Blackberry - Disable Save option in BasicEditField? - user-interface

I am using a basiceditfield to take input from the user to do some simple string search. But if i type a few letters and wish to go back without continuing the search, it automatically asks me whether to save the contents of the field. I don want this to happen. Can i in any way disable the "Changes made!-save-discard-cancel" option in basiceditfield(or any editfield for that matter)????please help!!!

Try adding this to your MainScreen class:
protected boolean onSavePrompt() {
return true;
}

Another way would be to override the dirty state logic on your Screen class like this:
public boolean isDirty() { return false; }
Of course you can also just override that same method on a subclass of your Field, and that too should probably work. (assuming you still want to do dirty-state-tracking of other fields on the screen.)

modify onClose method of Screen
public boolean onClose() {
this.close();
return true;
}

Related

How to handle back button when at the starting destination of the navigation component

I've started working with the new navigation component and I'm really digging it! I do have one issue though - How am I supposed to handle the back button when I'm at the starting destination of the graph?
This is the code I'm using now:
findNavController(this, R.id.my_nav_host_fragment)
.navigateUp()
When I'm anywhere on my graph, it's working great, it send me back, but when I'm at the start of it - the app crashes since the backstack is empty.
This all makes sense to me, I'm just not sure how to handle it.
While I can check if the current fragment's ID is the same as the one that I know to be the root of the graph, I'm looking for a more elegant solution like some bool flag of wether or not the current location in the graph is the starting location or not.
Ideas?
I had a similar scenario where I wanted to finish the activity when I was at the start destination and do a regular 'navigateUp' when I was further down the navigation graph. I solved this through a simple extension function:
fun NavController.navigateUpOrFinish(activity: AppCompatActivity): Boolean {
return if (navigateUp()) {
true
} else {
activity.finish()
true
}
}
And then call it like:
override fun onSupportNavigateUp() =
findNavController(R.id.nav_fragment).navigateUpOrFinish(this)
However I was unable to use NavigationUI as this would hide the back arrow whenever I was at the start destination. So instead of:
NavigationUI.setupActionBarWithNavController(this, controller)
I manually controlled the home icon:
setSupportActionBar(toolbar)
supportActionBar?.setDisplayHomeAsUpEnabled(true)
supportActionBar?.setHomeAsUpIndicator(R.drawable.ic_navigation_back)
Override onBackPressed in your activity and check if the current destination is the start destination or not.
Practically it looks like this:
#Override
public void onBackPressed() {
if (Navigation.findNavController(this,R.id.nav_host_fragment)
.getCurrentDestination().getId() == R.id.your_start_destination) {
// handle back button the way you want here
return;
}
super.onBackPressed();
}
You shouldn't override "onBackPressed", you should override "onSupportNavigateUp" and put there
findNavController(this, R.id.my_nav_host_fragment)
.navigateUp()
From the official documentation:
You will also overwrite AppCompatActivity.onSupportNavigateUp() and call NavController.navigateUp
https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing
In Jetpack Navigation Component, if you want to perform some operation when fragment is poped then you need to override following functions.
Add OnBackPressedCallback in fragment to run your special operation when back present in system navigation bar at bottom is pressed .
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
onBackPressedCallback = object : OnBackPressedCallback(true) {
override fun handleOnBackPressed() {
//perform your operation and call navigateUp
findNavController().navigateUp()
}
}
requireActivity().onBackPressedDispatcher.addCallback(onBackPressedCallback)
}
Add onOptionsItemMenu in fragment to handle back arrow press present at top left corner within the app.
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
setHasOptionsMenu(true)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
if (item.itemId == android.R.id.home) {
//perform your operation and call navigateUp
findNavController().navigateUp()
return true
}
return super.onOptionsItemSelected(item)
}
If there is no special code to be run when back is pressed on host fragment then use onSupportNavigateUp in Activity.
override fun onSupportNavigateUp(): Boolean {
if (navController.navigateUp() == false){
//navigateUp() returns false if there are no more fragments to pop
onBackPressed()
}
return navController.navigateUp()
}
Note that onSupportNavigateUp() is not called if the fragment contains onOptionsItemSelected()
As my back button works correctly, and using NavController.navigateUp() crashed on start destination back button. I have changed this code to something like this. Other possibility will be to just check if currentDestination == startDestination.id but I want to close Activity and go back to other Activity.
override fun onSupportNavigateUp() : Boolean {
//return findNavController(R.id.wizard_nav_host_fragment).navigateUp()
onBackPressed()
return true
}
/** in your activity **/
private boolean doubleBackToExitPressedOnce = false;
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
public void onBackPressed() {
int start = Navigation.findNavController(this, R.id.nav_host_fragment).getCurrentDestination().getId();
if (start == R.id.nav_home) {
if (doubleBackToExitPressedOnce) {
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(MainActivity.this, "Press back again to exits", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
doubleBackToExitPressedOnce = false;
}
}, 2000);
} else {
super.onBackPressed();
}
}
If you mean the start of your "root" navigation graph (just incase you have nested navigation graphs) then you shouldn't be showing an up button at all, at least according to the navigation principles.
Just call this in your back button Onclick
requireActivity().finish()

Make changes to buttons and labels in an XML Ribbon during run-time

I know there are several topics already on stackoverflow, but nothing that actually solves the problem. Here it is:
Because of some inherent problems with Ribbon Designer I decided to build my next Excel AddIn using XML Ribbon.
However, occasionally I need to make changes to the controls in the ribbon based on user selections. For example I need to change the text of a label, and also make some of the controls disabled in some cases. And here's where I hit a brick wall. It looks like there's no way to do it. I tried to put the logic in the onAction callback as follows:
public void LabelAction(IRibbonControl control)
{
LabelControl label = (LabelControl)control;
label.Label = "changed text";
}
But this cast doesn't work because apparently IRibbonControl interface has nothing to do with the RibbonControl class that LabelConrol inherits from.
I was also not able to find any other way to access any of the XML ribbon controls. Is there even a solution to this? Or should I stick to Ribbon Designer?
You need to do this in a routine that sets the item label.
The xml would look like this:
<button id="SkLabelTest1" getLabel="GetLabelTest" onAction="SkLabelTest1"/>
<button id="SkLabelTest2" getLabel="GetLabelTest" onAction="SkLabelTest2"/>
The routine you are interested in is getLabel
I've done a noddy routine to demonstrate this.
First I added a property to ThisAddin.cs for it to read:
public string _labelTest = string.Empty;
public string LabelTest { get { return _labelTest; } set { _labelTest = value; } }
Then in my ribbon handling code I added the getLabel routine:
public string GetLabelTest(Office.IRibbonControl control)
{
switch (control.Id.ToLower())
{
case "sklabeltest2":
if (Globals.ThisAddIn.LabelTest != string.Empty)
return Globals.ThisAddIn.LabelTest;
else
return "Label Test 2";
default:
return "Label Test 1";
}
}
This works by the SkLabelTest1 button changing the text of SkLabelTest2 and then invalidating the control to force the ribbon to reload it:
public void SkLabelTest1(Office.IRibbonControl control)
{
Globals.ThisAddIn._labelTest = "Changed text";
Globals.ThisAddIn._ribbon.InvalidateControl("SkLabelTest2");
}
I've tested just in case and it changes the text OK. Hope this helps
I couldn't make a comment because of my reputation. As a comment to Charlie's post, it is a perfect solution but on my side, I had to change one part.
I changed public void SklabelTest1 function to this one below:
public void SkLabelTest1(Office.IRibbonControl control)
{
Globals.ThisAddIn._labelTest = "Changed text";
this.ribbon.InvalidateControl("SkLabelTest2");
}
And also added this in the beginning of my ribbon class.
private Office.IRibbonUI ribbon;
I hope it helps.

Conditional AJAX confirm with a new value in Wicket

I need to solve a simple problem, but yet I have not been able to found out any solution yet.
I have a simple DropDownChoice with AJAX onChange() JS event. I need to add a confirm box before the onUpdate() action is done - this is not difficult, BUT I need to display the confirm box only if the new selected value of the DropDownChoice is X (one certain value), and do not display the confirm box in any other case. Is it doable?
Short example snippet:
DropDownChoice<Integer> choice = new DropDownChoice<Integer>("id", new Model<Integer>(0));
choice.add(new AjaxFormComponentUpdatingBehavior("onchange") {
#Override
protected void onUpdate(AjaxRequestTarget target) {
// do some stuff
}
#Override
protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
super.updateAjaxAttributes(attributes);
attributes.getAjaxCallListeners().add(new AjaxCallListener() {
#Override
public CharSequence getPrecondition(Component component) {
return "return confirm('Really?')"; // I NEED THIS DISPLAYED CONDITIONALLY
}
}
}
}
I don't know how to access the "choice" model object (converted input...) with the proposed value to add it to a condition in updateAjaxAttributes() method.
Thank you.
I think you should go for a JavaScript-based solution. The code of AJAX call listener is executed in a scope where you can use variable attrs. This variable contains the parameters used to perform AJAX call, including the id of the component. In this way you could check for selected value.
See more at http://wicket.apache.org/guide/guide/ajax.html#ajax_5

JavaFX: Prevent selection of a different tab if the data validation of the selected tab fails

I'm creating a CRUD application that store data in a local h2 DB. I'm pretty new to JavaFX. I've created a TabPane to with 3 Tab using an jfxml created with Scene Builder 2.0. Each Tab contains an AncorPane that wrap all the controls: Label, EditText, and more. Both the TabPane and the Tabs are managed using one controller. This function is used to create and to update the data. It's called from a grid that display all the data. A pretty basic CRUD app.
I'm stuck in the validation phase: when the user change the tab, by selecting another tab, it's called a validation method of the corresponding tab. If the validation of the Tab fails, I want that the selection remains on this tab.
To achieve this I've implemented the following ChangeListener on the SelectionModel of my TabPane:
boolean processingTabValidationOnChange = false;
tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {
#Override
public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
if (processingTabValidationOnChange == false) {
boolean success;
switch (t.intValue()) {
case 0: success = validationTab1Passed();
break;
case 1: success = validationTab2Passed();
break;
case 1: success = validationTab3Passed();
break;
default: success = false;
}
if (success == false) {
processingTabValidationOnChange = true;
// select the previous tab
tabPane.getSelectionModel().select(t.intValue());
processingTabValidationOnChange = false;
}
}
}
});
I'm not sure that this is the right approach because:
The event changed is fired two times, one for the user selection and one for the .select(t.intValue()). To avoid this I've used a global field boolean processingTabValidationOnChange... pretty dirty I know.
After the .select(t.intValue()) the TabPane displays the correctly Tab as selected but the content of the tab is empty as if the AnchorPane was hidden. I cannot select again the tab that contains the errors because it's already selected.
Any help would be appreciated.
Elvis
I would approach this very differently. Instead of waiting for the user to select a different tab, and reverting if the contents of the current tab are invalid, prevent the user from changing tabs in the first place.
The Tab class has a disableProperty. If it is set to true, the tab cannot be selected.
Define a BooleanProperty or BooleanBinding representing whether or not the data in the first tab is invalid. You can create such bindings based on the state of the controls in the tab. Then bind the second tab's disableProperty to it. That way the second tab automatically becomes disabled or enabled as the data in the first tab becomes valid or invalid.
You can extend this to as many tabs as you need, binding their properties as the logic dictates.
Here's a simple example.
Update: The example linked above is a bit less simple now. It will dynamically change the colors of the text fields depending on whether the field is valid or not, with validation rules defined by bindings in the controller. Additionally, there are titled panes at the top of each page, with a title showing the number of validation errors on the page, and a list of messages when the titled pane is expanded. All this is dynamically bound to the values in the controls, so it gives constant, clear, yet unobtrusive feedback to the user.
As I commented to the James's answer, I was looking for a clean solution to the approach that I've asked. In short, to prevent the user to change to a different tab when the validation of the current tab fails. I proposed a solution implementing the ChangeListener but, as I explained: it's not very "clean" and (small detail) it doesn't work!
Ok, the problem was that the code used to switch back the previous tab:
tabPane.getSelectionModel().select(t.intValue());
is called before the process of switching of the tab itself it's completed, so it ends up selected... but hidden.
To prevent this I've used Platform.runLater(). The code .select() is executed after the change of tab. The full code becomes:
//global field, to prevent validation on .select(t.intValue());
boolean skipValidationOnTabChange = false;
tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {
#Override
public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
if (skipValidationOnTabChange == false) {
boolean success;
switch (t.intValue()) {
case 0:
success = validationTab1Passed();
break;
case 1:
success = validationTab2Passed();
break;
case 1:
success = validationTab3Passed();
break;
default:
success = false;
}
if (success == false) {
Platform.runLater(new Runnable() {
#Override
public void run() {
skipValidationOnTabChange = true;
tabPane.getSelectionModel().select(t.intValue());
skipValidationOnTabChange = false;
}
});
}
}
}
});
Anyway, if anyone has a better solution to accomplish this, you're welcome. In example using a method like consume() to prevent the tab to be selected two times. This way I can eliminated the global field skipValidationOnTabChange.
Elvis
I needed to achieve the similar thing. I've done this by changing the com.sun.javafx.scene.control.behavior.TabPaneBehaviour class by overriding selectTab method:
class ValidatingTabPaneBehavior extends TabPaneBehavior {
//constructors etc...
#Override
public void selectTab(Tab tab) {
try {
Tab current = getControl().getSelectionModel().getSelectedItem();
if (current instanceof ValidatingTab) {
((ValidatingTab) current).validate();
}
//this is the method we want to prevent from running in case of error in validation
super.selectTab(tab);
}catch (ValidationException ex) {
//show alert or do nothing tab won't be changed
}
}
});
The ValidatingTab is my own extension to Tab:
public class ValidatingTab extends Tab {
public void validate() throws ValidationException {
//validation
}
}
This is the "clean part" of the trick. Now we need to place ValidatingTabPaneBehavior into TabPane.
First you need to copy (!) the whole com.sun.javafx.scene.control.skin.TabPaneSkin to the new class in order to change its constructor. It is quite long class, so here is only the part when I switch the Behavior class:
public class ValidationTabPaneSkin extends BehaviorSkinBase<TabPane, TabPaneBehavior> {
//copied private fields
public ValidationTabPaneSkin(TabPane tabPane) {
super(tabPane, new ValidationTabPaneBehavior(tabPane));
//the rest of the copied constructor
}
The last thing is to change the skin in your tabPane instance:
tabPane.setSkin(new ValidationTabPaneSkin(tabPane));

How to Cleanup a ViewModel in Mvvm Light?

I have a list of items that goes to another page, That page is hooked up to a view model. In the constructor of this view model I have code that grabs data from the server for that particular item.
What I found is that when I hit the back button and choose another item fromt hat list and it goes to the other page the constructor does not get hit.
I think it is because the VM is now created and thinks it does not need a new one. I am wondering how do I force a cleanup so that a fresh one is always grabbed when I select from my list?
I faced the same issue, that's how i solved it.
Have a BaseView class, override OnNavigatedTo
protected override void OnNavigatedTo(NavigationEventArgs e)
{
base.OnNavigatedTo(e);
if (NavigatedToCommand != null && NavigatedToCommand.CanExecute(null))
NavigatedToCommand.Execute(null);
}
add DependencyProperty.
public static readonly DependencyProperty NavigatedToCommandProperty =
DependencyProperty.Register("NavigatedToCommand", typeof(ICommand), typeof(BaseView), null);
public ICommand NavigatedToCommand
{
get { return (ICommand)GetValue(NavigatedToCommandProperty); }
set { SetValue(NavigatedToCommandProperty, value); }
}
On the necessary pages, add to xaml (and, of course, inherit BaseView )
NavigatedToCommand="{Binding OnNavigatedToCommand}"
In the ViewModel, make command itself
public RelayCommand OnNavigatedToCommand
{ get { return new RelayCommand(OnNavigatedTo); } }
and implement method you want to call to update list
public async void OnNavigatedTo()
{
var result = await myDataService.UpdateMyList();
if (result.Status == OK)
MyList = result.List;
}
So, now, every time you navigate to page with list, inside of overriden OnNavigatedTo(), a NavigatedToCommand would be executed, which would execute OnNavigatedToCommand (which you set in xaml), which would call OnNavigatedTo, which would update your list.
A bit messy, but MVVM :)
EDIT: What about cleanings, they can be done in OnNavigatedFrom(), which works the same. Or OnNavigatingFrom(), which also can be useful in some cases.

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