UITabBar 在旋转时更改所有视图

Question

I have a tab bar controller with multiple views. Each of the views has a toolbar. I added code to apply a background image to the toolbar.

I also added code, in viewdidLoad, on each view to fire when the device is rotated so I can apply a different background image for landscape mode:

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];

NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
[notificationCenter addObserver:self selector:@selector(didRotate:)
name:@"UIDeviceOrientationDidChangeNotification" object:nil];

If I run the app and rotate, the first view works, but then going to other tabs causes the didRotate method to not fire, since the device has already rotated.

How can I make all the views update when the device rotates?

Answer 1

What you should do is to check the interfaceOrientation on viewWillAppear: and re-layout the UI if needed.

Answer 2

You do not necessarily need notifications. You can accomplish this using the two methods

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toOrientation 
                                duration:(NSTimeInterval)duration

and

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation 

For example, to make the tabBar hide in landscape mode but not in portrait, use this:

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

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toOrientation 
                                duration:(NSTimeInterval)duration
{
        if (toOrientation == UIInterfaceOrientationLandscapeLeft ||
            toOrientation == UIInterfaceOrientationLandscapeRight) {
            [[self view] endEditing:YES];
            [[self view] addSubview:graphView];
            //[[UIApplication sharedApplication] setStatusBarHidden:TRUE withAnimation:FALSE];
            [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackOpaque];
            [self.navigationController setNavigationBarHidden:TRUE animated:TRUE]; 
        }       

}

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation 
{ 
    UIInterfaceOrientation toOrientation = self.interfaceOrientation;

    if ( self.tabBarController.view.subviews.count >= 2 )
    {
        UIView *transView = [self.tabBarController.view.subviews objectAtIndex:0];
        UIView *tabBar = [self.tabBarController.view.subviews objectAtIndex:1];

        if(toOrientation == UIInterfaceOrientationLandscapeLeft ||
           toOrientation == UIInterfaceOrientationLandscapeRight) {                                     
            transView.frame = CGRectMake(0, 0, 480, 320 );
            tabBar.hidden = TRUE;
        }
        else
        {                               
            transView.frame = CGRectMake(0, 0, 320, 480);         
            tabBar.hidden = FALSE;
        }
    }
}