I have a standard Master-Detail Interface and I'm using Coredata and cocoa bindings.
The Master list uses a NSOutlineView and a NSTreeController, these items remain static but different details views are swapped in and out.
So, how do I set the content of the array controllers in the different detail views to correspond to the selection in the outlineview in the Masterview?
This is straight forward if all the array/treecontrollers are in the same .xib file. initially, I tried creating an Outlet from of the Treecontroller and passing this to the orther views as they are created, but I don't think this is correct.
Any suggestions?
You can use an array controller or a tree controller for as many views as you like. In your specific example, I would make the masterview owner of the tree-controller (unless you have a compelling reason to go yet another level up). Then each detail view that gets swapped-in would also have view controllers. That controller would have an assignable "tree-controller" property that would get set before its view is loaded to the value of the "master" tree-controller. Within the Nib files you can use bindings (to the tree-controller of files-owner) as you normally would.
Related
I have dynamic view panel and I am using a customizer bean to hide columns based on column names. However, I need to:
Know which view is loaded in the customizer bean
get document handle in the bean
add additional column in the bean
Why I need this: in my application I am dealing with document mappings. I want to create a column for mapped document details. as there can be different document types mapped, there can be multiple columns.
The work of seeing which view you're working with and generating the column defs (normally the same as the ones in the view, but you could add others) is done via the ViewFactory object that is returned by #getViewFactory in the customizer bean. You can see an example of overriding the method and returning a customized factory here. You can also find the source of the default one in the ExtLib here for another example. The job of the ViewFactory is to emit a ViewDef containing a series of ColumnDefs - basically, an abstract representation of the view design. That will cover 1 and 3.
Getting a handle on the document in question for number 2 is a bit more indirect. Since the customizer bean executes only during the initialization of the view, it has no direct hook to the process of rendering each row (which is where you can get the document). You can, however, set properties or content to method/value bindings that, themselves, access the document, so that they're executed per row. I do this in order to get color columns working: I create an SSJS binding for the style property that can then see the viewEntry object. If you modify that code, you could write some SSJS like #{javascript:var doc = viewEntry.getDocument(); ...other stuff here...}. If you do that, you should make sure to either always use "viewEntry" as the var name in the view or use panel.getVar() to find the variable name dynamically.
I am trying to pass a simple core data objects info from a tabBarController to its subviews so that they each reference a different attribute of that object. As a newbie, I'm not sure even where to start. It doesn't seem to be as simple as passing the data from one tableView to another...
Thank you for any help.
If you are sharing the same object between (most of the) the view controllers of your tab bar controller, maybe the best architecture for this would be to have one central data object.
A typical pattern is a singleton, some kind of data manager that provides the object, but maybe that is overkill. Another is to keep references to all view controllers and update them one by one when something changes - also not very elegant.
What you really want is something like a global variable. You could (ab)use your app delegate (just give it a property that points to the object) or if you prefer even your tab bar controller (make a subclass, give it a property). In the latter case, every view controller could then get the object like this:
NSManagedObject *object = [(MyCustomTabBarController*)self.tabBarController object];
For example, you can check for changes and refresh your views in viewWillAppear.
A UITabBarController should be handling other view controllers, not handling data objects. How does the tab bar controller get the object reference in the first place? And what is the object you're sharing?
Let each of your subordinate VC's keep a pointer to the object, and then they can each follow the appropriate keypath to get to the entities they're designed to handle.
Tim Roadley's book Learning Core Data for iOS, in chapters 5 and 6, shows how to pass an object from one view controller (a table view) to a detail view. It doesn't sound like that's what you're asking, but just in case...
In response to comment:
I'm looking at a tableview, tap a cell, and then a tab bar controller slides in? That's not the usual visual metaphor for a tab bar; it's meant for changing modes for the entire program. See the Music app for a typical example: songs, playlists, artists.
But if you really need to do it that way, try this (I'm assuming you're using storyboards):
In prepareForSegue: in your tableview controller, tell the destination (tab bar controller) what object it's working with.
In the tab bar controller's -viewWillAppear, tell each of its tabs about the attribute: self.frobisherViewController.frobisher = self.myWidget.frobisher.
You could instead tell each of the component tabs about the top level object: self.frobisherViewController.widget = self.myWidget. But I like the first approach better because there is less linkage. The frobisherViewController now would need to know about both widgets and frobishers.
This ended up being very simple. I was trying to call the object in the child views initWithNibName which doesn't work. I ended up creating a setObject function and calling the properties I wanted in viewWillAppear.
Hope this helps someone.
I would like to make a layout with a sidebar that can have widgets from different modules. Lets say there shall always be a login widget at the top if the user isn't logged in then it shall show user info. The getting started album guide could use it to display the latest albums and so on, i hope you understand how i want to use the sidebar.
Could it be done with a config file in autoload and a small code that read that config and calls the widgets on every page load?
There are several ways of page composition in Zend Framework 2:
1. Switching between Layouts
By default, ZF2 provides you with a single layout template layout.phtml.
In real-life applications, you will probably need to have several layouts
and switch the layout for certain controller/action. In each of your layouts, you will be able to show different widgets/sidebars.
2. Partial Views
A partial view is a .phtml view template file which can be rendered by another
view template. Partial views allow to compose your page of pieces and reuse pieces
of view rendering logic across different view templates. This is accomplished through the Partial view helper.
3. Placeholder View Helper
The Placeholder is another useful view helper allowing for capturing HTML
content and storing it for later use. Thus, analogous to the Partial
view helper, it allows to compose your page of several pieces.
4. Forward Controller Plugin
With the Forward controller plugin, you are able to call an action (for example, the action rendering some widget) from another module/controller from your controller and grab the output of that action. Then you are able to incorporate that output into your page.
5. Use View Models for Page Composition
When you write action methods for the controller classes, you use the ViewModel
class as a variable container for passing the variables from controller to view template,
and for overriding the default view template name. But, actually the ViewModel class is more than just a variable container plus view template name. In fact, it is closely related to the layout and page composition.
The third big capability of the view model class is that it allows for combining several
view models in a tree-like structure. Each view model in the tree has the associated
view template name and data variables that can be passed to the view template to control
the process of rendering.
This feature is internally used by Zend Framework 2 when "combining" the layout view template and the view template associated with the controller's action method. ZF2 internally creates the view model for the layout template and assigns it with layout/layout view template name. When your controller's action method returns the ViewModel object, this object is attached as a child to the layout view model.
So, you can attach your own view models to the default view model to render the page of pieces that you want.
I have a MainView which has an associated MainViewModel in my WPF application, assigned via its contructor.
App > start up uri > MainWindow.xaml
public MainWindow()
{
InitializeComponent();
var viewModel = new MainViewModel();
DataContext = viewModel;
}
My MainView holds as many as four nested views or child views who are hidden and displayed based upon the button that has been clicked on the MainView. So we toggling the visibility property vi a binding which gets updated via command bindings assigned to each button on the MainView.
Each nested View does not have an associated ViewModel, all bindings found on child views find their information in the MainViewModel. So binding system ends waling up the UI tree of the app to find out that the parent 'MainView' has an associated ViewModel.
So overall there is 'ONE' -> ViewModel. This seems to work fine and but as expected this VM has gotten to big and needs re-factoring. It holds information that contextually it should not. But this is a proof concept application. So i decided to keep it simple and make sure it was do-able.
PROBLEM:
When i tried assigning a empty view with an empty view model I noticed binding errors in the output window and as expected weird and broken behaviour. Which makes no sense ... Is there a more clear and concise way of letting WPF know how to handle any bindings it finds in a nested view control? I thought if each view's constructor assigned itself a corresponding VM as shown above, then it should work as this logically makes sense. Unfortunately all buttons on the MainView stop working when the corresponding view it is designated to switch on and hide the others has an associated ViewModel. On some buttons it works and the others it does not? This is really weird?
As mentioned in my answer above, the problem was that WPF binding system was struggling to to resolve bindings at run time. The main view has its associated view model instantiated and assigned via the Main View contructor and this pattern is repeated for all nested views that the MainView also houses.
By default, I tend to use the implied binding syntax which means that without explicitly specifiying a source the binding system will try to resolve the name you supply in the binding. So it's all implied and nothing is explicitly set!
Upgrading each nested view to have its own view model makes this auto discovery/resolution of bindings go a little crazy and I have not explicitly told the binding system where to find the property I am looking for hence the output window binding errors.
This leads to unexpected behaviour as the output window was telling that it was trying to resolve binding expressions in nested views --> viewmodels. When in actual fact that VM it is looking in, IS EMPTY!
So clearly the binding system is good when you do not explicitly set a source property inside the binding syntax. It is clever enough to find things on its own. In my case it needed some extra help, as it was unsure as to where to find things.
SOLUTION:
Remove the constructor declaration for the MainViewModel in the MainView constructor.
Scope in an xmlns for ViewModels namesapce into your MainView.xaml
Create a window resource inside the MainView .xaml
Give the resource a key.
Upgrade all your bindings in the MainView xaml file to include source property.
Give the source property a static resource binding that points to your ViewModel key value set up in step 4.
Only do step 6 for bindings who refer to the ViewModel that is associate with the MainView.
All nested views are to be left alone, they should handle their own bindingds in their own xaml files. The MainView simply instantiates them and places them onto the UI. For me this was the case, I did not have any more bindings concerning my nested views. All Bindings that lived on the MainView.xaml file referred to data in the MainViewModel.cs. This makes alot easier when viewing your problem.
For some reason the editor was being awkward so I chose to omit any sample code but the steps above are descriptive enough to follow the steps that I took. Above is what worked for me.
ANOTHER WAY OF SUMMING UP THIS PROBLEM
Most books teach the shorter binding syntax
What happens when more than one data context is available?
How is the binding system supposed to know how to resolve your short hand binding expressions.
my question is about view controllers, delegates and all that in general. I feel perfectly comfortable with UIView, UIViewController, Delegates and Sources, like UITableView does for instance. It all makes sense.
Now I have implemented my first real custom view. No XIBs involved. It is an autocomplete address picker very much like in the Mail application. It creates those blue buttons whenever a recipient is added and has all the keyboard support like the original.
It subclasses UIView. There is no controller, no delegate, no source. I wonder if I should have either one of those? Or all, to make it a clean implementation.
I just cannot put my finger on the sense a view controller would make in my case. My custom view acts much like a control and a UIButton doesn't have a controller either.
What would it control in my view's case?
Some of my thoughts:
For the source: currently the view has a property "PossibleAutocompleteRecipients" which contains the addresses it autocompletes. I guess this would be a candidate for a "source" implementation. But is that really worth it? I would rather pass the controller to the view and put the property into the controller.
The selected recipients can be retrieved using a "SelectedRecipients" property. But views should not store values, I learned. Where would that go? Into the controller?
What about all the properties like "AllowSelectionFromAddressBook"? Again, if I compare with UIButton, these properties are similar to the button's "Secure" property. So they are allowed to be in the view.
The delegate could have methods like "WillAddRecipient", "WillRemoveRecipient" and so on and the user could return TRUE/FALSE to prevent the action from happening. Correct?
Should I maybe inherit from UIControl in the first place and not from UIView?
And last but not least: my custom view rotates perfectly if the device is rotated. Why don't all views? Why do some need a controller which implements ShouldAutoRotateToDeviceOrientation()?
Does it make sense what I wrote above? In the end I will provide the source on my website because it took me some time to implement it and I would like to share it as I have not found a similar implementaion of the Mail-App-like autocomplete control in MonoTouch.
I just want to learn and understand as much as possible and include it in the source.
René
I can answer part of your question.
I just cannot put my finger on the
sense a view controller would make in
my case
The ViewController is responsible for handling the View's state transitions (load, appear, rotate, etc) These transitions are used mainly when you use a navigation component (UINavigationViewController, UITabBarController). These components needs to received a ViewController that will handles the view's transitions.
For exemple, when you push a ViewController on a UINavigationViewController, it will cause the ViewDidLoad, ViewWillAppear, ViewDidAppear. It will also cause the ViewWillDisappear, ViewDidDisappear of the current ViewController.
So, if your application has only one portrait view, you don't need a ViewController. You can add your custom view as a subview of the main window.