When I am populating data into GTK widgets, I often encounter this problem: when I immediately scroll the GTK widget to the bottom or try to access the widget's data right after populating it, it cannot scroll to the very bottom in time, nor can it retrieve the latest data. This is because I populate the data too quickly, and the GTK widget has not yet updated to display that data. As a result, operations cannot be performed on the new data.

Therefore, some processing needs to be done after quickly populating the data.

Situation 1

The use of GtkEntry: immediately retrieving data after filling it can easily cause errors

gtk_entry_set_text(GTK_ENTRY(g_custompwEntry), "xxx");
//After setting the string, immediately retrieving it may return the previous content.
const char *text = gtk_entry_get_text(GTK_ENTRY(g_custompwEntry));

This method is to define a custom callback function to update g_custompwEntry, and use the g_idle_add function to dispatch this function to the main thread. The main thread will handle it at an appropriate time.

static gboolean refresh_custompw_entry_idle(gpointer data){
    const char *text = gtk_entry_get_text(GTK_ENTRY(g_custompwEntry));
    ...

    return false;
}
...
gtk_entry_set_text(GTK_ENTRY(g_custompwEntry), "xxx");
g_idle_add(refresh_custompw_entry_idle,  user_data);

Situation 2

Scrolling in GtkScrolledWindow. If a GtkVBox is added inside a GtkScrolledWindow, and the VBox adds new content causing its length to expand, you will need to immediately update the GtkScrolledWindow to scroll to the bottom. If you call the function to scroll to the bottom immediately, you will find it doesn’t succeed because the new content hasn’t been displayed yet, making the scroll ineffective.

The solution is to add a one-time timer, for example, automatically scroll after 100ms when new content is added. Alternatively, you can use a g_idle_add callback function to handle the scroll when GTK is idle, which can solve the problem.

static gboolean scroll_to_bottom_callback(gpointer data) {
    GtkAdjustment *vadjustment = GTK_ADJUSTMENT(data);
    double max_value = gtk_adjustment_get_upper(vadjustment) - gtk_adjustment_get_page_size(vadjustment);
    gtk_adjustment_set_value(vadjustment, max_value);
    return G_SOURCE_REMOVE;
}

...
//New content added
gtk_box_pack_start(GTK_BOX(g_cardListBox),widgetTest,false,false,5);
//Automatic scrolling
GtkAdjustment *vadjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(g_cardListScrolledWindow));
g_idle_add(scroll_to_bottom_callback, vadjustment);

Situation 3

GtkTextView also has this problem. After I fill text into GtkTextView, it works properly if it is continuously updating and scrolling. But if a modal window pops up immediately after filling in the final text, the last text cannot be displayed. It also won't scroll to the end.

static void roll_text_view_to_end(GtkTextView *textView){
    
    GtkTextBuffer* textBuffer = gtk_text_view_get_buffer(textView);
    GtkTextIter iter;
    gtk_text_buffer_get_end_iter(textBuffer,&iter);
    gtk_text_view_scroll_to_iter(GTK_TEXT_VIEW(textView), &iter, 0.0, TRUE, 0.0, 1.0);
}

...
//If this is the last batch of information, it cannot be displayed, nor can you scroll to the end.
fill_text_info();
roll_text_view_to_end(GTK_TEXT_VIEW(g_scanTextView));
//Popup modal window blocks execution
GtkWidget *dialog;
        dialog = gtk_message_dialog_new(NULL,
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_INFO,
            GTK_BUTTONS_OK,
            "info");
gtk_window_set_title(GTK_WINDOW(dialog), "Information");
gtk_dialog_run(GTK_DIALOG(dialog));
gtk_widget_destroy(dialog);

There is a simple way, which is to forcibly update the GUI after adding information.

fill_text_info();
//Force update the GUI so that after adding text it can be displayed immediately, and subsequent scrolling will also proceed successfully.
while(gtk_events_pending()){
    gtk_main_iteration();
}
roll_text_view_to_end(GTK_TEXT_VIEW(g_scanTextView));