Question

我想反复移动我的UIView从左到右，直到右侧边界没有到达视野。下面的代码重复运行，但只移动5个点，从起点开始重复，我想从上一个当前状态重复，+ 5再次移动。

CGPoint pos = mover.center;
pos.x=25;
int count = 25;
[UIView beginAnimations:nil context:NULL];
pos.x=count;
[UIView setAnimationDuration:0];

[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationRepeatCount:INFINITY];

//[UIView setAnimationRepeatAutoreverses:YES];


   // CGPoint pos = mover.center;

    //pos.x +=5;
    count = (pos.x+=5);
    mover.center = pos;

我希望看到物体在+5点间隔内移动。而且我是目标c和iphone的新手，所以请尽快帮助我。基本上我的任务是屏幕边框上的移动视图（从左到右，从上到下，从右到左，从下到上）意味着按顺序移动视图并反复通过模拟器屏幕的边框。我希望你的答案对我和其他新技术（iPhone）有帮助。非常感谢你。

Answer 1

要将视图从一个位置移动到另一个位置，我会将其框架设置在动画块内。这样的事情会对你有所帮助：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    // `customView` is a UIView defined in .h file
    customView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
    customView.backgroundColor = [UIColor redColor];

    [self.view addSubview:customView];

    [self rotateViewInSelfBoundary];
}

-(void)rotateViewInSelfBoundary
{
    CGRect screen = [[UIScreen mainScreen] bounds];

    // Top Left to top right
    [UIView animateWithDuration:3.0f
                     animations:^{
                         [customView setFrame:CGRectMake(screen.size.width - customView.frame.size.width, 0, 100, 100)];
                                 }
                     completion:^(BOOL finished)
    {
        // Top right to bottom right
        [UIView animateWithDuration:3.0f
                         animations:^{
                             [customView setFrame:CGRectMake(screen.size.width - customView.frame.size.width, screen.size.height - customView.frame.size.height, 100, 100)];
                         }
                         completion:^(BOOL finished)
         {
             // bottom right to bottom left
             [UIView animateWithDuration:3.0f
                              animations:^{
                                  [customView setFrame:CGRectMake(0, screen.size.height - customView.frame.size.height, 100, 100)];
                              }
                              completion:^(BOOL finished)
              {
                  // bottom left to top left
                  [UIView animateWithDuration:3.0f
                                   animations:^{
                                       [customView setFrame:CGRectMake(0, 0, 100, 100)];
                                   }
                                   completion:^(BOOL finished)
                   {
                       // call the same function again.
                       [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rotateViewInSelfBoundary) object:nil];
                       [self performSelector:@selector(rotateViewInSelfBoundary) withObject:nil afterDelay:0.0f];
                   }];
              }];
         }];
    }];
}

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enter image description here

Answer 2

使用 UIViewAnimationOptionBeginFromCurrentState 赞

 [UIView animateWithDuration:1.0f
                      delay:2.0f
                    options:UIViewAnimationOptionRepeat | UIViewAnimationOptionBeginFromCurrentState
                 animations:^{
//your animation                   
  }
               completion:nil];

Answer 3

如果要在正方形中移动视图，请定义它应在其间设置的四个CGPoint值，然后：

NSArray *values = @[[NSValue valueWithCGPoint:point0],
                    [NSValue valueWithCGPoint:point1],
                    [NSValue valueWithCGPoint:point2],
                    [NSValue valueWithCGPoint:point3],
                    [NSValue valueWithCGPoint:point0]];

CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
animation.values = values;
animation.duration = 5.0;
animation.repeatCount = HUGE_VALF;
[mover.layer addAnimation:animation forKey:@"moveAroundBorder"];

这将处理视图的所有移动，而无需您进一步干预。

如果您想使用基于iOS 7块的关键帧动画，那么它将是：

[UIView animateWithDuration:5.0 delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
    [UIView animateKeyframesWithDuration:5.0 delay:0.0 options:UIViewKeyframeAnimationOptionRepeat | UIViewKeyframeAnimationOptionCalculationModeLinear animations:^{
        [UIView addKeyframeWithRelativeStartTime:0.00 relativeDuration:0.25 animations:^{
            mover.center = point0;
        }];
        [UIView addKeyframeWithRelativeStartTime:0.25 relativeDuration:0.25 animations:^{
            mover.center = point1;
        }];
        [UIView addKeyframeWithRelativeStartTime:0.50 relativeDuration:0.25 animations:^{
            mover.center = point2;
        }];
        [UIView addKeyframeWithRelativeStartTime:0.75 relativeDuration:0.25 animations:^{
            mover.center = point3;
        }];
    } completion:nil];
} completion:nil];

请注意animateKeyframesWithDuration中animateWithDuration的好奇嵌套。那是因为UIViewKeyframeAnimationOptionCalculationModeLinear奇怪地没有停止“缓入/缓出”行为，所以你必须在外部动画块上指定UIViewAnimationOptionCurveLinear。

如何从当前状态重复动画而不是从起始状态？

3 个答案:

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