I have a UINavigationViewController and inside that I have added a UITableViewController as a subview.
I'd like to be able to tell the UINavigationViewController pushViewController from inside the UITableViewController, but I am unable to retrieve the correct navigationController object.
I have tried some of the methods discussed in this thread, but I cannot get the navigationController for the view.
Is there a way to get a reference for the 'owning' view for a subview?
EDIT: I was able to do this:
[[(MyAppDelegate *)[[UIApplication sharedApplication] delegate] mainViewController].navigationController pushViewController:oOptionsViewController animated:YES];
To make it work. But the issue is just I'd like to do it without necessarily knowing the specific name of the navigationController (say it I have several of these instances, where I use the same class, but they may be used in other navigation controllers..)
I think what you've done there is perfect.
navigationController is an instance-variable, so each controller instance will get its own, and they can be set to different things depending on what navigation element they're added to.
Later,
Blake.
Related
In PrismForms we got the problem, that the NavigationStack is empty after navigating to a new page. That means after using the hardware back-button on the SecondPage, the app is closed. Although the back-arrow in the header on Android isnt shown. If looking closely you can see the back-arrow for a short moment after the page is switched. I guess thats before the NavigationStack gets cleared.
To the first page we navigate with the following command in OnInitialized() in our App.xaml.cs which derives from PrismApplication.
NavigationService.NavigateAsync("NavigationPage/StartPage");
(If only Navigating to „StartPage“ here, the Stack doesnt get cleared.)
That has do to with PageNavigationService.ProcessNavigationForNavigationPage(...) calling
bool clearNavStack = GetClearNavigationPageNavigationStack(currentPage); and PageNavigationService.ProcessNavigationForContentPage(...) not.
From the StartPage to the next we navigate with NavigateAsync("SecondPage")“. Here the described behaviour appears.
For navigation we use a class which wraps the Prism NavigationService. We hold him as a property and get him via Unity in our constructor:
this.PrismNavigation = prismNavigation ?? throw new ArgumentNullException(nameof(prismNavigation));
The methods „NavigateAsync“ and „GoBackAsync“, etc. we just pass through.
This way we want to seperate our ViewModel-Project from references to XamarinForms to later be able to use the same ViewModels for for example a WPF-GUI.
Why is the stack beeing cleared by our own NavigationService? If we register the original Prism NavigationService in App.xaml.cs instead, navigating back works as expected again. We found the point in the framework and could avoid the clearing with a drity hack, but that’s against the navigation-logic implemented in PrismForms, but we don’t understand how to do it the correct way.
Every help appreciated!
We edited a few things to get it working after finding some interesting information by Brian Lagunas in the forlast-post here:
https://github.com/PrismLibrary/Prism/issues/591
Although the topic was about something else, it led to improvements for overwriting the Navigation Service.
Remember that in your viewModels the Navigation Service must be named "navigationService" by convention. Also we switched from just holding the Prism Navigation Service as a parameter to deriving from it as suggested in the link above.
public class MyNavigationService : UnityPageNavigationService
I have been reading though a couple of examples and post but I just cannot figure out how to add a shortcut to my custom context menu. My GUI has several elements. One of them is a treeView. For the elements in my treeView I would like to have a custom context menu.
My first approach was according to this tutorial here. The context menu itself worked but the shortcuts cannot work if you create the actin within the show function.
So my second approach was according to this tutorial. But still my shortcuts do not work and if I use the context menu all actions are called twice...
Since I did not find a tutorial or code example, which matches my case, I hope that someone here can explain to me how this is correctly done in theory. Adding a shortcut to an action for a custom context menu.
Where do I have to declare my action?
What needs to be the parent of the action?
On which widget do I need to call addAction?
Thanks for any hints.
Another way is to add your action also to the parent widget (or main window widget). As mentioned in this reply, adding the same action to multiple widgets is fine and it's the way QActions are supposed to be used.
Example with custom HtmlBrowser class deriving from QTextBrowser:
Ctrl+U shortcut works for this code:
HtmlBrowser::HtmlBrowser(QWidget * parent) : QTextBrowser(parent)
{
viewSourceAct = new QAction(tr("View/hide HTML so&urce"), this);
viewSourceAct->setShortcut(tr("Ctrl+U"));
viewSourceAct->setCheckable(true);
parent->addAction(viewSourceAct);
connect(viewSourceAct, &QAction::triggered, this, &HtmlBrowser::viewSourceToggle);
}
and Ctrl+U shortcut does not work with this code (same as above, but without parent->AddAction(...)):
HtmlBrowser::HtmlBrowser(QWidget * parent) : QTextBrowser(parent)
{
viewSourceAct = new QAction(tr("View/hide HTML so&urce"), this);
viewSourceAct->setShortcut(tr("Ctrl+U"));
viewSourceAct->setCheckable(true);
connect(viewSourceAct, &QAction::triggered, this, &HtmlBrowser::viewSourceToggle);
}
Curiously, parent in this case is another widget (tab widget), not MainWindow. Still, adding parent->addAction() helps. And, unlike your suggested answer, it works even when connecting action to simple methods, without slots. Works for me in Qt 5.15.0. Not quite sure why it works, though. Perhaps, the widget the action is added to must be permanent for shortcuts to work? Looks like a bug in Qt.
Thanks to Scheff's hint I got it working. I do not now if this is really the correct way but this works for me.
The action needs to be declared in the constructor of your GUI class (e.g. MainWindow):
actionDel = new QAction(tr("delete"), this);
actionDel->setShortcut(QKeySequence(Qt::Key_Delete));
connect(actionDel, SIGNAL(triggered()), this, SLOT(actionDel_triggered()));
The triggered signal needs to be connected to a slot. Hint: if you create the slot do not use on_ACTIONNAME_triggered, this will interfere with the designer and cause a connection error.
Next add the action to a custom menu
fileContextMenu = new QMenu(this);
fileContextMenu->addAction(actionDel);
And to the widget
ui->treeView->setContextMenuPolicy(Qt::CustomContextMenu);
connect(ui->treeView, SIGNAL(customContextMenuRequested(QPoint)), this, SLOT(showDirContextMenu(QPoint)));
ui->treeView->addAction(actionDel);
All in the constructor of your GUI class.
To show the context menu use the following code in slot used in the above connect:
QModelIndex index=ui->treeView->indexAt(pos);
// Here you can modify the menu e.g. disabling certain actions
QAction* selectedItem = fileContextMenu->exec(ui->treeView->viewport()->mapToGlobal(pos));
If you do not have a slot for an action, the action can be also handled in the context menu slot, but this does not work with shortcuts!
if(selectedItem == actionOpen){
on_treeView_doubleClicked(index);
}
I have an iOS 6 app that I am updating to work with iOS 7 and to make it use storyboards. I am trying to use multiple storyboards so that I can break my project down into modules for each screen in the app. So far this has worked out fine but now I need to provide a way to navigate between the various storyboards while still making the work like it did in iOS 6 (but with updated artwork).
I don't use UINavigationController in my existing iOS 6 app and I would prefer not to use it as up to now I have been able to navigate back and forth between XIB's using code on UIButton tap gestures. The UINavigationController doesn't make it easy to customise how the navigation buttons look from what I have learned so far about it.
I found this very clean way of moving between view controllers that are on different storyboards https://github.com/rob-brown/RBStoryboardLink by passing the name of the storyboard in as an attribute.
But it only seems to work when UINavigationController is used. I get an error "Push segues can only be used when the source controller is managed by an instance of UINavigationController" without UINavigationController.
Is there a way to navigate between storyboards by only using the above RBStoryboardlink but without the need for UINavigationController?
Push segues can only be used when the source controller is managed by an instance of UINavigationController
This means you are trying to push a view controller to the source while source don't have any navigation controller stack.In that case, you should try to add the instantiated view controller's view as subview to the source view controller's view.
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *viewController = [mainStoryboard instantiateInitialViewController];
[self.view addSubview:viewController.view];
or you modally present, that purely depends on your requirement.
UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *viewController = [mainStoryboard instantiateInitialViewController];
tabBarViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:tabBarViewController animated:NO completion:NULL];
For some unknown reason I cannot push a view, I will try to explain the best I can but i have alot of complicated views going on, And it would be a nightmare to explain but say I have the following method.
-(void)showDetailView{
DetailViewController *detailView = [[DetailViewController alloc] initWithNibName:#"DetailViewController" bundle:nil];
[self.navigationController pushViewController:detailView animated:YES];
[detailView release];
}
Which works and would push the detail view onto the stack, this is on my main view and my main thread.
So in the table view i have a cell with a Subview that then takes its view from another view controller. In that view controller I have more subviews, and say when a user clicks a subview a method is called. Which in turn will call this method on the mainView.
So one would believe that then a new view should get pushed. And the code runs, no errors occur but the view is not changed/switched.
I have tried various method of pushing a view inside the view controller that is it called from. and then just calling a method which is directly connected to the navigation controller to push the views.
A few things to add.
1. I have a IBAaction button that pushes a view (that works fine)
2. I assume its because im through so many views but I'm assuming that if you call push view controller it will push whatever view you pass it.
3. I have checked when the method is called from the main view self.navigationcontroller does not = null.
But if the navigation controller is called through the method call it = null.
So is there anyway to restore the null value of a navigation controller?
Im a little confused on why i cant simply call a method to push a view
Thanks
Its ok I have sorted it now
In terms of how i solved accessing the superior superview to my view is
An ID tag to the views superview which is the cell that my subview is in
id CellController = [self.view.superview.superview nextResponder];
[CellController performSelector:#selector(showDetailView:) withObject:Link];
Then calling a method in my cell which then in turn access its superview
id mainController = [self.view.superview.superview nextResponder];
[mainController performSelector:#selector(showDetailView:) withObject:Link];
Which then the main still retains its navigation controller and then in the show detail method in the main passes the link and pushes the new view.
Basically the total superview of a subview can be no higher then wherever it was created. So the subview in my cell could never access and run anything through my mainView properly, i could stuff but it never performed how it should be. So accessing its highest level superview and then getting that to access its superview as the cell is in my main view then I could run methods correctly.
Hope this makes sense only getting my head around it all.
Thanks to -> How does one access a super's view controller?
For the Id tag bit, not used Id in this way so another things learnt
I just had nearly the same problem today. If the navigation bar is hidden when you push a view, you may have a nil navigation controller. I resolve the problem like this :
self.navigationController.navigationBarHidden = NO; // So the navigation controller is not nil
[self.navigationController pushViewController:articleInfoController animated:YES];
I currently have a tab bar controller set up with a navigationcontroller on one of the tabs, then I have a UITableView nib set up for that Navigationcontrollers view. All of this has been set up through IB and I want to keep it that way. Kind of like this tutorial http://twilloapp.blogspot.com/2009/05/how-to-embed-navigation-controller.html
now the view loads perfectly when ViewDidLoad is called. But when I then load further views via code IE
MyApp_AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
UINavigationController *nav = (UINavigationController *)delegate.controller.selectedViewController;
newViewController = [[newViewController alloc] initWithNibName:#"newView" bundle:nil];
[nav pushViewController:newViewController animated:YES];
//At this point the view works! and loads
If I try to go back with the navigation toolbar it goes back to my previous view fine
Now I need to refresh the tableview when I go back but calling viewDidAppear does not work.
I tried adding UINavigationDelegate to the same ViewController Class as the tableview and then calling - (void)navigationController:(UINavigationController *)navigationController didShowViewController:
But that did not work. I also tried adding the same delegate as the tab bar controller and adding the same navigationController didShowViewController: there but that also failed.
How do I get this table to refresh every time the view loads?
You should not have to call viewDidAppear from your code. Cocoa Touch should do that for you.
Call the table view's reloadData method to get it to refresh its contents.
Found I was missing the Delegate declaration in the Interface file. doh! also I tried that in lots of places it only ended up working when I added it to the NavigationControllers first view (my table view)