如何使用移动标签正确创建动画并在动画进行时禁用任何 UI 交互

Question

我需要在 iOS 的 Objective-C 中创建带有移动标签的动画。当用户点击某个按钮时，动画应该会出现。我还需要在动画进行时禁用任何 UI 交互。这就是我为实现这种行为所做的：

1.在视图控制器的viewDidLoad方法中创建UILabel对象，将所有需要的字段设置为合适的值并隐藏：

plusScoreLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 50.0f, 50.0f)];
plusScoreLabel.text = @"+10";
plusScoreLabel.textColor = [UIColor colorWithRed:12.0/255.0 green:144.0/255.0 blue:51.0/255.0 alpha:1.0];
plusScoreLabel.hidden = YES;
plusScoreLabel.textAlignment = NSTextAlignmentCenter;
[self.view addSubview:plusScoreLabel];

uiInteractionsDisabled = NO;

2.然后我在按钮按下的动作上调用 animateWithDuration:animation:completion 方法，如下所示：

uiInteractionsDisabled = YES;
[plusScoreLabel setCenter:CGPointMake(buttonToChoose.center.x, buttonToChoose.center.y)];
plusScoreLabel.hidden = NO;
[UIView animateWithDuration:0.5f animations:^{
        plusScoreLabel.center = CGPointMake(buttonToChoose.center.x, buttonToChoose.center.y - 50.0f);
    } completion:^(BOOL finished) {
        plusScoreLabel.hidden = YES;
    }];

3.在每个 IBAction 方法中添加以下检查：

if (uiInteractionsDisabled == YES) {
    return;
}

这个方法有问题吗？也许有更好的方法来实现这种行为？

提前致谢。

Answer 1

您的解决方案没有任何问题。 如果你想要一些特别的东西，你可以继承 CABasicAnimation 并覆盖其中的两个方法：

/* Called when the animation begins its active duration. */

- (void)animationDidStart:(CAAnimation *)anim;

/* Called when the animation either completes its active duration or
 * is removed from the object it is attached to (i.e. the layer). 'flag'
 * is true if the animation reached the end of its active duration
 * without being removed. */

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag;

此外，您还可以向子类添加两个块属性：

@property (nonatomic, copy) void  (^startBlock)(void) ;
@property (nonatomic, copy) void  (^finishBlock)(void) ;

并在覆盖的方法中执行块：

- (void)animationDidStart:(CAAnimation *)anim{
    if (_startBlock){
        _startBlock();
    }
}
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
    if (_finishBlock){
        _finishBlock();
    }
}

之后，您可以像这样使用自定义动画对象：

    MyCustomAnimation* anim = [MyCustomAnimation animationWithKeyPath:@"position"];
    anim.startBlock = ^{uiInteractionsDisabled = YES;};
    anim.finishBlock = ^{uiInteractionsDisabled = NO;};
    [anim setFromValue:[NSValue valueWithCGPoint:CGPointMake(buttonToChoose.center.x, buttonToChoose.center.y)]];
    [anim setToValue:[NSValue valueWithCGPoint:CGPointMake(buttonToChoose.center.x, buttonToChoose.center.y - 50.0f)]];
    [anim setDuration:0.5];
    [plusScoreLabel.layer addAnimation:anim forKey:@"translationAnimation"];

我希望你学到了一些新东西:)