Merge pull request #167 from samsonwang/master

Windows raise widget example

.github/workflows/main.yml

@@ -59,7 +59,7 @@ jobs:
           cmake . ${{ matrix.additional_arguments }}
           cmake --build .
 
-      - name: Build calculator example CMake
+      - name: Build calculator example with CMake
         working-directory: examples/calculator/
         run: |
           cmake . ${{ matrix.additional_arguments }}
@@ -71,6 +71,12 @@ jobs:
           cmake . ${{ matrix.additional_arguments }}
           cmake --build .
 
+      - name: Build windows_raise_widget example with CMake
+        working-directory: examples/windows_raise_widget/
+        run: |
+          cmake . ${{ matrix.additional_arguments }}
+          cmake --build .
+
       - name: Setup MSVC environment for QMake
         uses: ilammy/msvc-dev-cmd@v1
 
@@ -80,7 +86,7 @@ jobs:
           qmake
           ${{ matrix.make }}
 
-      - name: Build calculator example QMake
+      - name: Build calculator example with QMake
         working-directory: examples/calculator/
         run: |
           qmake
@@ -91,3 +97,9 @@ jobs:
         run: |
           qmake
           ${{ matrix.make }}
+
+      - name: Build windows_raise_widget example with QMake
+        working-directory: examples/windows_raise_widget/
+        run: |
+          qmake
+          ${{ matrix.make }}

Windows.md

@@ -7,36 +7,15 @@ application can bring it's primary instance window whenever a second copy
 of the application is started.
 
 On Windows the ability to bring the application windows to the foreground is
-restricted, see [AllowSetForegroundWindow()][https://msdn.microsoft.com/en-us/library/windows/desktop/ms632668.aspx] for more
-details.
+restricted, see [AllowSetForegroundWindow()](https://msdn.microsoft.com/en-us/library/windows/desktop/ms632668.aspx) for more details.
 
 The background process (the primary instance) can bring its windows to the
 foreground if it is allowed by the current foreground process (the secondary
 instance). To bypass this `SingleApplication` must be initialized with the
-`allowSecondary` parameter set to `true` and the `options` parameter must
-include `Mode::SecondaryNotification`, See `SingleApplication::Mode` for more
-details.
+`allowSecondary` parameter set to `true` .
 
-Here is an example:
+If the widget is minimized to Windows task bar, `QWidget::raise()` or
+`QWidget::show()` can not bring it to the front, you have to use Windows API
+`ShowWindow()` .
 
-```cpp
-if( app.isSecondary() ) {
-    // This API requires LIBS += User32.lib to be added to the project
-    AllowSetForegroundWindow( DWORD( app.primaryPid() ) );
-}
-
-if( app.isPrimary() ) {
-    QObject::connect(
-        &app,
-        &SingleApplication::instanceStarted,
-        this,
-        &App::instanceStarted
-    );
-}
-```
-
-```cpp
-void App::instanceStarted() {
-    QApplication::setActiveWindow( [window/widget to set to the foreground] );
-}
-```
+You can find [demo code](examples/windows_raise_widget/main.cpp) in the examples directory.

examples/windows_raise_widget/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.7.0)
+
+project(windows_raise_widget LANGUAGES CXX)
+
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_WIN32_EXECUTABLE TRUE)
+
+# SingleApplication base class
+set(QAPPLICATION_CLASS QApplication)
+add_subdirectory(../.. SingleApplication)
+
+find_package(Qt${QT_DEFAULT_MAJOR_VERSION} COMPONENTS Core Widgets REQUIRED)
+
+add_executable(${PROJECT_NAME} main.cpp)
+
+target_link_libraries(${PROJECT_NAME} SingleApplication::SingleApplication)

examples/windows_raise_widget/main.cpp

@@ -0,0 +1,59 @@
+
+#include <QWidget>
+
+#include "singleapplication.h"
+
+#ifdef Q_OS_WINDOWS
+#include <Windows.h>
+#endif
+
+void raiseWidget(QWidget* widget);
+
+int main(int argc, char *argv[]) {
+
+#ifdef Q_OS_WINDOWS
+    SingleApplication app(argc, argv, true);
+
+    if (app.isSecondary()) {
+
+        AllowSetForegroundWindow( DWORD( app.primaryPid() ) );
+
+        app.sendMessage("RAISE_WIDGET");
+
+        return 0;
+    }
+#else
+    SingleApplication app(argc, argv);
+#endif
+
+    QWidget* widget = new QWidget;
+
+#ifdef Q_OS_WINDOWS
+    QObject::connect(&app, &SingleApplication::receivedMessage,
+                     widget, [widget] () { raiseWidget(widget); } );
+#else
+    QObject::connect(&app, &SingleApplication::instanceStarted,
+                     widget, [widget] () { raiseWidget(widget); } );
+#endif
+
+    widget->show();
+
+    return app.exec();
+}
+
+void raiseWidget(QWidget* widget) {
+#ifdef Q_OS_WINDOWS
+    HWND hwnd = (HWND)widget->winId();
+
+    // check if widget is minimized to Windows task bar
+    if (::IsIconic(hwnd)) {
+        ::ShowWindow(hwnd, SW_RESTORE);
+    }
+
+    ::SetForegroundWindow(hwnd);
+#else
+    widget->show();
+    widget->raise();
+    widget->activateWindow();
+#endif
+}

examples/windows_raise_widget/windows_raise_widget.pro

@@ -0,0 +1,10 @@
+# Single Application implementation
+include(../../singleapplication.pri)
+DEFINES += QAPPLICATION_CLASS=QApplication
+
+QT += widgets
+SOURCES += main.cpp
+
+win32{
+  LIBS += User32.lib
+}