How to intercept system keypress in a GTK application - gtk

I am working on a Vala GTK application that starts minimized by default and I want to bind a specific keyword shortcut to bring the minimized window to the front.
I am able to handle Keyboard events using Accelerators when the app is focus ed, but I am unable to intercept any key press from the system when the app is minimized.
How can I make the app listen to system keyboard events so I can detect the key press accordingly?
Thank you.

I took a look at the source for Ideogram to see how it registers Super-e as a hot-key. It looks to be basically the following, including first checking that a custom hot-key has not already been registered for the application.
// These constants are set at class level.
public const string SHORTCUT = "<Super>e";
public const string ID = "com.github.cassidyjames.ideogram";
// Set shortcut within activate method.
CustomShortcutSettings.init ();
bool has_shortcut = false;
foreach (var shortcut in CustomShortcutSettings.list_custom_shortcuts ()) {
if (shortcut.command == ID) {
has_shortcut = true;
return;
}
}
if (!has_shortcut) {
var shortcut = CustomShortcutSettings.create_shortcut ();
if (shortcut != null) {
CustomShortcutSettings.edit_shortcut (shortcut, SHORTCUT);
CustomShortcutSettings.edit_command (shortcut, ID);
}
}
It uses a CustomShortcutSettings class included in its source to handle the reading and writing to the system settings. The class originated in another application called Clipped.

Related

MAUI Text Entry on Complete not Working - Possible Work around?

I'm trying to use text entry on maui to fire an event when completed. I have set the "Completed" event to a handler and it works correctly on windows. But on Android I have no joy, the event just isn't firing.
I realise there is a bug in Maui which is preventing this. But it looks like the problem was discovered in August? It's a fairly basic thing, well at least it appears to be on the face of things.
What is the best work around for this? The only thing I can think is by using the textchanged event instead of completed. This works correctly, but then i have to bodge it by doing this sort of thing:
if (entry1.Text.EndsWith("#"))
{
//Then string is complete, so need to fire correct event
System.Diagnostics.Debug.WriteLine("Complete String Detected");
}
This works and I can use it since I'm awaiting for input from a barcode scanner, so I can set the last terminating character to whatever I want. In this case I set it to a #. I can't figure out a way to detect the return key being pressed.
Thanks
Andrew
There is a similar issue on the github about the Entry.Completed and Entry.ReturnCommand not executed.
This comment shows the cause and the workaround about this problem.
detect the return key being pressed
In addition, I can't understand the problem. I have created a sample to test. The Entry.Completed event will call when I pressed the enter key. I don't kown the return key you mentioned is what. But you can use the IOnKeyListener for the android to detect any key being pressed.
Create a Listener class in the /Platform/Android:
public class MyKeyListener : Java.Lang.Object, IOnKeyListener
{
public bool OnKey(global::Android.Views.View v, [GeneratedEnum] Keycode keyCode, KeyEvent e)
{
var edittext = v as AppCompatEditText;
if (keyCode == Keycode.Enter && e.Action == KeyEventActions.Down )
//I used the Entry key as the example, you can use any other key you want to replace it.
{
edittext.ClearFocus();
edittext.SetBackgroundColor(Color.GreenYellow);
return true;
}
return false;
}
And in the page.xml:
<Entry Completed="Entry_Completed" x:Name="entry"/>
Set the listener to the entry by overriding the OnHandlerChanged() in the page.cs:
protected override void OnHandlerChanged()
      {
            base.OnHandlerChanged();
#if ANDROID
(entry.Handler.PlatformView as AndroidX.AppCompat.Widget.AppCompatEditText).SetOnKeyListener(new MauiAppTest.Platforms.Android.MyKeyListener());
#endif
}
You can also set the listener with the handler. Finally, you can try both the method above and the workaround in the issue on the github.

Eclipse RCP: Can I remove Orphaned Perspectives from the Perspective Bar?

I'm developing an RCP that has two product versions, a core app and one with some extensions. If a user opens the core app after having opened the extended app in the same workspace, eclipse detects a perspective used only in the extended app and makes a local copy of it, so it shows up in the perspective toolbar as an orphaned extension.
I created an activity to hide the extended app perspective when running the core app. That hides it from the perspective menu and the perspective shortcut menu, but it doesn't remove it from the perspective toolbar.I also tried detecting orphaned perspectives from the active page of the active workbench window (by looking for angle brackets in the label) and removing them with PlatformUI.getWorkbench().getPerspectiveRegistry().deletePerspective(perspective), but this doesn't affect the perspective toolbar either. The perspective I'm removing is not present in the core app.
Is there a way I can access the perspective toolbar programmatically so I can remove any orphaned perspectives? Or any other approach tha would work?
I thought a good solution would be creating a custom perspective switcher, but that path was blocked by an eclipse bug. There is a suggested workaround, but it did not work for me. I created a custom perspective switcher toolbar, but I could find no way to make it update when perspectives are opened or activated. My attempts are documented here.
I removed the orphan perspectives in a workspace shutdown hook, but for some reason an NPE is thrown by the E4 workbench (LazyStackRenderer line 238) when I select a perspective in the switcher that was opened but not selected when I launched the app.
I got it to work as desired by closing all open perspectives on shutdown, after storing their IDs in a preference value, and then opening them again when the app is launched in the WorkbenchWindowAdvisor. It's a bit of a hack, but it's the only way I could find to avoid the E4 workbench NPE, which also prevents setting the perspective from the toolbar until it's closed and re-opened from the Window menu.
Here's my code.
...
IWorkbench workbench = ...
static final String PERPSECTIVE_ID_1 = ...
static fnal String PERSPECTIVE_ID_2 = ...
static final String PREFERENCE_KEY = ...
workbench.addWorkbenchListener( new IWorkbenchListener() {
public boolean preShutdown( IWorkbench workbench, boolean forced ) {
IPerspectiveDescriptor[] openPerspectives = page.getOpenPerspectives();
page.closeAllPerspectives(false, false);
StringBuilder sb = new StringBuilder();
String delim = "";
for (IPerspectiveDescriptor persp : openPerspectives) {
if (!persp.getId().equals(PERSPECTIVE_ID_1) && !persp.getId().equals(PERSPECTIVE_ID_2) {
sb.append(delim + persp.getId());
delim = ";";
}
}
getPreferenceStore().setValue(PREF_KEY, sb.toString());
return true;
}
public void postShutdown( IWorkbench workbench ) {
}
});
class MyWorkbenchWindowAdvisor extends WorkbenchWindowAdvisor {
static final String PRODUCT_ID_1 = ...
static final String PRODUCT_ID_2 = ...
static final String PREFERENCE_KEY = ...
...
#Override
public void postWindowOpen() {
IWorkbenchPage page = getWindowConfigurer().getWindow().getActivePage();
String savedOpenPerspectiveStr = getPreferenceStore().getString(PREFERENCE_KEY);
if (!"".equals(savedOpenPerspectiveStr)) {
List<IPerspectiveDescriptor> openPerspectives = new ArrayList<IPerspectiveDescriptor>();
String[] perspectiveIds = savedOpenPerspectiveStr.split(";");
if (perspectiveIds.length == 0) {
openPerspectives.add(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(savedOpenPerspectiveStr));
} else {
for (String id : perspectiveIds) {
openPerspectives.add(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(id));
}
}
//successively setting perspectives causes them to appear in the perspective switcher toolbar
for (IPerspectiveDescriptor persp : openPerspectives) {
page.setPerspective(persp);
}
}
//now we set the appropriate perspective
if (Platform.getProduct().getId().equals(PRODUCT_ID_1)) {
page.setPerspective(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(PERSPECTIVE_ID_1));
} else if (Platform.getProduct().getId().equals(PRODUCT_ID_2)) {
page.setPerspective(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(PERSPECTIVE_ID_2));
}
}
...
}

Eclipse PDE: Programmatically detect opened dialog and close it

On Eclipse Luna, I select a server and click the Start button on Servers view, then the server (for example Tomcat8) will get started. If something is wrong during the start-up process, a dialog will be populated to display the error messages (for example time-out). The dialog is modeless in this test case.
Now I need to start the server programmatically from a plugin. In case that errors occur, how could I programmatically detect that a dialog has been opened and how to close it?
You could use the Display.addFilter method to listen for all SWT.Activate events which will tell you about all Shells (and other things) being activated. You can then detect the shells you want to close.
Something like:
Display.getDefault().addFilter(SWT.Activate, new Listener()
{
#Override
public void handleEvent(final Event event)
{
// Is this a Shell being activated?
if (event.widget instanceof Shell)
{
final Shell shell = (Shell)event.widget;
// Look at the shell title to see if it is the one we want
if ("About".equals(shell.getText()))
{
// Close the shell after it has finished initializing
Display.getDefault().asyncExec(new Runnable()
{
#Override
public void run()
{
shell.close();
}
});
}
}
}
});
which closes a dialog called 'About'.
In more recent versions of Java the above can be simplified to:
Display.getDefault().addFilter(SWT.Activate, event ->
{
// Is this a Shell being activated?
if (event.widget instanceof Shell shell)
{
// Look at the shell title to see if it is the one we want
if ("About".equals(shell.getText()))
{
// Close the shell after it has finished initializing
Display.getDefault().asyncExec(shell::close);
}
}
});
This uses Java 8 lambdas and method references and Java 16 instanceof type patterns.

Cancel a close event

I have an editor in Eclipse. When the user chooses to close it, a dialog shall appear with several options. One of them is "Cancel" and should cancel the close event. How can I do that?
The partial code I have so far:
...
IEditorPart openEditor = page.openEditor(input, CS_STRINGEDITOR_ID);
openEditor.getEditorSite().getPage()
.addPartListener(new IPartListener() {
public void partOpened(IWorkbenchPart part) {}
public void partDeactivated(IWorkbenchPart part) {}
public void partClosed(IWorkbenchPart part) {
Shell sh = new Shell(cv.getViewSite().getShell());
// My MessageDialog with the options, one being "cancel"
CloseDialog closeDialog = new CloseDialog(sh);
closeDialog.open();
int returnCode = closeDialog.getReturnCode();
switch (returnCode) {
case CloseDialog.CANCEL_ID:
// Abort the close event and keep the editor alive
break;
}
}
This thread points out there is no closing event per se.
Eclipse provides mostly post-activite events, i.e. on IPartListener2, partClosed(*) is a
post-closing event.
You can provide your own dialog on close, but it will only be shown if the
editor is dirty at the time it is closed. See ISaveablePart2.promptToSaveOnClose()
(as presented in the Prevent that a RCP Editor is closed)
However, note that implementing ISaveablePart2 may lead to many dialogs being opened when you close multiple editors.

.Net CF Prevent Overzealous, Impatient Clicking (while screen is redrawing)

.Net Compact Framework
Scenario: User is on a screen. Device can't finds a printer and asks the user if they want to try again. If they click "No", the current screen is closed and they are returned to the parent menu screen. If they click the "No" button multiple times, the first click will be used by the No button and the next click will take effect once the screen has completed redrawing. (In effect clicking a menu item which then takes the user to another screen.)
I don't see a good place to put a wait cursor...there isn't much happening when the user clicks "No" except a form closing. But the CF framework is slow to redraw the screen.
Any ideas?
you can skip pending clicks by clearing the windows message queue with
Application.DoEvents();
We use the following custom Event class to solve your problem (preventing multiple clicks and showing a wait cursor if necessary):
using System;
using System.Windows.Forms;
public sealed class Event {
bool forwarding;
public event EventHandler Action;
void Forward (object o, EventArgs a) {
if ((Action != null) && (!forwarding)) {
forwarding = true;
Cursor cursor = Cursor.Current;
try {
Cursor.Current = Cursors.WaitCursor;
Action(o, a);
} finally {
Cursor.Current = cursor;
Application.DoEvents();
forwarding = false;
}
}
}
public EventHandler Handler {
get {
return new EventHandler(Forward);
}
}
}
You can verify that it works with the following example (Console outputs click only if HandleClick has terminated):
using System;
using System.Threading;
using System.Windows.Forms;
class Program {
static void HandleClick (object o, EventArgs a) {
Console.WriteLine("Click");
Thread.Sleep(1000);
}
static void Main () {
Form f = new Form();
Button b = new Button();
//b.Click += new EventHandler(HandleClick);
Event e = new Event();
e.Action += new EventHandler(HandleClick);
b.Click += e.Handler;
f.Controls.Add(b);
Application.Run(f);
}
}
To reproduce your problem change the above code as follows (Console outputs all clicks, with a delay):
b.Click += new EventHandler(HandleClick);
//Event e = new Event();
//e.Action += new EventHandler(HandleClick);
//b.Click += e.Handler;
The Event class can be used for every control exposing EventHandler events (Button, MenuItem, ListView, ...).
Regards,
tamberg
Random thoughts:
Disable the some of the controls on the parent dialog while a modal dialog is up. I do not believe that you can disable the entire form since it is the parent of the modal dialog.
Alternatively I would suggest using a Transparent control to catch the clicks but transparency is not supported on CF.
How many controls are on the parent dialog? I have not found CF.Net that slow in updating. Is there any chance that the dialog is overloaded and could be custom drawn faster that with sub controls?
override the DialogResult property and the Dispose method of the class to handle adding/remvoing a wait cursor.