I need to load select's options asynchronously (
through a service), using the Angular Material md-select component.
Actually, I use a click event to load data. It works but I need to click the select twice to show the options. That it's a problem.
The expected behavior is shown at this link (AngularJs Material)
The actual behavior is shown at this link.
Is Async options' loading supported by md-select?
The reason you need to click twice is because when you first click, there are no options in the select control and so it doesn't try and open the panel. Then your async method loads the options into the DOM and on the next click it will open.
In order to deal with this, you must always include at least one <mat-option> in your <mat-select>. You can add a disabled <mat-option> with a <mat-spinner> showing that the data is loading for example.
Here the most simple example of that. This is not the best approach... see below.
However, this still uses the click event which isn't the best approach. If you put the click event on the <mat-select> there are spots where you can click on the control but your click event wont trigger even though the dropdown panel still opens (places like the floating label area). You could put the click event on the <mat-form-field> but then there will be places where you can click and trigger the click event but the dropdown panel wont open (places like the hint/error text area). In both cases you lose keyboard support.
I would suggest using the <mat-select> openChanged event instead of a click event. This has its own quirks too but they are manageable.
Here is an example using the openChanged event. I also made the component more robust overall.
I also made a version that uses the placeholder element to show the spinner instead of using a disabled mat-option. This required View Encapsulation to be turned off.
Note: In my example, the service can return different data depending on the circumstances. To simulate this my fake service keeps track of how many requests you send it and changes the options returned accordingly. So I have to set the option list back to empty and clear the formControl's value every time the list is opened. I save the selected value before clearing the formControl so that if the service returns a list with the same item I can automatically reselect the value. If you only need to load the options once, then you would want to modify the code a bit to only load the options the first time the user opens the select.
I have a situation similar to the following simplified description:
A form with a TextBox (call it txtQty) in which a user can enter an integer. The event txtQty_Validate is used to validate the user input and force them to correct any errors before changing focus. This works great with all other controls on the form except for said txtQty. I assume that this is because the Cancel button on the form has the property CausesValidation necessarily set to false; thus when the user Tabs from txtQty to the Cancel button (whose TabIndex is next) it does not appropriately trigger the txtQty_Validation event.
My first instinct was to simply go to the txtQty_KeyPress event (which I am already using to make the RETURN key behave as TAB key) and capture the TAB key and temporarily toggle the CausesValidation property to allow the txtQty_Validation event to fire. However, it seems as though capturing the TAB key is not as easy as I had thought it would be.
Any suggestions? I assume that this cannot be the first time anybody creating a Form has come across such a situation.
Thanks
You could try this in the Cancel GotFocus event.
Dim b As Boolean
Call txtQty_Validate(b)
If b Then txtQty.SetFocus
Assuming you have something like this
Private Sub txtQty_Validate(Cancel As Boolean)
If Not IsNumeric(txtQty.Text) Then
Cancel = True
End If
End Sub
In my code I have bound the defaultProperty of a button to some other properties like so:
BooleanBinding isAddResourceButtonDefault
= resourceNameTextField.focusedProperty().or(
resourceTypeComboBox.focusedProperty()).or(
divisibleResourceCheckbox.focusedProperty().or(
maxInstancesTextField.focusedProperty()).or(
addResourceButton.focusedProperty()));
addResourceButton.defaultButtonProperty().bind(isAddResourceButtonDefault);
The problem is that the addResourceButton won't fire absolutely any events on pushing Enter - neither OnAction, nor OnKeyPressed.
The default property gets set just fine - I double checked (using output and ScenicView). ScenicView also doesn't show any events being fired upon hitting keys. Any ideas?
I believe TextFields (and other TextInputControls) process and consume key events that occur on them. So pressing Enter on a text field will not fire an action event on the default button (because the key event never reaches the Scene).
If you are just trying to fire the button's action event handler when enter is pressed in one of the text fields, just add the same event handler to the text fields. E.g.
EventHandler<ActionEvent> addResourceHandler = event -> {
System.out.println("Add resource");
// ...
};
addResourceButton.setOnAction(addResourceHandler);
resourceNameTextField.setOnAction(addResourceHandler);
maxInstancesTextField.setOnAction(addResourceHandler);
I want to create a dynamic action, that will set a value to an item on the page, when the value of another item (autocomplete text field) is set.
So the proccess goes like this:
Click on the autocomplete field
type some letters
choose one of the suggested values
I cannot find an event that will be executed when the selection of one of the suggested values happens. This way, I cannot see how I can read the value of the autocomplete field, once a suggested value is selected.
The change event doesn't fit my needs, it doesn't execute when one suggested value is selected.
I had the same problem, found this link: https://community.oracle.com/thread/2130716?tstart=0 and modified my dynamic action as follows to get the desired behaviour:
Event = Custom
Custom Event = result
From the link:
the problem seems to be the default behavior of the browser. When you
enter some text into the autocomplete and the list is displayed, the
focus is still in the text field. Also if you use the keyboard cursors
to pick an entry the focus will still be in the textfield. That's why
the change event of the textfield doesn't fire. It only fires if you
leave the field.
On the other side if you pick an entry with the mouse, the browser
will remove the focus from the text field for a moment (before the
JavaScript code puts the focus back), because you clicked outside of
the field. But that's enough so that the browser fires the change
event.
I had a look into documentation of the underlaying jQuery Autocomplete
widget
(http://bassistance.de/jquery-plugins/jquery-plugin-autocomplete/) and
there is actually an event called "result" which can be captures if an
entry is selected from the drop down list.
Try "Lose Focus" as event. It will trigger your dynamic action when you leave the autocomplete field, i.e. your curosr is moved to another field.
This probably depends on the APEX version you are using.
In case of 18.2, because the underlying component is based on Oracle JET's "inputSearch" component, you need to use following configure to capture the select change event for text with autocomplete:
event: Custom
custom event: ojupdate
Reference:
https://docs.oracle.com/cd/E87657_01/jet/reference-jet/oj.ojInputSearch.html#event:optionChange
I turned on the browser console, then turned ApEx Developer toolbar debug, and found that, on the contrary, the "Change" event does fire upon user clicking with the mouse on one of the selections. However if the user uses keyboard (type a few letters to narrow the list down, then use down arrow key to arrive at desired value, then press enter) then the Change event does not fire, just as you say.
Moreover: even when you do get the value sent back via mouse-click initiated Change event, the value isn't the autocomplete's complete and valid value, but instead the possibly partial and wrong-case value just as typed by the user. I.e., the the change event's submission of the value precedes the autocomplete's substitution.
The answer that #VincentDeelen gave is the best alternative that I can see, although it doesn't quite give that "instantantenous synchronicity" feel. You could maybe use the "Key Down" event, but be careful with that. You could get a really excessive amount of web and db traffic as each and every keystroke (including corrections) results in another firing of the dynamic action.
Testing environment: ApEx 4.2.3 with Chrome 33 as well as IE 9.
p.s. This might be worth a mention to the ApEx development team as well.
It's not really ideal, but you could use onfocus(). I'm looking for the same thing you are, I think, a custom event that fires when the selection of a suggested value happens. I haven't found it yet though and that is my work-around for now. It will run whatever function you've created for this initially with no value, but once the selection is made it will return focus and run the function again with the right value. Like I said, not ideal but it works.
Jeffrey Kemp is right. You can set it up through a dynamic action using the custom event, result. You can also register it on page load using document.getElementById("{id}").addEventListener("result", {function}); or $("#{id}").result( function( event, data, formatted ) { //something here });.
Oracle apex 19 now added a "component event" when you create a dynamic action called "Update [Text Field with autocomplete]" - this action is fired when you select a value from the list, but not when you leave the field (similar to adding the custom event "ojupdate").
how i can get (if)any text is selected in textbox and i want to get it in any variable of javascript.... specifically for Mozilla firefox...?
the above description is not enough so let me give completely the definition.. My Extension of firefox is an Extension that double clicks any word from the webpage and finds its possible meaning from database... so user can even write anything in Textbox and double click the same for finding its meaning.. so please do suggest any way to complete selection from textbox's selected text....? in addition i am already using dblclick event handler so dont suggest that solution.... Also the problem is that the web page can be any site's webpage so even the textarea or any control is specific tho that page how could i slice the text from it than ...Thanxx in advance....
You can use document.getSelection() which returns a selection object containing the currently highlighted text in the document. However, calling it at the right time can be tricky. You can't do it from an onclick handler on a button, for instance, because by the time the onclick handler fires, the selection's focus has been removed from the text and moved to the button.
Use the selectionStart and selectionEnd properties e.g.
var selectedText = textbox.value.slice(textbox.selectionStart, textbox.selectionEnd);