Remove echo plugin
Remove echo plugin code and documentation. Fixes: QTBUG-119981 Change-Id: I4083ac6cdb768facaed041241af2c5ee6e28df50 Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io> (cherry picked from commit 01bf423d67d5e6f8de5ec51a6b85178492681ca9) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Axel Spoerl
Qt Cherry-pick Bot
parent
d8b113f46f
commit
83df3a8138
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@ -1,180 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
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/*!
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\example tools/echoplugin
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\title Echo Plugin Example
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\examplecategory {Data Processing & I/O}
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\ingroup examples-widgets-tools
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\ingroup examples-layout
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\brief This example shows how to create a Qt plugin.
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\image echopluginexample.png
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There are two kinds of plugins in Qt: plugins that extend Qt
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itself and plugins that extend applications written in Qt. In this
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example, we show the procedure of implementing plugins that extend
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applications. When you create a plugin you declare an interface,
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which is a class with only pure virtual functions. This interface
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is inherited by the class that implements the plugin. The class is
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stored in a shared library and can therefore be loaded by
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applications at run-time. When loaded, the plugin is dynamically
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cast to the interface using Qt's \l{Meta-Object
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System}{meta-object system}. The plugin \l{How to Create Qt
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Plugins}{overview document} gives a high-level introduction to
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plugins.
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We have implemented a plugin, the \c EchoPlugin, which implements
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the \c EchoInterface. The interface consists of \c echo(), which
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takes a QString as argument. The \c EchoPlugin returns the string
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unaltered (i.e., it works as the familiar echo command found in
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both Unix and Windows).
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We test the plugin in \c EchoWindow: when you push the QPushButton
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(as seen in the image above), the application sends the text in
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the QLineEdit to the plugin, which echoes it back to the
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application. The answer from the plugin is displayed in the
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QLabel.
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\section1 EchoWindow Class Definition
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The \c EchoWindow class lets us test the \c EchoPlugin through a
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GUI.
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\snippet tools/echoplugin/echowindow/echowindow.h 0
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We load the plugin in \c loadPlugin() and cast it to \c
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EchoInterface. When the user clicks the \c button we take the
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text in \c lineEdit and call the interface's \c echo() with it.
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\section1 EchoWindow Class Implementation
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We start with a look at the constructor:
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\snippet tools/echoplugin/echowindow/echowindow.cpp 0
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We create the widgets and set a title for the window. We then load
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the plugin. \c loadPlugin() returns false if the plugin could not
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be loaded, in which case we disable the widgets. If you wish a
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more detailed error message, you can use
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\l{QPluginLoader::}{errorString()}; we will look more closely at
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QPluginLoader later.
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Here is the implementation of \c sendEcho():
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\snippet tools/echoplugin/echowindow/echowindow.cpp 1
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This slot is called when the user pushes \c button or presses
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enter in \c lineEdit. We call \c echo() of the echo interface. In
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our example this is the \c EchoPlugin, but it could be any plugin
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that inherit the \c EchoInterface. We take the QString returned
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from \c echo() and display it in the \c label.
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Here is the implementation of \c createGUI():
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\snippet tools/echoplugin/echowindow/echowindow.cpp 2
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We create the widgets and lay them out in a grid layout. We
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connect the label and line edit to our \c sendEcho() slot.
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Here is the \c loadPlugin() function:
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\snippet tools/echoplugin/echowindow/echowindow.cpp 3
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Access to plugins at run-time is provided by QPluginLoader. You
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supply it with the filename of the shared library the plugin is
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stored in and call \l{QPluginLoader::}{instance()}, which loads
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and returns the root component of the plugin (i.e., it resolves
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the type of the plugin and creates a QObject instance of it). If
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the plugin was not successfully loaded, it will be null, so we
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return false. If it was loaded correctly, we can cast the plugin
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to our \c EchoInterface and return true. In the case that the
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plugin loaded does not implement the \c EchoInterface, \c
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instance() will return null, but this cannot happen in our
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example. Notice that the location of the plugin is not the same
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for all platforms.
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\section1 EchoInterface Class Definition
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The \c EchoInterface defines the functions that the plugin will
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provide. An interface is a class that only consists of pure
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virtual functions. If non virtual functions were present in the
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class you would get misleading compile errors in the moc files.
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\snippet tools/echoplugin/echowindow/echointerface.h 0
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We declare \c echo(). In our \c EchoPlugin we use this method to
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return, or echo, \a message.
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We use the Q_DECLARE_INTERFACE macro to let \l{Meta-Object
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System}{Qt's meta object system} aware of the interface. We do
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this so that it will be possible to identify plugins that
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implements the interface at run-time. The second argument is a
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string that must identify the interface in a unique way.
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\section1 EchoPlugin Class Definition
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We inherit both QObject and \c EchoInterface to make this class a
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plugin. The Q_INTERFACES macro tells Qt which interfaces the class
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implements. In our case we only implement the \c EchoInterface.
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If a class implements more than one interface, they are given as
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a space separated list. The Q_PLUGIN_METADATA macro is included next
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to the Q_OBJECT macro. It contains the plugins IID and a filename
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pointing to a json file containing the metadata for the plugin.
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The json file is compiled into the plugin and does not need to be installed.
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\snippet tools/echoplugin/plugin/echoplugin.h 0
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\section1 EchoPlugin Class Implementation
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Here is the implementation of \c echo():
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\snippet tools/echoplugin/plugin/echoplugin.cpp 0
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We simply return the functions parameter.
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\section1 The \c main() function
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\snippet tools/echoplugin/echowindow/main.cpp 0
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We create an \c EchoWindow and display it as a top-level window.
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\section1 The Profiles
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When creating plugins the profiles need to be adjusted.
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We show here what changes need to be done.
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The profile in the echoplugin directory uses the \c subdirs
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template and simply includes includes to directories in which
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the echo window and echo plugin lives:
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\snippet tools/echoplugin/echoplugin.pro 0
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The profile for the echo window does not need any plugin specific
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settings. We move on to the plugin profile:
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\snippet tools/echoplugin/plugin/plugin.pro 0
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We need to set the TEMPLATE as we now want to make a library
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instead of an executable. We also need to tell qmake that we are
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creating a plugin. The \c EchoInterface that the plugin implements
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lives in the \c echowindow directory, so we need to add that
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directory to the include path. We set the TARGET of the project,
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which is the name of the library file in which the plugin will be
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stored; qmake appends the appropriate file extension depending on
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the platform. By convention the target should have the same name
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as the plugin (set with Q_EXPORT_PLUGIN2)
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\section1 Further Reading and Examples
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The \l {qtplugin-defining-plugins}{Defining Plugins} page presents an overview of the macros needed to
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create plugins.
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We give an example of a plugin that extends Qt in the \l{Style
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Plugin Example}{style plugin} example.
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*/
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@ -130,8 +130,4 @@
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In addition to the plugin \l{How to Create Qt Plugins}{overview
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document}, we have other examples and articles that concern
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plugins.
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In the \l{Echo Plugin Example}{echo plugin example} we show how to
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implement plugins that extends Qt applications rather than Qt
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itself, which is the case with the style plugin of this example.
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*/
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@ -7,7 +7,3 @@ qt_internal_add_example(regularexpression)
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qt_internal_add_example(styleplugin)
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qt_internal_add_example(treemodelcompleter)
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qt_internal_add_example(undoframework)
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if(QT_FEATURE_library)
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qt_internal_add_example(echoplugin)
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endif()
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@ -1,18 +0,0 @@
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# Copyright (C) 2022 The Qt Company Ltd.
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# SPDX-License-Identifier: BSD-3-Clause
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cmake_minimum_required(VERSION 3.16)
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project(echoplugin LANGUAGES CXX)
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if(NOT DEFINED INSTALL_EXAMPLESDIR)
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set(INSTALL_EXAMPLESDIR "examples")
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endif()
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set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/widgets/tools/echoplugin")
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find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
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qt_standard_project_setup()
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add_subdirectory(plugin)
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add_subdirectory(echowindow)
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@ -1,5 +0,0 @@
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#! [0]
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TEMPLATE = subdirs
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SUBDIRS = echowindow \
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plugin
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#! [0]
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@ -1,35 +0,0 @@
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# Copyright (C) 2022 The Qt Company Ltd.
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# SPDX-License-Identifier: BSD-3-Clause
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qt_add_executable(echopluginwindow
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echointerface.h
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echowindow.cpp echowindow.h
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main.cpp
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)
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set_target_properties(echopluginwindow PROPERTIES
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WIN32_EXECUTABLE TRUE
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MACOSX_BUNDLE TRUE
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)
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target_link_libraries(echopluginwindow PRIVATE
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Qt6::Core
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Qt6::Gui
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Qt6::Widgets
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)
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if(QT6_IS_SHARED_LIBS_BUILD)
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# Build the shared plugin too when building this example target.
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add_dependencies(echopluginwindow echoplugin)
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else()
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# Link the echoplugin if Qt is built statically.
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target_link_libraries(echopluginwindow PRIVATE
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echoplugin
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)
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endif()
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install(TARGETS echopluginwindow
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RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
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BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
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LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
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)
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@ -1,27 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#ifndef ECHOINTERFACE_H
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#define ECHOINTERFACE_H
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#include <QObject>
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#include <QString>
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//! [0]
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class EchoInterface
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{
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public:
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virtual ~EchoInterface() = default;
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virtual QString echo(const QString &message) = 0;
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};
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QT_BEGIN_NAMESPACE
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#define EchoInterface_iid "org.qt-project.Qt.Examples.EchoInterface"
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Q_DECLARE_INTERFACE(EchoInterface, EchoInterface_iid)
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QT_END_NAMESPACE
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//! [0]
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#endif
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@ -1,90 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#include "echowindow.h"
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#include <QCoreApplication>
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#include <QDir>
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#include <QLabel>
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#include <QLayout>
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#include <QLineEdit>
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#include <QMessageBox>
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#include <QPluginLoader>
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#include <QPushButton>
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//! [0]
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EchoWindow::EchoWindow()
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{
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createGUI();
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setLayout(layout);
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setWindowTitle("Echo Plugin Example");
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if (!loadPlugin()) {
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QMessageBox::information(this, "Error", "Could not load the plugin");
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lineEdit->setEnabled(false);
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button->setEnabled(false);
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}
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}
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//! [0]
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//! [1]
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void EchoWindow::sendEcho()
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{
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QString text = echoInterface->echo(lineEdit->text());
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label->setText(text);
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}
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//! [1]
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//! [2]
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void EchoWindow::createGUI()
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{
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lineEdit = new QLineEdit;
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label = new QLabel;
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label->setFrameStyle(QFrame::Box | QFrame::Plain);
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button = new QPushButton(tr("Send Message"));
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connect(lineEdit, &QLineEdit::editingFinished,
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this, &EchoWindow::sendEcho);
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connect(button, &QPushButton::clicked,
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this, &EchoWindow::sendEcho);
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layout = new QGridLayout;
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layout->addWidget(new QLabel(tr("Message:")), 0, 0);
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layout->addWidget(lineEdit, 0, 1);
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layout->addWidget(new QLabel(tr("Answer:")), 1, 0);
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layout->addWidget(label, 1, 1);
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layout->addWidget(button, 2, 1, Qt::AlignRight);
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layout->setSizeConstraint(QLayout::SetFixedSize);
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}
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//! [2]
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//! [3]
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bool EchoWindow::loadPlugin()
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{
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QDir pluginsDir(QCoreApplication::applicationDirPath());
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#if defined(Q_OS_WIN)
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if (pluginsDir.dirName().toLower() == "debug" || pluginsDir.dirName().toLower() == "release")
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pluginsDir.cdUp();
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#elif defined(Q_OS_MAC)
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if (pluginsDir.dirName() == "MacOS") {
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pluginsDir.cdUp();
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pluginsDir.cdUp();
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pluginsDir.cdUp();
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}
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#endif
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pluginsDir.cd("plugins");
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const QStringList entries = pluginsDir.entryList(QDir::Files);
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for (const QString &fileName : entries) {
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QPluginLoader pluginLoader(pluginsDir.absoluteFilePath(fileName));
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QObject *plugin = pluginLoader.instance();
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if (plugin) {
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echoInterface = qobject_cast<EchoInterface *>(plugin);
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if (echoInterface)
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return true;
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pluginLoader.unload();
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}
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}
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return false;
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}
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//! [3]
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@ -1,42 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#ifndef ECHODIALOG_H
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#define ECHODIALOG_H
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#include <QWidget>
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#include "echointerface.h"
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QT_BEGIN_NAMESPACE
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class QString;
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class QLineEdit;
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class QLabel;
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class QPushButton;
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class QGridLayout;
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QT_END_NAMESPACE
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//! [0]
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class EchoWindow : public QWidget
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{
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Q_OBJECT
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public:
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EchoWindow();
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private slots:
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void sendEcho();
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private:
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void createGUI();
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bool loadPlugin();
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EchoInterface *echoInterface;
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QLineEdit *lineEdit;
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QLabel *label;
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QPushButton *button;
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QGridLayout *layout;
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};
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//! [0]
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#endif
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@ -1,21 +0,0 @@
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QT += widgets
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HEADERS = echowindow.h \
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echointerface.h
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SOURCES = echowindow.cpp \
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main.cpp
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TARGET = echoplugin
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QMAKE_PROJECT_NAME = echopluginwindow
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win32 {
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CONFIG(debug, release|debug):DESTDIR = ../debug/
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CONFIG(release, release|debug):DESTDIR = ../release/
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} else {
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DESTDIR = ../
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}
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# install
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target.path = $$[QT_INSTALL_EXAMPLES]/widgets/tools/echoplugin
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INSTALLS += target
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CONFIG += install_ok # Do not cargo-cult this!
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@ -1,19 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#include <QApplication>
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#include "echowindow.h"
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#include "echointerface.h"
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//! [0]
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int main(int argv, char *args[])
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{
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QApplication app(argv, args);
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EchoWindow window;
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window.show();
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return app.exec();
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}
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//! [0]
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@ -1,26 +0,0 @@
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# Copyright (C) 2022 The Qt Company Ltd.
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# SPDX-License-Identifier: BSD-3-Clause
|
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|
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qt_add_plugin(echoplugin
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CLASS_NAME EchoPlugin
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echoplugin.cpp echoplugin.h
|
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)
|
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|
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set_target_properties(echoplugin PROPERTIES
|
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LIBRARY_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/echowindow"
|
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)
|
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|
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target_include_directories(echoplugin PRIVATE
|
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../echowindow
|
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)
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|
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target_link_libraries(echoplugin PRIVATE
|
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Qt6::Core
|
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Qt6::Gui
|
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Qt6::Widgets
|
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)
|
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|
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install(TARGETS echoplugin
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RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
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LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
|
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)
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@ -1,11 +0,0 @@
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// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
|
||||
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||||
#include "echoplugin.h"
|
||||
|
||||
//! [0]
|
||||
QString EchoPlugin::echo(const QString &message)
|
||||
{
|
||||
return message;
|
||||
}
|
||||
//! [0]
|
||||
@ -1,23 +0,0 @@
|
||||
// Copyright (C) 2016 The Qt Company Ltd.
|
||||
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
|
||||
|
||||
#ifndef ECHOPLUGIN_H
|
||||
#define ECHOPLUGIN_H
|
||||
|
||||
#include <QObject>
|
||||
#include <QtPlugin>
|
||||
#include "echointerface.h"
|
||||
|
||||
//! [0]
|
||||
class EchoPlugin : public QObject, EchoInterface
|
||||
{
|
||||
Q_OBJECT
|
||||
Q_PLUGIN_METADATA(IID "org.qt-project.Qt.Examples.EchoInterface" FILE "echoplugin.json")
|
||||
Q_INTERFACES(EchoInterface)
|
||||
|
||||
public:
|
||||
QString echo(const QString &message) override;
|
||||
};
|
||||
//! [0]
|
||||
|
||||
#endif
|
||||
@ -1 +0,0 @@
|
||||
{}
|
||||
@ -1,18 +0,0 @@
|
||||
#! [0]
|
||||
TEMPLATE = lib
|
||||
CONFIG += plugin
|
||||
QT += widgets
|
||||
INCLUDEPATH += ../echowindow
|
||||
HEADERS = echoplugin.h
|
||||
SOURCES = echoplugin.cpp
|
||||
TARGET = $$qtLibraryTarget(echoplugin)
|
||||
DESTDIR = ../plugins
|
||||
#! [0]
|
||||
|
||||
EXAMPLE_FILES = echoplugin.json
|
||||
|
||||
# install
|
||||
target.path = $$[QT_INSTALL_EXAMPLES]/widgets/tools/echoplugin/plugins
|
||||
INSTALLS += target
|
||||
|
||||
CONFIG += install_ok # Do not cargo-cult this!
|
||||
@ -2,13 +2,8 @@ TEMPLATE = subdirs
|
||||
SUBDIRS = \
|
||||
completer \
|
||||
customcompleter \
|
||||
echoplugin \
|
||||
regularexpression \
|
||||
styleplugin \
|
||||
treemodelcompleter \
|
||||
undoframework
|
||||
|
||||
!qtConfig(library) {
|
||||
SUBDIRS -= \
|
||||
echoplugin
|
||||
}
|
||||
|
||||
@ -71,7 +71,7 @@ using namespace Qt::StringLiterals;
|
||||
link to plugins statically. You can use QLibrary if you need to
|
||||
load dynamic libraries in a statically linked application.
|
||||
|
||||
\sa QLibrary, {Echo Plugin Example}
|
||||
\sa QLibrary
|
||||
*/
|
||||
|
||||
static constexpr QLibrary::LoadHints defaultLoadHints = QLibrary::PreventUnloadHint;
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user