Switching ViewControllers with UISegmentedControl

问题:

I am trying something very simple but somehow I can't get it to work. All I try to do is switching between 2 View Controllers using an UISegmentedControl as you can see it for example in the App Store application in the Highlights tab.

I am using iOS5 and Storyboards.

Here's my Storyboad line up:

So I have a root View Controller and two UITableViews - This 2 TableViews I want to switch.

Here's how the implementation file looks like

#import "SegmentedLocationViewController.h"
#import "PastEventsLocationViewController.h"
#import "FutureEventsLocationViewController.h"

@interface SegmentedLocationViewController()
@property (weak, nonatomic) IBOutlet UISegmentedControl *segmentedControl;
@property (strong, nonatomic) NSArray *viewControllers;
@end


@implementation SegmentedLocationViewController

@synthesize segmentedControl = _segmentedControl;
@synthesize viewControllers = _viewControllers;

- (IBAction)indexDidChangeForSegmentedControl:(UISegmentedControl*)segmentedControl
{
    NSLog(@"index: %d", segmentedControl.selectedSegmentIndex);
}

- (void)setupViewControllers
{
    PastEventsLocationViewController *pastEventsLocationViewController = [[PastEventsLocationViewController alloc] initWithStyle:UITableViewStylePlain];
    FutureEventsLocationViewController *futureEventsLocationViewController = [[FutureEventsLocationViewController alloc] initWithStyle:UITableViewStylePlain];

    self.viewControllers = [NSArray arrayWithObjects:pastEventsLocationViewController, futureEventsLocationViewController, nil];
}

- (void)setupUI
{
    [self.segmentedControl addTarget:self action:@selector(indexDidChangeForSegmentedControl:) forControlEvents:UIControlEventValueChanged];
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    [super viewDidLoad];
    [self setupViewControllers];
    [self setupUI];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return YES;
}

@end

I can trigger the switch event and can log the currently selected index. But I don't have any idea where to go from here.

Maybe someone can turn my attention towards a certain direction...?

回答1:

This code works pretty well for your purpose, I use it for one of my new apps.
It uses the new UIViewController containment APIs that allow UIViewControllers inside your own UIViewControllers without the hassles of manually forwarding stuff like viewDidAppear:

- (void)viewDidLoad {
    [super viewDidLoad];
    // add viewController so you can switch them later. 
    UIViewController *vc = [self viewControllerForSegmentIndex:self.typeSegmentedControl.selectedSegmentIndex];
    [self addChildViewController:vc];
    vc.view.frame = self.contentView.bounds;
    [self.contentView addSubview:vc.view];
    self.currentViewController = vc;
}
- (IBAction)segmentChanged:(UISegmentedControl *)sender {
    UIViewController *vc = [self viewControllerForSegmentIndex:sender.selectedSegmentIndex];
    [self addChildViewController:vc];
    [self transitionFromViewController:self.currentViewController toViewController:vc duration:0.5 options:UIViewAnimationOptionTransitionFlipFromBottom animations:^{
        [self.currentViewController.view removeFromSuperview];
        vc.view.frame = self.contentView.bounds;
        [self.contentView addSubview:vc.view];
    } completion:^(BOOL finished) {
        [vc didMoveToParentViewController:self];
        [self.currentViewController removeFromParentViewController];
        self.currentViewController = vc;
    }];
    self.navigationItem.title = vc.title;
}

- (UIViewController *)viewControllerForSegmentIndex:(NSInteger)index {
    UIViewController *vc;
    switch (index) {
        case 0:
            vc = [self.storyboard instantiateViewControllerWithIdentifier:@"FooViewController"];
            break;
        case 1:
            vc = [self.storyboard instantiateViewControllerWithIdentifier:@"BarViewController"];
            break;
    }
    return vc;
}

I got this stuff from chapter 22 of Ray Wenderlichs book iOS5 by tutorial. Unfortunately I don't have a public link to a tutorial. But there is a WWDC 2011 video titled "Implementing UIViewController Containment"

EDIT

self.typeSegmentedControl is outlet for your UISegmentedControl

self.contentView is outlet for your container view

self.currentViewController is just a property that we're using to store our currently used UIViewController

回答2:

It's Matthias Bauch solution, but thought of sharing it in Swift anyway! Edit: Adding a link to a Swift 2.0 ready made demo app. https://github.com/ahmed-abdurrahman/taby-segmented-control

var currentViewController: UIViewController?
@IBOutlet weak var contentView: UIView!
@IBOutlet weak var segmentedControl: UISegmentedControl!

@IBAction func switchHappeningTabs(sender: UISegmentedControl) {
    if let vc = viewControllerForSelectedSegmentIndex(sender.selectedSegmentIndex) {
        self.addChildViewController(vc)
        self.transitionFromViewController(self.currentViewController!, toViewController: vc, duration: 0.5, options: UIViewAnimationOptions.TransitionFlipFromRight, animations: {
            self.currentViewController!.view.removeFromSuperview()
            vc.view.frame = self.contentView.bounds
            self.contentView.addSubview(vc.view)
            }, completion: { finished in
                vc.didMoveToParentViewController(self)
                self.currentViewController!.removeFromParentViewController()
                self.currentViewController = vc
            }
        )        
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    if let vc = self.viewControllerForSelectedSegmentIndex(self.segmentedControl.selectedSegmentIndex) {
        self.addChildViewController(vc)
        self.contentView.addSubview(vc.view)
        self.currentViewController = vc
    }
}

func viewControllerForSelectedSegmentIndex(index: Int) -> UIViewController? {
    var vc: UIViewController?
    switch index {
    case 0:
            vc = self.storyboard?.instantiateViewControllerWithIdentifier("FooViewController") as? UIViewController
    case 1:
            vc = self.storyboard?.instantiateViewControllerWithIdentifier("BarViewController") as? UIViewController
    default:
        return nil
    }

    return vc
}

回答3:

For someone want to implement the same in swift

import UIKit

class HomeController: UIViewController {

    var currentViewController:UIViewController?

    @IBOutlet weak var homeController: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let initialController:UIViewController = self.viewControllerForSegmentedIndex(0)

        self.addChildViewController(initialController)

        initialController.view.frame = self.homeController.bounds
        self.homeController.addSubview(initialController.view)
        self.currentViewController = initialController

    }

    @IBAction func segmentChanged(sender: UISegmentedControl) {

        let viewCOntroller:UIViewController = viewControllerForSegmentedIndex(sender.selectedSegmentIndex)

        self.addChildViewController(viewCOntroller)

        self.transitionFromViewController(self.currentViewController!, toViewController: viewCOntroller, duration: 0.5, options: UIViewAnimationOptions.TransitionFlipFromBottom, animations: {
            self.currentViewController?.view.removeFromSuperview()
            viewCOntroller.view.frame = self.homeController.bounds
            self.homeController.addSubview(viewCOntroller.view)

            }, completion:{ finished in

                viewCOntroller.didMoveToParentViewController(self)
                self.currentViewController?.removeFromParentViewController()
                self.currentViewController = viewCOntroller

        })

    }
    func viewControllerForSegmentedIndex(index:Int) -> UIViewController {
        var viewController:UIViewController?
        switch index {
        case 0:
            viewController = self.storyboard?.instantiateViewControllerWithIdentifier("StoryboardIdForFirstController")
            break
        case 1:
            viewController = self.storyboard?.instantiateViewControllerWithIdentifier("StoryboardIdForSecondController")
            break
        case 2:
            viewController = self.storyboard?.instantiateViewControllerWithIdentifier("StoryboardIdForThirdController")
            break
        default:
            break
        }
        return viewController!
    }
}

Storyboard view

回答4:

A is root view controller, and B, C is sub view controller. When you click segment, add sub view controller.

result

design

code

import UIKit

class SegmentViewController: UIViewController {

    @IBOutlet weak var containerView: UIView!

    var leftViewController: LeftViewController!
    var rightViewController: RightViewController!


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        if let sb = storyboard {
            leftViewController = sb.instantiateViewControllerWithIdentifier("leftViewController") as! LeftViewController

            switchViewController(from: nil, to: leftViewController)
        } else {
            print("storyboard is nil")
        }
    }

    func switchViewController(from fromVC: UIViewController?, to toVC: UIViewController?) {
        if let from = fromVC {
            from.willMoveToParentViewController(nil)
            from.view.removeFromSuperview()
            from.removeFromParentViewController()
        } else {
            print("fromVC is nil")
        }

        if let to = toVC {
            self.addChildViewController(to)
            to.view.frame = CGRectMake(0, 0, containerView.frame.width, containerView.frame.height)
            self.containerView.insertSubview(to.view, atIndex: 0)
            to.didMoveToParentViewController(self)
        } else {
            print("toVC is nil")
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.

        removeViewController()
    }

    func removeViewController() {
        if let leftVC = leftViewController {
            if let _ = leftVC.parentViewController {
                print("leftVC is using")
            } else {
                print("set leftVC = nil")
                leftViewController = nil
            }
        }

        if let rightVC = rightViewController {
            if let _ = rightVC.parentViewController {
                print("rightVC is using")
            } else {
                print("set rightVC = nil")
                rightViewController = nil
            }
        }
    }


    @IBAction func onSegmentValueChanged(sender: UISegmentedControl) {
        UIView.beginAnimations("xxx", context: nil)
        UIView.setAnimationDuration(0.4)
        UIView.setAnimationCurve(.EaseInOut)

        switch sender.selectedSegmentIndex {
        case 0:
            UIView.setAnimationTransition(.FlipFromRight, forView: self.containerView, cache: true)

            if let leftVC = leftViewController {
                switchViewController(from: rightViewController, to: leftVC)
            } else {
                if let sb = storyboard {
                    leftViewController = sb.instantiateViewControllerWithIdentifier("leftViewController") as! LeftViewController
                    switchViewController(from: rightViewController, to: leftViewController)
                } else {
                    print("storyboard is nil")
                }
            }
        default:
            UIView.setAnimationTransition(.FlipFromLeft, forView: self.containerView, cache: true)

            if let rightVC = rightViewController {
                switchViewController(from: leftViewController, to: rightVC)
            } else {
                if let sb = storyboard {
                    rightViewController = sb.instantiateViewControllerWithIdentifier("rightViewController") as! RightViewController
                    switchViewController(from: leftViewController, to: rightViewController)
                } else {
                    print("storyboard is nil")
                }
            }
        }

        UIView.commitAnimations()
    }
}

回答5:

You could embed your initial view controller in a navigation controller. Do that by selecting the view controller in the storyboard, then Editor->Embed in->Navigation Controller.

In your indexDidChangeForSegmentedControl: method you simply push the corresponding view controller to the navigation stack:

- (IBAction)indexDidChangeForSegmentedControl:(UISegmentedControl*)segmentedControl
{
    [self.navigationController pushViewController:[self.viewControllers objectAtIndex:[segmentedControl.selectedIndex]] animated:YES];

}

But your approach makes not too much sense at all when you are using storyboards. I don't know whether you can wire up a single segmented control button to a view controller using segues. Just try it.

回答6:

I ended up using a navigation controller to achieve a similar functionality.

import UIKit

class BaseViewController: UIViewController {

  var currentSegmentIndex = 0

  @IBOutlet weak var segmentedControl: UISegmentedControl!

  override func viewDidLoad() {
    super.viewDidLoad()

    segmentedControl.selectedSegmentIndex = currentSegmentIndex
  }

  @IBAction func segmentedControlChanged(_ sender: Any) {
    let idx = segmentedControl.selectedSegmentIndex
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    switch idx {
    case 0:
      let vc = storyboard.instantiateViewController(
        withIdentifier: "Foo") as! FooViewController
      vc.currentSegmentIndex = 0
      navigationController?.viewControllers = [vc]
      break
    case 1:
      let vc = storyboard.instantiateViewController(
        withIdentifier: "Bar") as! BarViewController
      vc.currentSegmentIndex = 1
      navigationController?.viewControllers = [vc]
      break
    default:
      break
    }
  }
}