Question

我有一个奇怪的问题。我有一个自定义背景的UIButton和一个字符作为标题。我希望按钮能够通过动画变得更大。然而，动画有效，我再也看不到按钮的标题了。

这是我的代码：

UIButton *letterButton = [UIButton buttonWithType:UIButtonTypeCustom];
[letterButton.titleLabel setFont:[UIFont boldSystemFontOfSize:18.0f]];
[letterButton setTitle:[gameManager letterTextForIndex:curIndex] forState:UIControlStateNormal];
letterButton.frame = CGRectMake(curX + kLetterButtonSize / 2, curY + kLetterButtonSize / 2, 0.01f, 0.01f);
[letterButton addTarget:self action:@selector(pressedLetterButton:) forControlEvents:UIControlEventTouchUpInside];

UIImage *buttonImage = [[UIImage imageNamed:@"blueButton.png"]
                                resizableImageWithCapInsets:UIEdgeInsetsMake(18, 18, 18, 18)];
UIImage *buttonImageHighlight = [[UIImage imageNamed:@"blueButtonHighlight.png"]
                                         resizableImageWithCapInsets:UIEdgeInsetsMake(18, 18, 18, 18)];

[letterButton setBackgroundImage:buttonImage forState:UIControlStateNormal];
[letterButton setBackgroundImage:buttonImageHighlight forState:UIControlStateHighlighted];


[self.view addSubview:letterButton];

[UIButton animateWithDuration:0.20f delay:curIndex * 0.17f options:UIViewAnimationOptionTransitionNone animations:^
{
     letterButton.transform = CGAffineTransformMakeScale(kLetterButtonSize / 0.01f, kLetterButtonSize / 0.01f);
}
completion:^(BOOL finished)
{
     [letterButton setTitle:[gameManager letterTextForIndex:curIndex] forState:UIControlStateNormal];
 }];

正如您所看到的，我从一个非常小的按钮开始，并通过转换，随着时间的推移，我使按钮更大。我动态计算我的按钮的缩放因子是什么。

有人可以向我解释为什么按钮的标题不可见吗？

Answer 1

尝试相反的方法：为初始状态设置转换，为最终状态设置“un-transform”：

UIButton *letterButton = [UIButton buttonWithType:UIButtonTypeCustom];
[letterButton.titleLabel setFont:[UIFont boldSystemFontOfSize:18.0f]];
[letterButton setTitle:[gameManager letterTextForIndex:curIndex]
              forState:UIControlStateNormal];
letterButton.frame = CGRectMake(curX + kLetterButtonSize / 2, curY + kLetterButtonSize / 2, kLetterButtonSize, kLetterButtonSize);
letterButton.transform = CGAffineTransformMakeScale(0.01f/kLetterButtonSize, 0.01f/kLetterButtonSize);
[letterButton addTarget:self
                 action:@selector(pressedLetterButton:)
       forControlEvents:UIControlEventTouchUpInside];

 UIImage *buttonImage = [[UIImage imageNamed:@"blueButton.png"]
                         resizableImageWithCapInsets:UIEdgeInsetsMake(18, 18, 18, 18)];
 UIImage *buttonImageHighlight = [[UIImage imageNamed:@"blueButtonHighlight.png"]
                                  resizableImageWithCapInsets:UIEdgeInsetsMake(18, 18, 18, 18)];

[letterButton setBackgroundImage:buttonImage forState:UIControlStateNormal];
[letterButton setBackgroundImage:buttonImageHighlight forState:UIControlStateHighlighted];


[self.view addSubview:letterButton];

[UIButton animateWithDuration:0.20f delay:curIndex * 0.17f options:UIViewAnimationOptionTransitionNone animations:^
{
    letterButton.transform = CGAffineTransformIdentity;
}
completion:^(BOOL finished)
{
    [letterButton setTitle:[gameManager letterTextForIndex:curIndex] forState:UIControlStateNormal];
}];

在我的考试中，它对我有用。

通常，自CAAnimation出来以来，对我来说最好的结果一直是设置动画的最终状态，并使用逆变换作为开始状态。

UIButton的标题在转型后消失了

1 个答案: