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Qt (pronunciation official [kju: t], sound the same cute) is a cross-platform C ++ development libraries, is mainly used to develop graphical user interface (Graphical User Interface, GUI) program, of course, can develop command without the interface line ( Command User Interface, CUI) program.
Qt is pure C ++ development, it is necessary to learn C ++ , C ++ do not understand for the reader, I recommend that you read the " C language tutorial " and then read, " C ++ tutorial ." C ++ is a C language developed based on the C language school finish school half of the C ++.
There Qt Python bindings, Ruby, Perl and other scripting language, which means you can use scripting language development program based on Qt. The open source community is such a good thing will be derived extension, use everywhere, more and more stronger.
Qt supported operating systems are available, such general-purpose operating system, Windows, Linux , Unix, smart phone system Android , iOS, WinPhone, embedded systems QNX, VxWorks, and so on.
Qt icon (Logo)
Qt What can be done?
Although often treated as a Qt GUI library for developing GUI applications , but not all of Qt; Qt can draw in addition to beautiful interface (including controls, layout, interactive), also contains many other features, such as multi-threading , access to the database, image processing, audio and video processing, network communication, file operations, etc. , which have been built in Qt.
Qt is the application development of one-stop solution, with Qt, you can sit back and relax! Qt itself contains modules also increasingly rich, there have been new modules and third-party modules join.
Most applications can use Qt to achieve, particularly tight, such as in conjunction with computer-driven development in addition to the bottom, it directly using a programming interface provided by the hardware, operating system and can not use the built-in function library.
In 1997, Qt is used to develop Linux desktop environment KDE, with great success, becoming the Qt C ++ GUI development program under the de facto standard Linux environment.
The following program uses Qt development: WPS, YY voice, the Battle.net client Skype, Douban radio, shrimp music, Taobao assistant, kN, Blizzard, VirtualBox, Opera, microphone cushions Music, Google Maps, Adobe Photoshop Album and so on.
Embedded Linux is the main force, widely used in consumer electronics, industrial control, military electronics, telecommunications / networking / communications, aerospace, automotive electronics, medical equipment, instrumentation and other related industries.
Although Qt also supports mobile operating system, but due to Android itself has Java and Kotlin, iOS itself has Objective-C and Swift, so Qt is almost negligible in the mobile terminal market share.
Collectively, Qt is mainly used for the development of desktop applications and embedded development.
Qt and smartphones
Qt currently supports mainstream Android, iOS, WinPhone and other intelligent operating system. MeeGo is Qt-based operating system developed by Nokia due to being abandoned, leaving only a generation out of print Nokia N9 mobile phone.
After Nokia's mobile phone unit sale to Microsoft, most of the Nokia mobile phone system developers have been dismissed.
- The original part of Nokia's people set up new Jolla (Zhuo blue) company, announced the derivative version of MeeGo smart phone system Sailfish (swordfish), in the phone and started selling tablet also released.
- Another call people seeking refuge Tizen (Taize), Tizen Intel and Samsung are pushing smart phone system, which integrates Limo and MeeGo, MeeGo system was abandoned because of Nokia, Intel in fact been betrayed, we can only joint Samsung re-create the smart phone system Tizen.
Currently based Tizen's first mobile phone Samsung Z1 in India market. In Tizen camp, domestic ZTE, Baidu involved. Qt open source projects where there Qt for Tizen version, are interested can go to Soso.
Qt company has developed specifically for mobile commercial version, 20 euros or 25 dollars a month. Business can not ignore this, use the open source version also can develop such as Android, iOS, WinPhone application.
This tutorial is concerned that traditional desktop operating system development, mobile development can refer to the official Qt documentation.
Qt's bitter history
When it comes to the history of the development of Qt, then it twists and turns, twists and bondage.
Qt was first in 1991 by the Norwegian Eirik Chambe-Eng and Haavard Nord development, they followed on March 4, 1994 formally established Trolltech (Trolltech). Qt was originally a commercial license for cross-platform development library, in 2000, Trolltech released the open source community to follow the GPL (GNU General Public License) license open source version.
In 2008, Nokia acquired Trolltech, and increases the LGPL (GNU Lesser General Public License) licensing model . Nokia and Intel use Qt to develop a new smart phone system MeeGo, but unfortunately suffered a Trojan horse Microsoft, Nokia was forced to abandon MeeGo, Qt commercial licensing business and also sold in March 2011 to the Finnish IT service company Digia.
Of course, the good news is Digia announced in September 2014 set up Qt Company, a wholly owned subsidiary of independent operators Qt commercial licensing business. Currently Qt company to promote mobile platform development and commercial applications, in general Qt through twists and turns, now considered the right track.
After 20 years of development, Qt has become one of the best cross-platform development framework, widely used in all walks of life in the project development. Many large software is developed with Qt, such as Autodesk Maya, Google Earth, Skype, WPS Office and so on.
Never ignore the threat of the Microsoft empire, as a generation of dominant software industry, no one should naively tried to make friends with it, because there can be no dominant friend. Microsoft's Trojan horse and Finns are all Nokia pain, hope readers will remember the simplicity of this.
Qt and KDE
The previously mentioned commercial Qt was originally licensed software, open source is how it? This involves the entanglement of the Qt and KDE.
KDE is a Linux operating system desktop environment with the GNOME desktop is similar, as they compete in the open source desktop cases are more common, interested readers, please hit " Linux desktop environment " for more.
KDE is released under the GPL license open source software, and is the first Qt commercial license, there is a risk of infringement of commercial, open source GNOME is based on GTK libraries, no commercial risk, a fact that is superior to GNOME KDE features.
Since the commercial license of Qt, KDE community was chaotic tangle, while GNOME is in full swing developed. KDE after all, regarded as pro-son, another wave of people being bullied, Trolltech course could not stand, and finally Trolltech company in order to win the support of developers, in order to increase the open-source license Qt under the GPL for open source communities , use Qt under the GPL will not be billed, which addresses the immediate need for the KDE.
After the KDE and GNOME desktops have grown up, we are doing better and better.
GPL and LGPL
In addition to a commercial license, open source Qt currently authorized, there are two, one is the GPL license, and the other is the LGPL license (after the acquisition of Nokia's new).
These two open-source license, in simple terms, the GPL version of the software must still GPL open-source software, whether it is using Qt program code or modify the Qt library code must be released under the GPL, which is GPL infection sex.
GPL is what should be open source, which is detrimental to business software applications, so Nokia increased the LGPL license (first L version can be called Lesser loose or Library development library version). Use the LGPL license can take advantage of the official Qt dynamic link library without having to open the commercial code. They do not modify and customize the Qt library, use only the official release of Qt dynamic link library can not open source, this is a commercial-friendly licensing model.
In fact, as long as not to do business, we need to focus on what is not authorized to release GPL-licensed program code on it.
Open source license in the world there are a lot of interested readers, please hit " What protocol is open source? What? how to choose? "Learn more.
Finally, please look for Qt official website (and sometimes can not even access is slow access, please bring your own ladder reader), you can access a document or browsing information: https://www.qt.io/