Doc: Make Qt Gui snippets compilable - textdocument-printing

Task-number: QTBUG-81486
Change-Id: If811ac26eebbd6b3f9fd20e2b3fb29d3be24d1cb
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

src/gui/doc/snippets/snippets.pro

@@ -20,5 +20,6 @@ contains(QT_BUILD_PARTS, tests) {
         textdocument-images \
         textdocument-listitems \
         textdocument-listitemstyles \
-        textdocument-lists
+        textdocument-lists \
+        textdocument-printing
 }

src/gui/doc/snippets/textdocument-printing/main.cpp

@@ -47,11 +47,10 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-
-#include <QtGui>
-
 #include "mainwindow.h"
 
+#include <QApplication>
+
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);

src/gui/doc/snippets/textdocument-printing/mainwindow.cpp

@@ -47,11 +47,15 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-
-#include <QtGui>
-
 #include "mainwindow.h"
 
+#include <QMenu>
+#include <QMenuBar>
+#include <QTextEdit>
+#include <QFileDialog>
+#include <QPrinter>
+#include <QPrintDialog>
+
 MainWindow::MainWindow()
 {
     QMenu *fileMenu = new QMenu(tr("&File"));

src/gui/doc/snippets/textdocument-printing/mainwindow.h

@@ -70,13 +70,14 @@ public slots:
     void openFile();
     void printFile();
     void printPdf();
+    void updateMenus();
 
 private:
-    QAction *printAction;
-    QAction *pdfPrintAction;
+    QAction *printAction = nullptr;
+    QAction *pdfPrintAction = nullptr;
     QString currentFile;
-    QTextEdit *editor;
-    QTextDocument *document;
+    QTextEdit *editor = nullptr;
+    QTextDocument *document = nullptr;
 };
 
 #endif

src/gui/doc/snippets/textdocument-printing/textdocument-printing.pro

@@ -1,3 +1,10 @@
-HEADERS     = mainwindow.h
-SOURCES     = main.cpp \
-              mainwindow.cpp
+TEMPLATE = lib
+TARGET = textdocument-printing
+QT += core gui widgets printsupport
+
+HEADERS = \
+    mainwindow.h
+
+SOURCES = \
+    main.cpp \
+    mainwindow.cpp