好久沒更新自己的簡(jiǎn)書了,悲哀呀...
先來個(gè)效果圖吧

transformAimationGif.gif

1. 先拽兩個(gè)控制器, 藍(lán)色關(guān)聯(lián)PushViewController, 淺黃色關(guān)聯(lián)PopViewController,如圖:

圖1.png

2. 關(guān)聯(lián)屬性于Push

圖2.png

3. 做過自定義轉(zhuǎn)場(chǎng)動(dòng)畫的同學(xué)們應(yīng)該都曉得必須遵守<UIViewControllerAnimatedTransitioning>協(xié)議,那么這里就創(chuàng)建一個(gè)類(CustomPushTransition)專門來實(shí)現(xiàn)此轉(zhuǎn)場(chǎng)效果.在.m必須實(shí)現(xiàn)這兩個(gè)方法:

   - (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext;
   - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
   

4. 代碼如下, 大致思想:創(chuàng)建兩個(gè)圓(利用貝爾曲線),一個(gè)是與push按鈕的size, 另一個(gè)是有足夠覆蓋屏幕的半徑,最后的動(dòng)畫是由這兩個(gè)的path來完成.

   @property (nonatomic, strong) id<UIViewControllerContextTransitioning>customTransitionContext;
   
   - (NSTimeInterval)transitionDuration:(nullable id <UIViewControllerContextTransitioning>)transitionContext{
       return .5f;
     }
   
   - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext{
         self.
         PushViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
         PopViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
   
         //獲取push控制器中按鈕. 
         UIButton *button = fromVC.push;
         //獲取容器
         UIView *containerView = [transitionContext containerView];
         //添加視圖
         [containerView addSubView:fromVC.view];
         [containerView addSubView:toVC.view];
         
         //繪制小圓, Oval:橢圓形
         UIBezierPath *startBP = [UIBezierPath bezierPathWithOvalInRect:button.frame];
         //繪制大圓, 需先確定半徑,其實(shí)這里用到勾股定理,很好理解的,如圖3:
         CGFloat horizontalSide_X = button.center.x;
         CGFloat verticalSide_Y = CGRectGetMaxY(toVC.view.bounds) - button.center.y;
         CGFloat radius = sqrt( (horizontalSide_X * horizontalSide_X) + (verticalSide_Y * verticalSide_Y) );
         /*
        CGRect CGRectInset (
          CGRect rect,
          CGFloat dx,
          CGFloat dy
        ); 解釋: 該結(jié)構(gòu)體是以rect的中點(diǎn)為中心,插入一個(gè)以dx,dy為參考的放大或縮小的矩形; 正表示縮小,負(fù)表示放大. 
           所以繪制大圓是以小圓(button.frame)為中心點(diǎn),插入一個(gè)radius尺寸的放大的圓
         */
         UIBezierPath *finalBP = [UIBezierPath bezierPathWithOvalInRect:CGRectInset(button.frame, -radius, -radius)];
         CAShapeLayer *maskLayer = [CAShapeLayer layer];
         maskLayer.path = finalBP.CGPath;
         
         //設(shè)置目標(biāo)控制器的mask
         toVC.view.layer.mask = maskLayer;
   
         //執(zhí)行動(dòng)畫
         CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"];
         animation.fromValue = (__bridge id _Nullable)(startBP.CGPath);
         animation.toValue = (__bridge id _Nullable)(finalBP.CGPath);
         animation.during = [self transitionDuration:transitionContext];
         animation.timingFuncion = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
         animation.delegate = self;
         [maskLayer addAnimation:maskLayerAnimation forKey:@"path"];
         }
   

   pragma mark - CABasicAnimation

   • (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
     //告訴系統(tǒng)轉(zhuǎn)場(chǎng)動(dòng)畫完成
     [self.customTransitionContext completeTransition:![self.customTransitionContext transitionWasCancelled]];
     //清除相應(yīng)控制器視圖的mask
     [self.customTransitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view.layer.mask = nil;
     [self.customTransitionContext viewControllerForKey:UITransitionContextToViewControllerKey].view.layer.mask = nil;
     }

     
     
     圖3.png

5. push的自定義轉(zhuǎn)場(chǎng)基本完成了,現(xiàn)在回到PushViewController上, 控制器須遵守<UINavigationControllerDelegate>協(xié)議, 所以self.navigationCtroller.delegate = self; //注意設(shè)置導(dǎo)航控制器的代理須寫在viewWillAppear中或是viewDidAppear.實(shí)現(xiàn)導(dǎo)航控制器的代理:

#pragma mark - UINavigationControllerDelegate
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController animationControllerForOperation:(UINavigationControllerOperation)operation fromViewController:(UIViewController *)fromVC toViewController:(UIViewController *)toVC{

        if (operation == UINavigationControllerOperationPush) {
        return self.pushAnimation;
    }
    return nil;
}

#pragma mark - 懶加載
- (CustomPushTransition *)pushAnimation{
     if (!_pushAnimation) {
     _pushAnimation = [[CustomPushTransition alloc] init];
   }
     return _pushAnimation;
}