我不是使用适当的进度条，因为我没有想必须把它完全定制，以我的需求，当一个UIView就足够了。

反正我已经告诉过X code到放置在进度条到左边，并从底部一定的距离。这种正确的定位，但是当我动画的宽度没有任何反应。如果我创建一个新的UIView，然后动画能够正常工作。是制约$ P $从动画pventing呢？没有约束在所有放置在宽度

  [UIView的animateWithDuration：startingGameSeconds延迟：0.0选项：UIViewAnimationOptionCurveLinear
                 动画：^（无效）{
                     progressBar.frame = CGRectMake（progressBar.frame.origin.x，
                                                    progressBar.frame.origin.y，
                                                    320，
                                                    progressBar.frame.size.height）;                 }
                 完成：^（BOOL完）{
                 }];
 

解决方案

当你使用自动布局，你不应该使用被SETFRAME：方法了。当你想进行动画处理的框架，你必须动画的约束。我想你的自动布局约束在Interface Builder中定义。首先，确保你有添加到您的进度条的宽度约束布局。接下来，这个宽度布局约束创建一个IBOutlet。现在，您可以动画约束是这样的：

  [UIView的animateWithDuration：1.F动画：^ {
   [自progressBarWidthLayoutConstraint] setConstant：320.f];
   [自拍] layoutIfNeeded]
}];
 

I am using auto layout to position a custom progress bar (its simply a UIView with a background colour). Im not using a proper progress bar because I didnt want to have to fully customise it to my needs when a UIView will suffice.

Anyway I have told XCode to place the progress bar to the left, and a certain distance from the bottom. This positions it correctly but when I animate the width nothing happens. If I create a new UIVIew then animate that it works correctly. Are the constraints preventing this from animating? No constrains is placed upon the width at all

[UIView animateWithDuration:startingGameSeconds delay:0.0 options:UIViewAnimationOptionCurveLinear
                 animations:^(void) {
                     progressBar.frame = CGRectMake(progressBar.frame.origin.x,
                                                    progressBar.frame.origin.y,
                                                    320,
                                                    progressBar.frame.size.height);

                 }
                 completion:^(BOOL finished){
                 }];

解决方案

When you're using Auto Layout you shouldn't be using the setFrame: method anymore. When you want to animate the 'frame', you'll have to animate the constraints. I suppose your Auto Layout constraints are defined in Interface Builder. First, make sure you have a width layout constraint added to your progress bar. Next, create an IBOutlet for this width layout constraint. You can now animate the constraint like this:

[UIView animateWithDuration:1.f animations:^{
   [[self progressBarWidthLayoutConstraint] setConstant:320.f];
   [[self view] layoutIfNeeded];
}];

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