CODEWITHSUNDEEP
c++gtkgtk3glib
Patryk Cysarz
Patryk Cysarz

Reputation: 134

GTK+ 3.0 C++ passing GtkTextBuffer to function

I'm learning the GTK+ library and got some problem, when I try to load text from file to TextView.

// main.cpp
GtkWidget *textInput;
GtkTextBuffer *textBuffer;
[...]
//Create text input field
textInput = gtk_text_view_new();
gtk_box_pack_start(GTK_BOX (vbox), textInput, 1, 1, 0);
textBuffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW (textInput));

// Menu actions
g_signal_connect(G_OBJECT(openFile), "activate", G_CALLBACK(showOpenFileDialog), textBuffer);

When I try to change textBuffer in main.cpp, all goes well. But...

void showOpenFileDialog(GtkTextBuffer *buffer)
{
GtkWidget *openFileDialog;
openFileDialog = gtk_file_chooser_dialog_new("Open file", GTK_WINDOW(NULL), GTK_FILE_CHOOSER_ACTION_OPEN,GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL, GTK_STOCK_OPEN, GTK_RESPONSE_ACCEPT, NULL);
gtk_dialog_run(GTK_DIALOG(openFileDialog));

const gchar *filename = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(openFileDialog));

ifstream file(filename);
string line;
if(file.is_open())
{
    while(getline(file, line))
    {
        GtkTextIter endOfTextInput;
        gtk_text_buffer_get_end_iter(buffer, &endOfTextInput);
        gtk_text_buffer_insert(buffer, &endOfTextInput, line.c_str(), line.size());
    }
}

gtk_widget_destroy(openFileDialog);
}

With every line loaded from file, GTK outputs runtime errors to console:

(asdddd.exe:3872): Gtk-CRITICAL **: gtk_text_buffer_get_end_iter: assertion `GTK
_IS_TEXT_BUFFER (buffer)' failed

(asdddd.exe:3872): Gtk-CRITICAL **: gtk_text_buffer_insert: assertion `GTK_IS_TE
XT_BUFFER (buffer)' failed

I tried doing this:

GTK_TEXT_BUFFER(buffer)

But it just given me another error

(asdddd.exe:3872): GLib-GObject-WARNING **: invalid cast from `GtkMenuItem' to `
GtkTextBuffer'

Can anyone help me?

Upvotes: 0

Views: 549

Answers (2)

andlabs
andlabs

Reputation: 11578

The signature for GtkMenuItem::activate is

void signalHandler(GtkMenuItem *sender, gpointer user_data);

Your signal handler (in this case, showOpenFileDialog()) must have this signature. In your case, you're passing the text buffer into the g_signal_connect() line properly, but that gets assigned to the user_data argument (the GtkMenuItem itself, in this case openFile, is the sender).

It is unfortunate that there cannot be static type checking for GObject signals. I do not know if a static analysis tool exists that can help.

Upvotes: 1

drahnr
drahnr

Reputation: 6886

You need to use void showOpenFileDialog(GtkMenuItem *openFile, GtkTextBuffer *buffer) for the callback, since the first argument will be the caller, the second one the user_data you pass to g_signal_connect as last argument.

Upvotes: 0

Related Questions