昨天用简书App的时候觉得这个View的弹出效果特别好，而且非常平滑，所以我就尝试写了一个，和简书App上的效果基本一致了:

下面开始讲解:

1.首先我们要知道这个页面有几个View？这个页面其实有四个View，self.view , 图中白色VC的View rootVC.view ,白色VC上的maskView maskView , 以及弹出的popView popView 。我们创建它们：

self.view.backgroundColor = [UIColor blackColor];

_popView = ({

UIView * popView = [[UIView alloc]initWithFrame:CGRectMake(0, [UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height /2.0)];

popView.backgroundColor = [UIColor grayColor];

//加个阴影

popView.layer.shadowColor = [UIColor blackColor].CGColor;

popView.layer.shadowOffset = CGSizeMake(0.5, 0.5);

popView.layer.shadowOpacity = 0.8;

popView.layer.shadowRadius = 5;

//关闭btn

UIButton * closeBtn = [UIButton buttonWithType:UIButtonTypeCustom];

closeBtn.frame = CGRectMake(15, 0, 50, 40);

[closeBtn setTitle:@"关闭" forState:UIControlStateNormal];

[closeBtn setTitleColor:[UIColor colorWithRed:217/255.0 green:110/255.0 blue:90/255.0 alpha:1] forState:UIControlStateNormal];

[closeBtn addTarget:self action:@selector(close) forControlEvents:UIControlEventTouchUpInside];

[popView addSubview:closeBtn];

popView;

});

//添加VC的View的方法

_rootVC.view.frame = self.view.bounds;

_rootVC.view.backgroundColor = [UIColor whiteColor];

_rootview = _rootVC.view;

[self addChildViewController:_rootVC];

[self.view addSubview:_rootview];

//rootVC上的maskView

_maskView = ({

UIView * maskView = [[UIView alloc]initWithFrame:self.view.bounds];

maskView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.5];

maskView.alpha = 0;

maskView;

});

[_rootview addSubview:_maskView];

2.然后要添加点击事件，这里为了方便我的弹出事件直接用的touchesBegan

- (void)show

{

[[UIApplication sharedApplication].windows[0] addSubview:_popView];

CGRect frame = _popView.frame;

frame.origin.y = self.view.frame.size.height/2.0;

[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{

[_rootview.layer setTransform:[self firstTransform]];

} completion:^(BOOL finished) {

[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{

[_rootview.layer setTransform:[self secondTransform]];

//显示maskView

[_maskView setAlpha:0.5f];

//popView上升

_popView.frame = frame;

} completion:^(BOOL finished) {

}];

}];

}

这里要注意一下的就是popview是添加到window上面的:[[UIApplication sharedApplication].windows[0] addSubview:_popView];

然后关键的layer形变方法来了

- (CATransform3D)firstTransform{

CATransform3D t1 = CATransform3DIdentity;

t1.m34 = 1.0/-900;

//带点缩小的效果

t1 = CATransform3DScale(t1, 0.95, 0.95, 1);

//绕x轴旋转

t1 = CATransform3DRotate(t1, 15.0 * M_PI/180.0, 1, 0, 0);

return t1;

}

- (CATransform3D)secondTransform{

CATransform3D t2 = CATransform3DIdentity;

t2.m34 = [self firstTransform].m34;

//向上移

t2 = CATransform3DTranslate(t2, 0, self.view.frame.size.height * (-0.08), 0);

//第二次缩小

t2 = CATransform3DScale(t2, 0.8, 0.8, 1);

return t2;

}

大家可以看到这，应该可以发现这里其实有两次形变

3.隐藏动画

- (void)close

{

_isShow = NO;

CGRect frame = _popView.frame;

frame.origin.y += self.view.frame.size.height/2.0;

[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{

//maskView隐藏

[_maskView setAlpha:0.f];

//popView下降

_popView.frame = frame;

//同时进行 感觉更丝滑

[_rootview.layer setTransform:[self firstTransform]];

} completion:^(BOOL finished) {

[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{

//变为初始值

[_rootview.layer setTransform:CATransform3DIdentity];

} completion:^(BOOL finished) {

//移除

[_popView removeFromSuperview];

}];

}];

}

最后，完整代码，已经封装好了，继承之后使用创建方法就行了

GitHub:Wzxhaha

https://github.com/Wzxhaha/WZXJianShuPopDemo