多个 UIView 的动画与 UIBezierPath

Question

我有以下屏幕：

当我点击获取更多按钮时，它会添加新的圆形按钮。我在UIView 上添加了平移手势，其中添加了所有圆形按钮，然后将仅从圆形按钮绘制UIBezierPath。到目前为止，一切正常。

现在，我想要以下内容：

1. 我有一个名为 playGroundView 的父 UIView，它包含所有圆形按钮。这将为所有这些按钮绘制一个贝塞尔路径。
2. 为所有按钮绘制 Bezier 路径后，我单击“移动按钮”立即为所有圆形按钮设置动画。
3. 一旦所有 Button 移动到 Bezier Path 的终点，我就可以再次绘制 Bezier Path（为 Rounded Button 添加更多步骤）连接到相同按钮的相同路径。
4. 此后，Final Move 按钮将立即为同一个按钮设置动画。

PlayGround UIView 子类参考以下代码：

@interface PlayGroundView : UIView
@property (nonatomic, weak) PlayGroundViewController *playViewController;
@end

#import "PlayGroundView.h"
#import "RoundedButton.h"
#import "PlayGroundViewController.h"

@interface PlayGroundView () {
    UIBezierPath *path;
    BOOL isDrawPointInside;
}

@end

@implementation PlayGroundView

#pragma mark - View Methods -
- (id)initWithCoder:(NSCoder *)aDecoder {
    if (self = [super initWithCoder:aDecoder])
        [self commonInit];
    return self;
}

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame])
        [self commonInit];
    return self;
}

- (void)drawRect:(CGRect)rect {
    [[UIColor redColor] setStroke];
    [path stroke];
}

#pragma mark - Action Methods -
- (void)pan:(UIPanGestureRecognizer *)pan {
    CGPoint currentPoint = [pan locationInView:self];
    //    NSLog(@"currentPoint: %@", NSStringFromCGPoint(currentPoint));
    if (pan.state == UIGestureRecognizerStateBegan) {
        NSMutableArray *buttonAry = [NSMutableArray array];
        buttonAry = self.playViewController.rBtnOpponentPlayerList;
        [buttonAry addObjectsFromArray:self.playViewController.rBtnPlayerList];
        for (int i=0; i<buttonAry.count; i++) {
            UIButton *btn = [buttonAry objectAtIndex:i];
            CGRect nearByRect = CGRectMake(btn.frame.origin.x - 20, btn.frame.origin.y - 20, btn.frame.size.width + 40, btn.frame.size.height + 40);
            if (CGRectContainsPoint(nearByRect, currentPoint)) {
                isDrawPointInside = YES;
                [path moveToPoint:btn.center];
                //                NSLog(@"point is inside....");
            }
        }
    }
    if (pan.state == UIGestureRecognizerStateChanged) {
        if (isDrawPointInside) {
            [path addLineToPoint:currentPoint];
            [self setNeedsDisplay];
        }
    }
    
    if (pan.state == UIGestureRecognizerStateEnded) {
        isDrawPointInside = NO;
        //        NSLog(@"pan ended");
    }
}

#pragma mark - Helper Methods -
- (void)commonInit {
    path = [UIBezierPath bezierPath];
    path.lineWidth = 3.0;
    
    // Capture touches
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
    pan.maximumNumberOfTouches = pan.minimumNumberOfTouches = 1;
    [self addGestureRecognizer:pan];
    
    // Erase with long press
    [self addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(erase)]];
}

- (void)erase {
    path = [UIBezierPath bezierPath];
    path.lineWidth = 3.0;

    [self setNeedsDisplay];
}

@end

我仍然无法管理所有圆形按钮状态。告诉我在移动时管理圆形按钮所有步骤的最佳方法。

我参考过：http://nachbaur.com/blog/core-animation-part-4

我的完整演示代码位于：https://www.dropbox.com/s/f0ri0bff8ioxtpz/FreeHandDrawingDemo%202.zip?dl=0

Answer 1

我假设，当你说“管理所有圆形按钮状态”时，你的意思是你想知道视图已经开始动画化，比如viewHasMovedABitAutomatically 回调:) 如果是这样的话，据我所知，CA 框架中没有实现的方法可以做到这一点。但是，看看这个问题：Core animation progress callback 这是一种看起来很不错的解决方法，也许你可以从这里开始做一些事情。

哦，还有一件事。我看到您正在使用平移手势识别器。我刚刚浏览了你的代码和tarmes'（另一个线程中的那个人;））但我认为他正在使用drawInContext来检查正在绘制的图层。如果您的视图是可拖动的，这也可能会触发，因此，如果是这种情况，请考虑在 pan 方法上使用一些 viewIsBeingDragged 标志，并在回调中检查它。

编辑：抱歉，这似乎与您的实际问题无关。我了解您的意思是控制动画速度，以便它们都相应地移动。让我们详细说明一下。

据我所知，没有动画“步骤”之类的东西。使图像向左移动 20 像素的动画并不一定意味着图像将被重绘 20 次。图像将根据需要被渲染多次，因此我们不能依赖 render 方法来计算它。据我所知，控制动画速度的唯一方法是通过animateWithDuration: 的duration 参数。而且你不知道持续时间，你想让速度保持恒定，所以持续时间是任意的。

基本物理学：持续时间等于距离除以速度，所以如果我们有需要覆盖的距离，我们可以轻松计算动画持续时间。一开始我以为 UIBezierPath 可能有一个方法或一个属性来计算总长度，但我错了。但是，在这个线程Get CGPath total length 中有一个代码可以通过数值积分来计算它，你应该测试它是否有效。有了它之后，就可以做这样的事情了（我没测试，我只是输入伪代码）

#define SPEED_CALIBRATION 30.0 // or whatever

-(void)animateView:(UIView*)view withBezierPath:(UIBezierPath*)path {
    CGFloat distance = [self getBezierPathDistance:path];
    CGFloat duration = distance / SPEED_CALIBRATION;
    [self animateView:view withDuration:duration andBezierPath:path];
}

类似的东西。 getBezierPathDistance 是上面线程中的方法，假设它有效，animateView:withDuration:andBezierPath: 是您使用 CA 文档执行非线性动画的方法（我不太记得所有细节，但我记得它是相当长的代码块；））。

如果答案有点含糊，我很抱歉，希望对您有所帮助！

Answer 2

为了实现的东西，我使用了UIBezierPath+Points 类。除此之外，在我的代码中使用了以下类和逻辑：

在 PlayGroundView 中，我在 drawRect 方法中编辑了代码，其余代码相同：

- (void)drawRect:(CGRect)rect {
    [[UIColor redColor] setStroke];
    for (int i=0; i<[self subviews].count; i++) {
        RoundButton *tmpPlayerButton = [self.subviews objectAtIndex:i];
        for (UIBezierPath *bezierPath in tmpPlayerButton.allPathsOfPlayer) {
            [bezierPath strokeWithBlendMode:kCGBlendModeNormal alpha:1.0];
        }
    }
    [path stroke];
}

在我的 ViewController 类中，在 Get More Buttons 下面的代码中：

- (IBAction)getBallPressed:(id)sender {
    [self moveBalls];

//    self.playView.viewController = self;

    int xPos = self.view.frame.size.width-30;
    int yPos = self.view.frame.size.height-30;
    int btnXPos = arc4random_uniform(xPos);
    int btnYPos = arc4random_uniform(yPos);

    RoundButton *newButton = [[RoundButton alloc] initWithFrame:CGRectMake(btnXPos, btnYPos, 30, 30)];
    [newButton setBackgroundColor:[UIColor redColor]];
    newButton.layer.cornerRadius = newButton.frame.size.height/2;
    [newButton setTitle:[self randomStringWithLength:1] forState:UIControlStateNormal];

    UILongPressGestureRecognizer *longGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longGestureRecognized:)];
    [newButton addGestureRecognizer:longGesture];

    [self.playView.playerArray addObject:newButton];
    [self.playView addSubview:newButton];
}

- (void)moveBalls {
    for (int i=0; i<[self.playView subviews].count; i++) {
        RoundButton *playerButton = [self.playView.subviews objectAtIndex:i];
        if (playerButton.isEditPath) {
            id point = [[[playerButton.allPathsOfPlayer lastObject] points] lastObject];
            CGPoint lastPoint = [point CGPointValue];
            NSLog(@"lastPoint: %@", NSStringFromCGPoint(lastPoint));
            [playerButton setCenter:lastPoint];
        }
    }
}

在移动按钮中，下面的代码允许我同时移动所有圆形按钮，这是我的确切要求：

- (void)playAnimation {
    for (int i=0; i<self.playView.subviews.count; i++) {
        //Prepare the animation - we use keyframe animation for animations of this complexity
        CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
        //Set some variables on the animation
        pathAnimation.calculationMode = kCAAnimationPaced;

        //We want the animation to persist - not so important in this case - but kept for clarity
        //If we animated something from left to right - and we wanted it to stay in the new position,
        //then we would need these parameters
        pathAnimation.fillMode = kCAFillModeForwards;
        pathAnimation.removedOnCompletion = NO;
        pathAnimation.duration = 2.0;
        pathAnimation.repeatCount = 0;

        RoundButton *tmpRoundButton;
        UIBezierPath *path;

        tmpRoundButton = [self.playView.subviews objectAtIndex:i];

        for (int j=0; j<tmpRoundButton.allPathsOfPlayer.count; j++) {
            if (path)
                [path appendPath:[tmpRoundButton.allPathsOfPlayer objectAtIndex:j]];
            else
                path = [tmpRoundButton.allPathsOfPlayer objectAtIndex:j];

            //Now we have the path, we tell the animation we want to use this path - then we release the path
            pathAnimation.path = [path CGPath];
            [tmpRoundButton.layer addAnimation:pathAnimation forKey:@"moveTheSquare"];
        }
        [path moveToPoint:[[[path points] firstObject] CGPointValue]];
    }
    [self.playView setNeedsDisplay];
}

Answer 3

let playerController = AVPlayerViewController()
    playerController.delegate = self
    player = AVPlayer(url: url as URL)
    playerController.player = player
    self.addChildViewController(playerController)
    self.videoview.addSubview(playerController.view)
    playerController.view.frame = self.videoview.bounds
    player.play()