Qt 学习之路 2(4):信号槽

Qt 5 was officially released on 19 December A new name and a new look for Catalyst". Warns when a lambda inside a connect captures local variables by reference. This gives several benefits:. Each object can be given a special unique property called an id.

Class Inheritance in QML


With Qt Quick, rapid application development for mobile devices became possible, while logic can still be written with native code as well to achieve the best possible performance. The latest version is Qt 5. It comes with several new features including initial Vulkan support for Windows, Linux and Android. The current LTS version is Qt 5. It was released on 31 May and will be supported for 3 years until 31 May In , the Qt Company estimates a community of approximately 1 million developers worldwide [19] in over 70 industries.

Several GUIs and desktop environments utilize Qt as widget toolkit:. There are cases where applications have ported their user interface code from another toolkit to Qt to make use of a cross-platform native GUI, such as the Wireshark network packet analyzer, LXQt desktop, VLC media player and the Rosegarden audio editor.

After Nokia opened the Qt source code to the community on Gitorious various ports appeared. There are also some ports of Qt that may be available, but are not supported anymore.

These platforms are listed in List of platforms supported by Qt. Qt can be used in several other programming languages via language bindings , see. Starting with Qt 4. There are four editions of Qt available: Community , Indie Mobile , Professional and Enterprise.

Enterprise Controls [] are commercially sold by The Qt Company. Qt is available under the following free software licenses: In addition, Qt has always been available under a commercial license, like the Qt Commercial License , [5] that allows developing proprietary applications with no restrictions on licensing. Qt comes with its own set of tools to ease cross-platform development, which can otherwise be cumbersome due to different set of development tools.

In addition to Qt Creator, Qt provides qmake , a cross-platform build script generation tool that automates the generation of Makefiles for development projects across different platforms.

There are other tools available in Qt, including the Qt Designer interface builder and the Qt Assistant help browser which are both embedded in Qt Creator , the Qt Linguist translation tool, uic user interface compiler , and moc Meta-Object Compiler.

The toolkit was called Qt because the letter Q looked appealing in Haavard's Emacs typeface, and "t" was inspired by Xt , the X toolkit. On 20 May Troll Tech publicly released Qt 0. Trolltech used this license until version 1.

Controversy erupted around when it became clear that the K Desktop Environment was going to become one of the leading desktop environments for Linux. As it was based on Qt, many people in the free software movement worried that an essential piece of one of their major operating systems would be proprietary.

With the release of version 2. Compromises were sought between KDE and Trolltech whereby Qt would not be able to fall under a more restrictive license than the QPL, even if Trolltech was bought out or went bankrupt. At the end of , Trolltech released Qt 3.

This was resolved when Trolltech released Qt 4. The GPL v3 with special exception [] was later added as an added licensing option. Nokia focused on turning Qt into the main development platform for its devices, including a port to the Symbian S60 platform. On 14 January , Qt version 4.

In February , Nokia announced its decision to drop Symbian technologies and base their future smartphones on the Windows Phone platform instead. In September , Digia transferred the Qt business and copyrights to their wholly owned subsidiary, The Qt Company, which owns 25 brands [] related to Qt. In May , Digia and Qt demerged completely into two independent companies. Qt 5 was officially released on 19 December This new version marked a major change in the platform, with hardware-accelerated graphics, QML and JavaScript playing a major role.

Framework development of Qt 5 moved to open governance at qt-project. Aside from The Qt Company, many organizations and individuals using Qt as their development platform participate in the open development of Qt itself via the Qt Project. Another participator is Intel , contributing for example Wayland support. Qt Wiki provides a comprehensive list of English books about Qt.

From Wikipedia, the free encyclopedia. Redirected from Qt toolkit. Software that uses Qt. Proprietary software that uses Qt. List of platforms supported by Qt. List of language bindings for Qt 4 and List of language bindings for Qt 5. Blanchette, Jasmin; Summerfield, Mark 14 February Summerfield, Mark 23 August Archived from the original on 19 December Summerfield, Mark 28 October Molkentin, Daniel 19 July The Art of Building Qt Applications" 1st ed.

Thelin, Johan 3 August Dalheimer, Matthias January Ezust, Alan; Ezust, Paul 10 September Retrieved 5 August Retrieved 19 February Retrieved 7 September Retrieved 8 May Retrieved 1 June Retrieved 8 June Retrieved 30 June Archived from the original on 23 July Making the Apps that Make the Movies.

Archived from the original on 14 July Archived from the original on 30 July Archived from the original on 6 May A property binding specifies the value of a property in a declarative way.

The property value is automatically updated if the other properties or data values change, following the reactive programming paradigm. Property bindings are created implicitly in QML whenever a property is assigned a JavaScript expression.

The following QML uses two property bindings to connect the size of the rectangle to that of otherItem. QML extends a standards-compliant JavaScript engine, so any valid JavaScript expression can be used as a property binding. Bindings can access object properties, make function calls, and even use built-in JavaScript objects like Date and Math.

States are a mechanism to combine changes to properties in a semantic unit. A button for example has a pressed and a non-pressed state, an address book application could have a read-only and an edit state for contacts.

Every element has an "implicit" base state. Every other state is described by listing the properties and values of those elements which differ from the base state.

In the default state, myRect is positioned at 0,0. In the "moved" state, it is positioned at 50, Clicking within the mouse area changes the state from the default state to the "moved" state, thus moving the rectangle. For example, adding this code to the above Item element animates the transition to the "moved" state:. Animations in QML are done by animating properties of objects. Properties of type real, int, color, rect, point, size, and vector3d can all be animated. QML supports three main forms of animation: The simplest form of animation is a PropertyAnimation, which can animate all of the property types listed above.

A property animation can be specified as a value source using the Animation on property syntax. This is especially useful for repeating animations. Signal handlers are JavaScript callbacks which allow imperative actions to be taken in response to an event. For instance, the MouseArea element has signal handlers to handle mouse press, release and click:. The qml executable can be used to run a QML file as a script. If the QML file begins with a shebang it can be made directly executable.

From Wikipedia, the free encyclopedia. For other uses, see QML disambiguation. This article relies too much on references to primary sources.

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