Examples: request Android storage permissions when using QStandardPaths

http example uses QStandardPaths, on Android permissions might need to
be explicitly requested to write the downloaded file.

Task-number: QTBUG-80717
Change-Id: Icd377254ad77cac661c5ae37e9081e0463493d8b
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

examples/network/http/http.pro

@@ -1,4 +1,8 @@
 QT += network widgets
+android: qtHaveModule(androidextras) {
+    QT += androidextras
+    DEFINES += REQUEST_PERMISSIONS_ON_ANDROID
+}
 
 HEADERS += httpwindow.h
 SOURCES += httpwindow.cpp \

examples/network/http/main.cpp

@@ -53,11 +53,30 @@
 #include <QScreen>
 
 #include "httpwindow.h"
+#ifdef REQUEST_PERMISSIONS_ON_ANDROID
+#include <QtAndroid>
+
+bool requestStoragePermission() {
+    using namespace QtAndroid;
+
+    QString permission = QStringLiteral("android.permission.WRITE_EXTERNAL_STORAGE");
+    const QHash<QString, PermissionResult> results = requestPermissionsSync(QStringList({permission}));
+    if (!results.contains(permission) || results[permission] == PermissionResult::Denied) {
+        qWarning() << "Couldn't get permission: " << permission;
+        return false;
+    }
+
+    return true;
+}
+#endif
 
 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
-
+#ifdef REQUEST_PERMISSIONS_ON_ANDROID
+    if (!requestStoragePermission())
+        return -1;
+#endif
     HttpWindow httpWin;
     const QRect availableSize = httpWin.screen()->availableGeometry();
     httpWin.resize(availableSize.width() / 5, availableSize.height() / 5);