[Interest] Myanmar-QWERTY crashes OS X application

[Timothy W. Grove]

Let's see if the formatting is any better this time...

Below is my progress thus far. I've created a simple app with two 
QPlainTextEdit's. The only thing else it does is to print out the name 
of the keyboard input source associated with a QPlainTextEdit when you 
click into it. I'm unsure how to translate the python code for changing 
the keyboard into C++ but I've added comments to the 
"MainWindow::changeKeyboard" method below to show my approach in python. 
Any help or suggestions would be most welcome.

Best regards,
Tim

mainwindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QPlainTextEdit>


class MainWindow : public QMainWindow

{
     Q_OBJECT

public:
     MainWindow();
     void changeKeyboard(QVariant keyboard);

protected:
     bool eventFilter(QObject *obj, QEvent *event);

private:
     QWidget *mainWidget;
     QPlainTextEdit *textEdit1;
     QPlainTextEdit *textEdit2;

};

#endif // MAINWINDOW_H


mainwindow.cpp:

#include <QWidget>
#include <QVBoxLayout>
#include <QPlainTextEdit>
#include <QObject>
#include <QEvent>
#include <QDebug>
#include "mainwindow.h"
#include "Windows.h"

MainWindow::MainWindow()
{
     mainWidget = new QWidget;
     setCentralWidget(mainWidget);

     QVBoxLayout *layout = new QVBoxLayout;
     textEdit1 = new QPlainTextEdit;
     textEdit1->setProperty("keyboard", 0x00000809); // British(Windows)
     textEdit2 = new QPlainTextEdit;
     textEdit2->setProperty("keyboard", 0x00010C00); // Myanmar(Windows)
     layout->addWidget(textEdit1);
     layout->addWidget(textEdit2);
     mainWidget->setLayout(layout);

     textEdit1->installEventFilter(this);
     textEdit2->installEventFilter(this);
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
   if (obj == textEdit1 || obj == textEdit2) {
       if (event->type() == QEvent::FocusIn) {
           changeKeyboard(obj->property("keyboard"));
       }
   }
   return QMainWindow::eventFilter(obj, event);
}

void MainWindow::changeKeyboard(QVariant keyboard)
{
     qDebug() << keyboard.toString();

     /* The following is how I did this in Python but I am unsure how to 
translate this into C++.
        A different approach in C++ would be okay, but it needs to be an 
approach I can translate
        back into Python/PyQt.

     from Cocoa import NSTextInputContext //This line goes at top of 
page with any other import statements
     ic = NSTextInputContext.currentInputContext()
     if not ic:
         ic = NSTextInputContext.new()
     ic.setValue_forKey_(keyboard.toString(), 'selectedKeyboardInputSource')
     */

}

On 19/08/2016 16:48, timur.kristof at gmail.com wrote:
> Can you create a simple example app without Python, to see if it really is Qt's fault?
>
> (Just create an app with Qt Creator and run it. As far as I understand, you use QWidgets, right? If so, create an empty QWitgets project, run and see how it goes.)
>
> On Fri Aug 19 13:33:58 2016 GMT+0200, Timothy W. Grove wrote:
>> Changing the keyboard input source on OS X back and forth between
>> 'British' and 'Myanmar-QWERTY' crashes my PyQt v5.7 application after
>> about three changes, usually corrupting an attached sqlite database as
>> well. 'Myanmar-QWERTY' is the only input source that I'm having trouble
>> with; all others that I've tested so far appear okay. The windows
>> version of the application also seems okay. My application is fairly
>> complex, but I'm seeing this issue even with an absolute minimal app
>> containing only one window. I'm not certain if the issue is with PyQt or
>> Qt or the input source itself, but it doesn't appear to be with python
>> as a Tkinter app worked okay.
>>
>> Any answers would be great, but if anyone could suggest where to find a
>> solution that would also be helpful. This is a pretty obscure bug, but
>> finding a solution or work-around is important to the application I'm
>> developing. Thank you.
>>
>> Best regards,
>> Timothy Grove
>>
>>
>> Test program:
>>
>> #!/usr/bin/env python3
>> # -*- coding: utf-8 -*-
>>
>> import sys
>> from PyQt5.QtWidgets import QMainWindow
>> from PyQt5.QtWidgets import QTextEdit
>> from PyQt5.QtWidgets import QApplication
>>
>> class MainWindow(QMainWindow):
>>       def __init__(self, parent=None):
>>           super(MainWindow, self).__init__(parent)
>>
>>           text = QTextEdit()
>>           self.setCentralWidget(text)
>>
>> if __name__ == "__main__":
>>       app = QApplication(sys.argv)
>>
>>       mw = MainWindow()
>>       mw.show()
>>
>>       sys.exit(app.exec_())
>>
>> _______________________________________________
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>> Interest at qt-project.org
>> http://lists.qt-project.org/mailman/listinfo/interest
>>