iOS翻译和缩放动画

Question

我正在研究UIButton动画，其中：

UIButton设置在屏幕的底部中央，并缩放为小尺寸

_menuBtn.transform = CGAffineTransformMakeScale(0.1f, 0.1f);

当应用程序启动时，它应该移动到屏幕的左下方，因为它会缩放或增长到原始大小。

- (void)viewDidLoad
{
    [super viewDidLoad];

    _menuBtn.frame = CGRectMake(160, 513, 30, 30); 
    _menuBtn.superview.frame = CGRectMake(160, 513, 30, 30);

    _menuBtn.transform = CGAffineTransformMakeScale(0.1f, 0.1f);
    NSLog(@"_menuBtn: %@ ; _menuBtn.superview: %@", _menuBtn, _menuBtn.superview);
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:5];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    CGAffineTransform scaleTrans  = CGAffineTransformMakeScale(1.0f, 1.0f);
    CGAffineTransform lefttorightTrans  = CGAffineTransformMakeTranslation(-200.0f,0.0f);
    _menuBtn.transform = CGAffineTransformConcat(scaleTrans, lefttorightTrans);
    [UIView commitAnimations];

}

问题

当动画开始时，按钮开始从屏幕的右下方开始移动而不是在它应该是的底部中心。有什么帮助吗？

记录结果

NSLog(@"%@", _myBtn);

2013-08-14 09:22:38.913 GJCoolNavi[339:c07] <UIButton: 0x813ea30; frame = (0 0; 0 0); opaque = NO; autoresize = TM+BM; layer = <CALayer: 0x813eaf0>>

那是在做动画之前......动画之后的结果是：

2013-08-14 09:30:25.719 GJCoolNavi[612:c07] <UIButton: 0x71206d0; frame = (160 294; 0 0); opaque = NO; autoresize = TM+BM; animations = { transform=<CABasicAnimation: 0x7536a80>; position=<CABasicAnimation: 0x7537dd0>; }; layer = <CALayer: 0x7120790>>

Answer 1

你为什么不这样做......

_menuBtn.transform = CGAffineTransformMakeScale(0.1, 0.1);

[UIView animateWithDuration:5.0
options:UIViewAnimationOptionCurveEaseOut
animations:^(){
    _menuBtn.transform = CGAffineTransformMakeScale(1.0, 1.0);
    _menuBtn.center = self.view.center;
}
completion:nil];

我会避免使用变换来移动东西。改为改变框架。

修改

- (void)viewDidLoad
{
    [super viewDidLoad];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    // for convenience I'm pulling these values out in to variables.
    float buttonWidth = _menuBtn.frame.size.width;
    float buttonHeight = _menuBtn.frame.size.height;
    float viewWidth = self.view.frame.size.width;
    float viewHeight = self.view.frame.size.height;

    // set the button frame to be the bottom center
    // note you shouldn't have to do this as Interface Builder should already place it there.
    // place the button in the horizontal center and 20 points from the bottom of the view.
    _menuBtn.frame = CGRectMake((viewWidth - buttonWidth) * 0.5, viewHeight - buttonHeight - 20, buttonWidth, buttonHeight);

    // scale the button down before the animation...
    _menuBtn.transform = CGAffineTransformMakeScale(0.1, 0.1);

    // now animate the view...
    [UIView animateWithDuration:5.0
                          delay:0.0
                        options:UIViewAnimationOptionCurveEaseOut
                     animations:^{
                         _menuBtn.transform = CGAffineTransformIdentity;
                         _menuBtn.frame = CGRectMake(viewWidth - buttonWidth - 20, viewHeight - buttonHeight - 20, buttonWidth, buttonHeight);
                     }
                     completion:nil];
}

试试这个，让我知道会发生什么。

Answer 2

这解决了类似的问题。

应用（UIButton）.imageView动画。

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDelegate:self];
[UIView setAnimationDuration:5];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
CGAffineTransform scaleTrans  = CGAffineTransformMakeScale(1.0f, 1.0f);
CGAffineTransform lefttorightTrans  = CGAffineTransformMakeTranslation(-200.0f,0.0f);
_menuBtn.imageView.transform = CGAffineTransformConcat(scaleTrans, lefttorightTrans);
[UIView commitAnimations];

Answer 3

此现象表明您的按钮的原始帧错误，可能是因为其自动调整大小。在开始动画之前，尝试将其框架设置到底部中心。

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    _menuBtn.superview.frame = CGRectMake(0, 513, 320, 30); // This is a quick and dirty solution to make sure your button's superview is in the right place. You probably don't want to do this and are more likely to review your view hierarchy.
    _menuBtn.frame = CGRectMake(145, 0, 30, 30); // Set the frame to the bottom center, please ensure that _menuBtn's transform hasn't been changed before this step
    _menuBtn.transform = CGAffineTransformMakeScale(0.1f, 0.1f);
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:5];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
    CGAffineTransform scaleTrans  = CGAffineTransformMakeScale(1.0f, 1.0f);
    CGAffineTransform lefttorightTrans  = CGAffineTransformMakeTranslation(-200.0f,0.0f);
    _menuBtn.transform = CGAffineTransformConcat(scaleTrans, lefttorightTrans);
    [UIView commitAnimations];
}

Answer 4

我已经使用了你的代码，它完全从底部中心移动到左下角。可能你的超级视图不正确。请检查。