Force Landscape Orientation on iOS 6 in Objective-

问题:

I have a master view controller that's inside a UINavigationController. In that master view controller, I have a button that pushes a detail view controller that has a UIWebView inside of it. I want this detail view controller to be on landscape mode when it's loaded. Going back to the master view controller, it forcibly goes back again to portrait mode. I'm running iOS 6 on this.

I have seen the other similar questions but it's not working on my end. I have created a LandscapeViewController that's a subclass of UIViewController where I have written these methods:

#pragma mark - Orientation Methods
- (NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskLandscape;
}

- (BOOL)shouldAutorotate
{
    return YES;
}

This is my code when I push the detail view controller:

DetailViewController *detailVC = [[DetailViewController alloc]
                                      initWithNibName:@"DetailViewController"
                                      bundle:nil];

    [self.navigationController pushViewController:detailVC
                                         animated:YES];

I'm thinking on where to subclass my LandscapeViewController on the code above to make it work or on how to properly subclass and push my detail view controller. I can also present my detail view controller modally if it's not possible for the navigation controller to push my detail view controller from portrait to landscape. Where am I doing it wrong?

回答1:

Considering: View A: Portrait only - View B: Landscape only

I couldn't do it in the navigation controller. Instead what I did was to open a modal view from view A to view B and force a new navigation controller into this view.

This is working for me in iOS5+.

You need to create a category for the navigation controller like this:

UINavigationController+Rotation_IOS6.h

#import <UIKit/UIKit.h> 

@interface UINavigationController (Rotation_IOS6)

- (BOOL)shouldAutorotate;
- (NSUInteger)supportedInterfaceOrientations;
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation;

@end

UINavigationController+Rotation_IOS6.h

#import "UINavigationController+Rotation_IOS6.h"

@implementation UINavigationController (Rotation_IOS6)

- (BOOL)shouldAutorotate
{
    return [self.topViewController shouldAutorotate];
}

- (NSUInteger)supportedInterfaceOrientations
{
    return [self.topViewController supportedInterfaceOrientations];
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return [self.topViewController preferredInterfaceOrientationForPresentation];
}

@end

In AppDelegate.m add:

- (NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window{
    return UIInterfaceOrientationMaskAll;
}

Then in View A:

- (BOOL)shouldAutorotate {
    return YES;
}

-(NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskPortraitUpsideDown;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return UIInterfaceOrientationPortrait;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait || interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown);
}

also in View A to open View B do this:

ViewB *vc = [[ViewB alloc] initWithNibName:@"ViewB" bundle:nil];

UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:vc];

[self presentViewController:navigationController animated:YES completion:nil];

And, finally, in View B

- (BOOL)shouldAutorotate {
    return YES;
}

-(NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskLandscapeRight | UIInterfaceOrientationMaskLandscapeLeft;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return UIInterfaceOrientationLandscapeRight;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationLandscapeRight || interfaceOrientation == UIInterfaceOrientationLandscapeLeft);
}

回答2:

They kinda screwed the pooch in iOS 6 with regard to this. Here's what I've figured out so far:

First off, Apple added the "Supported Interface Orientations" buttons with Xcode 4.5. This corresponds to the "Supported interface orientations" attribute in _info.plist. These buttons must be toggled to the correct choices before any of the rest will work. (If the buttons seem to refuse to toggle it's likely because the info.plist is locked by CVS or some other process.)

Next, the property .window.rootViewController must be set, and must point to the "bottom" view controller in the stack. Generally this will be either a navigation controller or a tab controller.

If the desire is to disable all rotation, this can be done using the buttons, or one can implement, in the "bottom" view controller, the "shouldAutorotate" method and have it return NO. (If the method is omitted then the default is YES.)

In spite of having autorotation disabled with shouldAutorotate, if there is a MPMoviePlayerViewController being displayed, that will autorotate. Only toggling the supported interface orientation buttons appears to prevent this.

If one wants to conditionally autorotate other view controllers it gets messier. Basically, your "bottom" view controller must implement the supportedInterfaceOrientations method and return, based on the current topViewController, the appropriate bit mask. This can be done with a routine that queries the topViewController's old "shouldAutorotateToInterfaceOrientation" method, but it's a bit ugly. And even though this scheme doesn't require modifying the rotating view controller's code, you DO need to modify the VC just "below" the rotated one to implement "supportedInterfaceOrientation", or else that view will be rotated on return. (At least this is a simple copy/paste.) No one seems to have come up with a better, more general scheme, though.