动画UIButton状态变化

Question

我正在使用带有正常和突出显示状态图像的UIButton。它们按预期工作但我希望有一些渐变/合并过渡，而不仅仅是突然交换。

我该怎么做？

Answer 1

这可以使用UIView的过渡动画来完成。 isHighlighted属性不可动画无关紧要，因为它会转换整个视图。

Swift 3

UIView.transition(with: button,
                  duration: 4.0,
                  options: .transitionCrossDissolve,
                  animations: { button.isHighlighted = true },
                  completion: nil)

目标C

[UIView transitionWithView:button
                  duration:4.0
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{ button.highlighted = YES; }
                completion:nil];

Answer 2

为了实现这一点，我扩展了UIButton。使用以下代码添加了一个名为hilightedImage的新属性：

- (void)setHilightImage:(UIImageView *)_hilightImage
{
    if (hilightImage != _hilightImage) {
        [hilightImage release];
        hilightImage = [_hilightImage retain];
    }
    [hilightImage setAlpha:0];
    [self addSubview:hilightImage];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.14];
    if(hilightImage){
        [hilightImage setAlpha:1];
    }
    [UIView commitAnimations];
    [super touchesBegan:touches withEvent:event];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    self.highlighted = FALSE;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.14];
    if(hilightImage){
        [hilightImage setAlpha:0];
    }

    [UIView commitAnimations];
    [super touchesEnded:touches withEvent:event];
}

Answer 3

这是一个自包含的解决方案，它还支持布尔animated标志。

- (void)setEnabled:(BOOL)enabled animated:(BOOL)animated
{
  if (_button.enabled == enabled) {
    return;
  }

  void (^transitionBlock)(void) = ^void(void) {
    _button.enabled = enabled;
  };

  if (animated) {
    [UIView transitionWithView:_button
                      duration:0.15
                       options:UIViewAnimationOptionTransitionCrossDissolve
                    animations:^{
                      transitionBlock();
                    }
                    completion:nil];
  } else {
    transitionBlock();
  }
}

Answer 4

@marián-Černý以 Swift 回答：

UIView.transitionWithView(button, 
                          duration: 4.0, 
                          options: .TransitionCrossDissolve, 
                          animations: { button.highlighted = true },
                          completion: nil)

Answer 5

UIButton继承自UIView

然后你得到它的观点并致电beginAnimations:context:

然后从那里得到所有合适的setAnimation方法。

UIView类的以下属性是可动画的：

• @property frame
• @property bounds
• @property centre
• @property transform
• @property alpha
• @property backgroundColor
• @property contentStretch

参考：UIView Class Reference

Answer 6

使用 CustomButton 而不是 UIButton 并覆盖 isHighlighted 属性对我有用；

class KeypadButton: UIButton {
    var highlightDuration: TimeInterval = 0.25
    
    override var isHighlighted: Bool {
        didSet {
            if oldValue == false && isHighlighted {
                highlight()
            } else if oldValue == true && !isHighlighted {
                unHighlight()
            }
        }
    }

    func highlight() {
        animateBackground(to: highlightedBackgroundColor, duration: highlightDuration)
    }

    func unHighlight() {
        animateBackground(to: normalBackgroundColor, duration: highlightDuration)
    }
    
    private func animateBackground(to color: UIColor?, duration: TimeInterval) {
        guard let color = color else { return }
        UIView.animate(withDuration: highlightDuration) {
            self.backgroundColor = color
        }
    }
}