swift4 透明背景VC

1. 新建一个demo，在StoryBoard上创建三个VC，如下图：

image.png

1. 新建两个VC，SecondViewController，和ThirdViewController，分别与StoryBoard的VC相关联。
   以SecondViewController举例：

image.png

1. 该拖线的拖线，添加点击事件。

4.代码部分：

ViewController

// // ViewController.swift // ClearBgVC // // Created by iOS on 2018/10/16. // Copyright © 2018年 weiman. All rights reserved. // import UIKit class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() } /// 弹出透明背景的VC，present进来的 @IBAction func jumpToSecondVC(_ sender: Any) { let vc = SecondViewController.instance() vc.modalPresentationStyle = .custom vc.modalTransitionStyle = .crossDissolve present(vc, animated: true, completion: {}) } @IBAction func jumpToThirdVC(_ sender: Any) { DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.5) { [weak self] in if let image = self?.normalSnapshotImage() { let vc = ThirdViewController.instance(image: image) self?.navigationController?.pushViewController(vc, animated: true) } } } } extension ViewController { /// 普通截图 func normalSnapshotImage() -> UIImage? { UIGraphicsBeginImageContextWithOptions(view.frame.size, false, UIScreen.main.scale) if let context = UIGraphicsGetCurrentContext() { view.layer.render(in: context) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return image } return nil } } 

SecondViewController:

// // SecondViewController.swift // ClearBgVC // // Created by iOS on 2018/10/16. // Copyright © 2018年 weiman. All rights reserved. // import UIKit class SecondViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() setup() } private func setup() { } class func instance() -> SecondViewController { let storyBoard = UIStoryboard(name: "Main", bundle: nil) let vc = storyBoard.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController return vc } override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) { dismiss(animated: true) } } 

ThirdViewController:

// // ThirdViewController.swift // ClearBgVC // // Created by iOS on 2018/10/16. // Copyright © 2018年 weiman. All rights reserved. // import UIKit class ThirdViewController: UIViewController { @IBOutlet weak var bgImage: UIImageView! private var image: UIImage! override func viewDidLoad() { super.viewDidLoad() bgImage.image = image } class func instance(image: UIImage) -> ThirdViewController { let storyB = UIStoryboard.init(name: "Main", bundle: nil) let vc = storyB.instantiateViewController(withIdentifier: "ThirdViewController") as! ThirdViewController vc.image = image return vc } } 

效果：

QQ20181016-132820.gif