iPhone UIButton 翻转和展开

Question

我正在尝试制作一个简单的按钮来更改大小并在后续点击时展开然后缩小。

它有点工作，翻转后的最后一个按钮看起来是正确的 - 它是圆形的并且大小不同。问题是在过渡期间，我得到了这种奇怪的非圆形效果。请参阅此链接以了解此问题 --> http://screencast.com/t/rJaSJ0nGq。

如何使过渡平滑且始终看起来是圆形的？我不想要截屏视频中出现的圆角矩形外观。

这是我的按钮点击方法：

// Handle when a user presses the button
- (IBAction)bubblePressed:(id)sender {

    // Expand the bubble if it's pressed or de-expand it if
    // already expanded
    if ( buttonResized ) {

        CGRect tempFrame=self.expandMe.frame;
        tempFrame.size.width=100;//change acco. how much you want to expand
        tempFrame.size.height=100;
        [UIView beginAnimations:@"" context:nil];
        [UIView setAnimationDuration:BUTTON_FLIP_TIME];
        self.expandMe.frame=tempFrame;

        // Round the buttons
        self.expandMe.clipsToBounds = YES;
        self.expandMe.layer.cornerRadius = self.expandMe.frame.size.width / 2;//half of the width
        self.expandMe.layer.borderColor=[UIColor clearColor].CGColor;
        self.expandMe.layer.borderWidth=2.0f;

        // Flip the button
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.expandMe cache:YES];

        [UIView commitAnimations];

    }
    else {

        CGRect tempFrame=self.expandMe.frame;
        tempFrame.size.width=200;//change acco. how much you want to expand
        tempFrame.size.height=200;
        [UIView beginAnimations:@"" context:nil];
        [UIView setAnimationDuration:BUTTON_FLIP_TIME];
        self.expandMe.frame=tempFrame;

        // Round the buttons
        self.expandMe.clipsToBounds = YES;
        self.expandMe.layer.cornerRadius = self.expandMe.frame.size.width / 2;//half of the width
        self.expandMe.layer.borderColor=[UIColor clearColor].CGColor;
        self.expandMe.layer.borderWidth=2.0f;

        // Flip the button
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.expandMe cache:YES];

        [UIView commitAnimations];

    }

    // Flip the variable that tracks flipping
    buttonResized = !buttonResized;

}

Answer 1

最后我找到了这个 --> https://github.com/ole/OBShapedButton。这是一门很棒的课程，并且获得了麻省理工学院的许可。