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# Using Qt Standard Dialogs

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We start by using two of the Qt Standard Dialogs: QFileDialog and QMessageBox. Both of these classes provide useful static convenience functions.

QFileDialog::getOpenFileName() | replacement for the Open dialog
QFileDialog::getSaveFileName() | replacement for the Save As dialog
QMessageBox::information() | replacement for Page Delete dialog
QMessageBox::warning() | replacement for IO Error dialog.

Each of these functions takes a QWidget *parent argument. If we pass zero as the parent argument, then we will have dialogs that are centered on the screen, instead of being centered over our main window. We can have QMotifWidget create our `XmMainWindow`, and we can then use this class as the parent for both Motif dialogs and Qt dialogs.

We need to include the appropriate headers for QMotifWidget and QFileDialog in `todo.cpp`.

Next, we make a few modifications to how the application is initialized. We could initialize Xt/Motif and create the `XtAppContext` ourselves, but QMotif can do this for us. We also let QApplication open the connection to the X server. Next, we create a QMotifWidget, passing `xmMainWindowWidgetClass` as the widgetclass argument. We can now use the QMotifWidget::motifWidget() function to access the Motif widget. The shell widget is created automatically by QMotifWidget. We use `XtParent()` to access it. The top-level window is now a QMotifWidget, which means we can use it as the parent for the Qt Standard Dialogs.

## Replacing the Open and Save As Dialogs

First, we completely remove all use of the existing Motif file selection dialog. We remove the `Xm/FileSB.h` include, the global `file_dialog` variable, and the code to create the dialog. We also remove the `PresentFDialog()` callback function. None of this code is needed to use QFileDialog.

After removing the `PresentFDialog()` callback function, we need to make Open and Save As popup-menu callbacks call the `Open()` and `Save()` functions.

First we must change the declaration of these two functions.

We also change the arguments to the callbacks. We pass the top-level QMotifWidget as the `client_data` to these functions, since we will be using it as the parent for the QFileDialog.

        ...

Next, we modify the `Save()` function to use QFileDialog::getSaveFileName().

... and the `Open()` function to use QFileDialog::getOpenFileName().

After we build the project, the application runs and operates as expected. The difference is that the Open and Save As dialogs now use QFileDialog.

## Replacing the Page Delete and IO Error Dialogs

The Page Delete dialog is created and used in `actions.c`. We need to migrate this file to C++. We rename it to `actions.cpp`, modify the project file and regenerate the `Makefile`.

The changes required to make `actions.cpp` compile are minimal. We need to wrap more C header files and global variables in an `extern "C"` block.

We need to forward declare the `NewPage()`, `DeletePage()`, `EditPage()` and `SaveIt()` functions so that the compiler generates the correct symbols for these functions.

We need to fix a single invalid pointer cast.

And we need to change the variable named new to newstr in the `Trim()` function.

We can now change the `DeletePage()` function to use QMessageBox::information().

First, we need to make sure we include the proper header for QMessageBox.

The code for `DeletePage()` looks like this:

At this point in the code, the page should be deleted. The code to do this is in the `DoDeletePage()` function. We move the contents of `DoDeletePage()` to this point and remove the `DoDeletePage()` function completely.

Next, we change `todo.cpp` to pass the top-level QMotifWidget as the `client_data` tot he `DeletePage()` function.

The IO Error dialog is created and used in `io.c`. We need to migrate this file to C++. We rename it to `io.cpp`, modify the project file and regenerate the `Makefile`.

The changes required to make `io.cpp` compile are minimal. We need to wrap more C header files and global variables in an `extern "C"` block.

We need to forward declare the `ReadDB()` and `SaveDB()` functions so that the compiler generates the correct symbols for these functions.

The `ParseNewLines()` function needs to be converted to proper C++.

The `PrintWithNewLines()` function also needs to be converted to proper C++.

We can now change the `ReadDB()` and `SaveDB()` functions to use QMessageBox::warning().

First, we need to make sure we include the proper header for QMessageBox.

The code for `ReadDB()` looks like this:

        ...

The code for `SaveDB()` looks like this:

        ...

After we build the project, the application runs and operates as expected. The difference is that the Page Delete and IO Error dialogs now use QMessageBox.

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