Statusbar (JavaScript)

This statusbar keeps track of how many times you've clicked a button. Applications like gedit use statusbars to display information at a glance, and show notifications without interrupting the user.

Messages pushed to a statusbar go on top of its stack, and can be popped off to show the next-most recent one. You can also clear away every message of a specific type all at once. This sample application demonstrates these functions.

Libraries to import

These are the libraries we need to import for this application to run. Remember that the line which tells GNOME that we're using Gjs always needs to go at the start.

Creating the application window

All the code for this sample goes in the StatusbarExample class. The above code creates a Gtk.Application for our widgets and window to go in.

The _buildUI function is where we put all the code to create the application's user interface. The first step is creating a new Gtk.ApplicationWindow to put all our widgets into. The next step is to create a vertically-oriented Gtk.Paned interface, to divide the window up into two sections. This way the statusbar looks like those used in other applications, and it stays at the bottom of the window, even if the user resizes it.

Creating the buttons

This code creates the three Gtk.Buttons we'll use to push a new message to the statusbar, pop the last one off, and clear all existing messages. The "back" and "clear" buttons are stock buttons, which are automatically translated into any language GNOME supports.

This code creates the Gtk.Grid that we'll use to organize the buttons, and attaches the buttons to it in order. It then creates a Gtk.Frame which will take up most of the window and has a large amount of padding around the buttons, and adds the Grid to the Frame. Note that we still need to put the Frame into the Paned interface, and then add it to the ApplicationWindow.

Creating the statusbar

Here we create the Gtk.Statusbar, and push a message to it to start off with. Then we give it its own narrow frame at the bottom of the window.

Every message needs to have a context id, which is an integer value you can get from the statusbar with the get_context_id() function. Its only parameter is the string value you use to describe that particular context id. Normally, you'll get a new context id for different kinds of messages, so that you can use the remove() function to remove a specific message and not just the most recent one on the stack. This is a simple example with only one kind of message, though, so we're just using one for everything.

We use the push() function to push a new message onto the stack. Its first parameter is the context id, and its second is the message.

This code finishes up creating the window, by packing the frames into the pane, adding it to the window, and telling the window to show all child widgets.

Functions for interacting with the statusbar

 0 ) {
            this.Clicks--;
            this._statusbar.pop (this.ContextID);
        };

    },



    _clear: function () {

        // Reset the number of clicks
        this.Clicks = 0;

        // Wipe out all the messages pushed to the statusbar
        this._statusbar.remove_all (this.ContextID);

        // Reset the statusbar's message
        this._statusbar.push (this.ContextID, "Number of clicks: " + this.Clicks);

    }

});
]]>

Here we have functions which demonstrate pushing a message onto the stack, popping the top one off of it, and clearing all messages of a particular context id. The pop() function just takes one parameter, which is the context id for the type of message you want to pop off the most recent one of. The remove_all() function works the same way, except it removes all messages of that type from the stack.

Finally, we create a new instance of the finished StatusbarExample class, and set the application running.

Complete code sample

In-depth documentation

Gtk.Application

Gtk.ApplicationWindow

Gtk.Button

Gtk.Frame

Gtk.Paned

Gtk.Statusbar