Context

If you are already familiar with the structure of Qt 5 code, feel free to jump to the next section.

In Qt 4, the whole source code is in the same git repository. The traditional widgets derived from QWidget are part of the QtGui module and represent a central piece for the GUI application development.

In Qt 5, things changed. Qt code were splitted in many repositories which group Qt libraries depending on their functionalities.
Examples of repositories are qtbase, qtdeclarative, qtjsbackend, qtxmlpatterns, qtsvg, qttools, etc.
As you may know, QtQuick 2 became a first class citizen in Qt 5, which means qtdeclarative is one of the main repositories, house of QtQuick and QtQml classes.

But, there are classes that provide the base for QtQuick 2 work properly – they are part of the qtbase repo. There you find QtCore,
QtGui, QtNetwork, QtOpenGL, QtPlatformSupport, QtXml, QtWidgets, etc.

Wait: What’s the difference between QtGui and QtWidgets?

As part of the changes of Qt 5, QtGui is now focused in the basic infrastructure for GUI work on different platforms. For example, it is the place for the platform abstraction layer, window management, image handling, etc.

QtWidgets, as you can conclude based on its name, contains the children of QWidget: QPushButton, QSpinBox, QMainWindow, etc. Also, there are non-widgets classes in QtWidgets, some of them because they are internally too coupled to QWidget classes.

Origins

In this thread it was mentioned the case of QUndoStack, QUndoCommand that are in QtWidgets but can be useful in other contexts where developers do not want to link against QtWidgets just because of this kind of helper classes.
Later, in the change 15857 (with the help of ogoffart), we discussed about moving QUndo* out of QtWidgets. First, we moved these classes to QtGui what as not considered correct given the new motivation of this lib. Then, another idea was to move the classes to a new lib, inside qtbase. It was not considered ideal and the decision was to create a separated repo for these classes, leaving QtWidgets untouched (since the Qt community do not want to introduce new bugs in this lib).

Current status

We set a wiki page where it is possible to check the classes made available out of QtWidgets. Also, there are instructions about where to download the source code, build, test and contact us.

Besides moving classes out of QtWidgets, some prototypes of convenience APIs were created for QtQuick 2 developers and we are very interested in receiving feedback about them. It’s worth mentioning the QML API for UndoStack and the CompletionModel which is based on the internals of QCompleter and was made available in a QML friendly way.

The following example shows a possible use case for the CompletionModel. Improving the models supported by sourceModel is part of the ToDo list. The ListView is going to show the updated list that currently satisfies what is written in the TextInput.

TextInput {
    id: input
}

CompletionModel {
    id: completionModel
    sourceModel: ["Ascension Island", "Andorra", "Afghanistan"]
    completionPrefix: input.text
    caseSensitivity: Qt.CaseInsensitive
}

ListView {
    model: completionModel
    delegate: Text { text: modelData }
}

The two examples bellow show the UndoStack and two items that represent commands. The idea of UndoPropertyCommand is to enable track the changes of some properties. In the example, we are going to track x and y when myRect is moved.

UndoStack {
    id: stack
    undoLimit: 5
}

UndoPropertyCommand {
    id: moveCommand
    properties: ["x", "y"]
}

Rectangle {
    id: myRect

    (...)

    MouseArea {
        (...)
        drag.target: parent
        onPressed: stack.push(moveCommand, myRect);
    }
}

UndoCommand is another element used to represent commands. The difference here is that it allows the customization of the actions onUndo and onRedo the command.

UndoCommand {
    id: aCommand

    onUndo: doAThing(target);
    onRedo: undoAThing(target);
}

Button {
    onClicked: stack.push(aCommand, target);
}

Future

Maybe one day this playground project gets promoted and become a Qt Add-on, but there is no expectation it will happen before 5.0. In the meanwhile, there is a ToDo list with some topics we consider important to handle, like better examples, more tests, docs, etc.

We are looking forward receiving more opinions about this work and, as always, contributors are welcome!

Then, after the end of this project, I finally managed to contribute to Qt5! :-)

Also, in the end of the last year some coworkers started a kind of pet project: It’s called Iceberg, a fork of the Icecream Monitor.

“Why a fork?” Here we use icecream for distributed compilation, many colleagues used to complain about icemon depending on kdelibs. In fact, the code did not use the additional features compared to the equivalent Qt classes. Then, after hugopl started the project, we fixed some issues and added new stuff. The code is here.

I am writing another post to introduce one of our current research projects, which is also part of the proposal I sent to Akademy 2012.

We are in Berlin, attending the Qt Contributor’s Summit. 265 people are discussing very important (and interesting) topics for Qt 5 and the open governance. You can follow what’s happening here using the hash code #qtcs on several social networks. And of course, you can check the wiki page of the event.

Personally, I am attending sessions related with QML, Qt-Components, DevNet and open governance.

And yesterday was Thursday, also known as the “Yellow Day”:

The event is about to begin with the keynote “The Future of MeeGo Starts Now” presented by the president of Linux Foundation, Jim Zemlin.

This time, I’m going to present a talk in the event too! The talk is today and the topic is “Writing applications for multiple MeeGo devices”.

There are other talks by openBossa/INdT guys, check the schedule!

After the Qt Dev Days San Francisco, I went quickly to Natal to present a talk about Qt and KDE on mobile devices. It’s time to say thank you for the ENSL organizers – As always, I am late with my posts…

So, last week we went to Dublin, for the MeeGo Conference 2010. As more people already posted, it was a really nice event. The good surprise was the limit of the number of Intel and Nokia people, leaving space for the growing community meet – more than a thousand people attended, very well accommodated in the place chosen (the conference rooms in the Aviva Stadium) with a good work of the organization which managed to keep things working nicely.

Although the short time of the presentations, it was good to have a whole ideaof how the project is being conduced, and it looks promising. Unfortunately I left Dublin on Wednesday morning, so I lost the last day which was reserved for the ‘unconference‘ sections and the football match, but I managed to go to the Guinness Storehouse in Tuesday night, a really good choice for the conference after hours.

With the Lenovo ideapad received from the MeeGo Conference guys (thanks! :-)) in my backpack, I traveled to Berlin for the KDE Mobile Sprint, kindly hosted by KDAB in its office.

I must say, we had fun with the new devices. :-)
During the sprint, interesting discussions about MeeGo, new opportunities, QML and Qt-components. Some of the guys dedicated their time to KDE packaging for MeeGo while in parallel other ones worked in QML based widgets for plasma, tested how some applications work on the ideapad’s touchscreen, and tested plasma-mobile and plasma-tablet shells on it. The results of this sprint are being listed in this wiki page.

The first steps :-)

Check the videos in Marco’s and Artur’s posts about the sprint. Also, Till Adam showing Kontact Mobile on MeeGo.

Of course there is more work to do, but considering how things worked without special attention to this device (and for MeeGo), we can expect good news in the future.

And here a screenshot of the gallery to test the Plasma QML widgets, with a FlashingLabel, some BusyWidgets and a PushButton. It’s just the beginning.

I know, the gallery is, let's say, weird... :-P

Someone said a few weeks ago that a good post must have a picture. Here is a picture of the Municipal Park and the  ”Hippie Fair“, in Belo Horizonte:

BUT… there are people who prefer “Livin’ on the Edge“. If you are one of those and already want/need to develop with Qt 4.7 (not released yet!) for Maemo 5, using MADDE to build your applications / packages, here is an update to the procedure first published by the troll Harald Fernengel (AKA harryF). Although the title says “on MacOS X”, the steps also work on Linux.

Step-by-step:

• Install MADDE. Download it here.
• If you are not using a Debian based distro, you need to install the “Tools for Debian Packages” package of your distribution (e.g. “deb” on openSUSE, sys-apps/debianutils on Gentoo).
• Download the script fetch-qt4.7.0-latest.sh. This script downloads the libqt4-experimental packages from repository.maemo.org and installs then in your MADDE – Before you run the script, remember to adjust the MADDE_PATH variable according to the path you installed MADDE.
• Download qt4-tools-latest.tar.gz. It contains the Qt tools compiled for the correspondent version, configured for cross compiling. Extract to /opt/qt4-maemo5.
• Check if mad is in your PATH.

To build an application using your fresh environment, run /opt/qt4-maemo5/bin/qmake && make .

If you succeeded in the setup process, this should result in a armel binary ready to run on N900. To generate a deb package, you can use the tools offered by MADDE to build a skeleton of debian package and so on.

To run your application on N900, install libqt4-experimental-* packages. If QtQuick (QML) is part of your plans, qmlviewer  is in the package qt4-experimental-declarative-qmlviewer .

UPDATE (2010-06-15): For newer (or older) versions, check http://anselmolsm.org/public/qt/madde-qt47/

UPDATE (2010-09-09): Links updated to download the latest version.

In the first season, the focus was S60 devices. After the holidays, the new season is about Maemo. =)

Qt Mobile Demos are in Maemo 5 extras-devel, so now it’s easier to check them in a N900 near you. First, you need to enable the extras-devel repository/catalogue and the demos should appear if you search for “qtmobile”.

The packages are:

hyperui -> qtmobiledemo-hyperui

mybudget -> qtmobiledemo-mybudget

shoplist -> qtmobiledemo-shoplist

weather -> qtmobiledemo-weather

Future? Well, soon QAbstractKineticScroller will replace our kinetic list implementation. (Read the comments).

And yes, we have a list of known issues to solve in our free time…

The code still in the same place, http://qt.gitorious.org/qt-labs/mobile-demos

That’s all for today.

PS: Thanks to Etrunko, who helped a lot with packaging stuff =)

To celebrate the new version of Qt, the first with the S60 port, we thought it would be nice if people could also check those demos on desktop platforms. You know, Qt is everywhere =)

As the release was yesterday, probably there are people without Qt 4.6 installed in their desktops yet… so we prepared binaries with Qt 4.6.0 statically linked =)

Linux version

Windows version

Mac version (Unfortunately I don’t have a Mac available here right now. Contributions are welcome =)

It’s worth a mention. The source code for all platforms is basically the same, the only difference are due to different screen sizes, different connections methods.  This code is still available in the same place: http://gitorious.org/qt-labs/mobile-demos

And again, owners of  either S60 devices or N900 find packages at: http://qtlabs.openbossa.org/mobile-demos .

—

TODO: Fix the bug in the weather demo when there’s no connection…

PS1: As an extra activity, support for keypads is work in progress (I have a N85 =P )

PS2:  Now that Qt 4.6.0 is out, it’s a good moment to make it work again …

PS3: Hello planet KDE! o/