whsilikon.blogg.se - Qt quick desktop application example

#QT QUICK DESKTOP APPLICATION EXAMPLE HOW TO#
#QT QUICK DESKTOP APPLICATION EXAMPLE INSTALL#
#QT QUICK DESKTOP APPLICATION EXAMPLE SOFTWARE#
#QT QUICK DESKTOP APPLICATION EXAMPLE CODE#

When you create an object of this class and call its exec() function, main never returns. To achieve this, run your program in a loop till this happens, so you use the event-loop-based class QApplication. We want the GUI to run until the user closes the window. However, in GUI programs, we can’t do that, or the application will not be usable. The program terminates when main returns. Create a directory (first) and create a simple “Hello World” program with the following code: #include Just chmod the installer file to make it executable and run it, and then follow the prompts.

#QT QUICK DESKTOP APPLICATION EXAMPLE INSTALL#

If you want to try out the latest Qt release, you can download the offline installer from their official website and install it. On Ubuntu 10.04 LTS, I installed Qt via the Synaptic package manager - install the qtcreator package dependency resolution will install Qt Assistant, Qt Designer, Qt Linguist and Qt Creator. As Qt development progressed, it was getting difficult to support both C++ and Java, so the decision was made to support only C++. Earlier, Qt also supported Java its Java-based version was called Jambie. Below that are Qt classes for GUI, WebKit, databases, etc., and then an OS-specific support layer. In Figure 1, you can see a minimal architecture diagram. As far as platform support is concerned, it supports Linux, Mac OS, Windows, Meego, Embedded Linux and Symbian. Qt can help with graphical application development, network applications, database and multimedia applications, handling XML and 3D, painting, drawing and Web access. Qt has been extensively used by application developers to develop cross-platform applications. Qt is a cross-platform application framework developed by Trolltech and presently owned by Nokia. We have some frameworks that support C++ for application development. Application development using C is time-consuming, while C++ is a better option.

So again, the need is to develop applications compilable to native code. No doubt Java is still a leading language, but these days we have some really big data applications (for example, in biotech) with very high performance requirements. Another problem is the large memory footprint. The performance of Java applications is not as good as of C/C++ applications compiled to platform-native code. In Java’s case, the price was application performance.

#QT QUICK DESKTOP APPLICATION EXAMPLE CODE#

Code developed once can be deployed to every platform that has a JVM for it.īut everything comes with a price. Java applications run on the Java Virtual Machine (JVM). This does make life easier for developers - but then everything changed with the revolutionary concept of virtual machines from Sun Microsystems, which gave the world the platform-independent Java programming language. One method was to develop libraries for each platform, keeping application code the same and recompiling for each target platform.

#QT QUICK DESKTOP APPLICATION EXAMPLE HOW TO#

A big question was how to write platform-independent applications. An application compiled for Linux cannot be directly executed on another OS without some sort of emulation, due to differences in system calls and libraries between OSs.

Libraries are called from application code, but the framework calls application code - or, you can say, provides services to the code.ĭesktop applications are very platform-specific.

A library may provide functions used for signals/events, but the framework function is how they interact with the system and other components.

For example, a library may provide classes for TCP and UDP sockets, while a framework will provide a class for an abstract socket.

Libraries offer reusability of functionality, whereas frameworks offer reusability of behaviour.

Though libraries and frameworks seem to functionally be the same, there are some major differences between them, which should be understood:

#QT QUICK DESKTOP APPLICATION EXAMPLE SOFTWARE#

Static and shared libraries were created for use in application development, but developers didn’t stop at that they came up with software frameworks. There was a time when all desktop applications were developed from scratch. This article introduces application development using the Qt GUI framework.