0

我有一个在屏幕上从右向左移动的对象:

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:7.8];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
 myImageview.layer.position = CGPointMake(20,  myImageView.layer.position.y);
[UIView commitAnimations];

我发现即使动画仍在播放,XCode 已经将图像的位置标记为其最终目的地,为了检测移动图像上的触摸,我需要使用presentationLayer:

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

    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self.view];

    if ([myImageview.layer.presentationLayer hitTest:touchPoint]) {
        NSLog(@"it's a hit!");
    }
}

这部分有效。现在,我希望图像在按下时向上移动。 我希望图像在继续横向移动的同时向上移动。 相反,这段代码不仅将图像向上移动,而且一直移动到左侧的最终目的地:

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

    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];   
    CGPoint touchPoint = [touch locationInView:self.view];

    if ([mouse.layer.presentationLayer hitTest:touchPoint]) {
        NSLog(@"it's a hit!");
        [UIView beginAnimations:nil context:nil];
        [UIView setAnimationDuration:0.5];
        [UIView setAnimationCurve:UIViewAnimationCurveLinear];
        myImageView.layer.position = CGPointMake( mouse.layer.position.x,  myImageView.layer.position.y - 40);
        [UIView commitAnimations];
    }
}

我希望图像在继续横向移动的同时向上移动。有谁知道实现这一目标的方法?

非常感谢!

4

1 回答 1

2

您是否尝试过设置动画选项UIViewAnimationOptionBeginFromCurrentState

(我说选项是因为它是 iOS 4 引入的基于块的动画方法中的一个选项。它也可用,就[UIView setAnimationBeginsFromCurrentState:YES]好像你还不能从已弃用的 UIView 类方法中切换出来一样。)

touchesBegan 变为(使用块动画):

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

    [super touchesBegan:touches withEvent:event];

    UITouch *touch = [touches anyObject];   
    CGPoint touchPoint = [touch locationInView:self.view];

    if ([mouse.layer.presentationLayer hitTest:touchPoint]) {
        NSLog(@"it's a hit!");
        [UIView animateWithDuration:0.5 delay:0.0 options:(UIViewAnimationOptionCurveLinear & UIViewAnimationOptionBeginFromCurrentState) animations:^{
            myImageView.layer.position = CGPointMake( myImageView.layer.position.x,  mouse.layer.position.y - 40);
        }completion:^(BOOL complete){
            //
        }];
    }
}

如果您使用它,您应该能够指定您想要的最终坐标xy坐标,并让动画从对象被触摸的点继续到该位置。

于 2012-10-03T03:40:38.420 回答