Bottom Navigation Drawer doesn't show up (Swift)

Question

I currently working on an iOS app and I want to use a bottom navigation drawer from material-io. So I did it like it is explained in the examples on the site. But when I present the navigation Drawer the ViewController only gets a bit darker and the contentView of the drawer isn't shown.

Here is my Code:

import Foundation
import UIKit
import MaterialComponents

class CreateSubjectView: UIViewController, UITextFieldDelegate {
    ...
    override func viewDidLoad() {
        ...
        let bottomDrawerViewController = MDCBottomDrawerViewController()
        self.modalPresentationStyle = .popover
        let newViewController = self.storyboard?.instantiateViewController(withIdentifier: "TEST")
        bottomDrawerViewController.contentViewController = newViewController

        present(bottomDrawerViewController, animated: true, completion: nil)    
        ...
    }
    ...
}

this problem occurs even if the drawer is activated with a button well after viewDidAppear. — zakdances
– zakdances, Commented Jun 25, 2020 at 7:02

Asperi · Accepted Answer · 2020-06-29 06:12:26Z

3

Your view controller to be shown in drawer must have specified preferred content size.

Here is a demo of minimal controller. (Note: modalPresentationStyle = .popover has no effect on MDCBottomDrawerViewController)

Tested with Xcode 12

  // button action in parent controller
  @objc private func presentNavigationDrawer() {
    let bottomDrawerViewController = MDCBottomDrawerViewController()
    bottomDrawerViewController.contentViewController = DemoViewController()
    present(bottomDrawerViewController, animated: true, completion: nil)
  }
}

class DemoViewController: UIViewController {

    override func loadView() {
        super.loadView()
        let view = UIView()
        view.backgroundColor = .red
        self.view = view
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

        // specify your content preferred height explicitly
        self.preferredContentSize = CGSize(width: 0, height: 400)     // required !!
    }

    @available(iOS 11.0, *)
    override func viewSafeAreaInsetsDidChange() {
        super.viewSafeAreaInsetsDidChange()

        // specify your content preferred height explicitly
        self.preferredContentSize = CGSize(width: 0, height: 400)     // required !!
    }
}

answered Jun 29, 2020 at 6:12

Asperi

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4 Comments

Asperi Over a year ago

@Chamitha - see solution

Asperi Over a year ago

@kristofferarl - see solution

Asperi Over a year ago

@jeffrey-liu - see solution

Lane Faison Over a year ago

Thank you. This is the only example solution I could find on the entire web. Do you know how to get the drawer to slide in from the side instead of the bottom, like it appears to in their documentation (material.io/components/navigation-drawer)? Or is this just a bottom-up component?

Shehata Gamal · Accepted Answer · 2019-01-27 12:27:40Z

1

Move this to viewWillAppear/ viewDidAppear once as it's too early for viewDidLoad to present a vc

class CreateSubjectView: UIViewController, UITextFieldDelegate {

    let bottomDrawerViewController = MDCBottomDrawerViewController()
    var once = true
    override func viewDidLoad() {
      super.viewDidLoad()

    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        if once {

            let newViewController = self.storyboard?.instantiateViewController(withIdentifier: "TEST")
            bottomDrawerViewController.contentViewController = newViewController
            present(bottomDrawerViewController, animated: true, completion: nil)

            once  = false
        }
    }

}

edited Jan 27, 2019 at 12:27

answered Jan 27, 2019 at 12:13

Shehata Gamal

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3 Comments

Jeffrey Liu Over a year ago

See something flashing to the right, but nothing really shows.

KristofferArl Over a year ago

Any update on this? Struggling with the same issue.

Chamitha Over a year ago

Anyone resolve this? I'm presenting the drawer on a button click therefore it is after viewDidLoad and viewWillAppear

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