Fix open kmail when we click on button

agents/newmailnotifier/CMakeLists.txt

@@ -46,6 +46,7 @@ target_link_libraries( akonadi_newmailnotifier_agent
   KF5::Notifications
   KF5::Service
   KF5::I18n
+  KF5::KIOGui
 )
 
 if(Qt5TextToSpeech_FOUND)

agents/newmailnotifier/newmailnotifiershowmessagejob.cpp

@@ -6,8 +6,10 @@
 
 #include "newmailnotifiershowmessagejob.h"
 #include "newmailnotifier_debug.h"
+#include <KIO/ApplicationLauncherJob>
 #include <KLocalizedString>
 
+#include <KService>
 #include <QDBusConnection>
 #include <QDBusConnectionInterface>
 #include <QDBusInterface>
@@ -27,24 +29,27 @@ void NewMailNotifierShowMessageJob::start()
         emitResult();
         return;
     }
-    const QString kmailInterface = QStringLiteral("org.kde.kmail");
-    QDBusReply<bool> reply = QDBusConnection::sessionBus().interface()->isServiceRegistered(kmailInterface);
-    if (!reply.isValid() || !reply.value()) {
-        // Program is not already running, so start it
-        QString errmsg;
-        if (!QDBusConnection::sessionBus().interface()->startService(QStringLiteral("org.kde.kmail2")).isValid()) {
-            qCDebug(NEWMAILNOTIFIER_LOG) << " Can not start kmail";
-            setError(UserDefinedError);
-            setErrorText(i18n("Unable to start KMail application."));
-            emitResult();
-            return;
-        }
-    }
-    QDBusInterface kmail(kmailInterface, QStringLiteral("/KMail"), QStringLiteral("org.kde.kmail.kmail"));
-    if (kmail.isValid()) {
-        kmail.call(QStringLiteral("showMail"), mId);
-    } else {
-        qCWarning(NEWMAILNOTIFIER_LOG) << "Impossible to access to DBus interface";
+
+    // start the kmail application if it isn't running yet
+    const auto service = KService::serviceByDesktopName(QStringLiteral("org.kde.kmail2"));
+    if (!service) {
+        qCDebug(NEWMAILNOTIFIER_LOG) << " Can not start kmail";
+        setError(UserDefinedError);
+        setErrorText(i18n("Unable to start KMail application."));
+        emitResult();
+        return;
     }
-    emitResult();
+
+    auto job = new KIO::ApplicationLauncherJob(service, this);
+    connect(job, &KJob::finished, this, [this]() {
+        const QString kmailInterface = QStringLiteral("org.kde.kmail");
+        QDBusInterface kmail(kmailInterface, QStringLiteral("/KMail"), QStringLiteral("org.kde.kmail.kmail"));
+        if (kmail.isValid()) {
+            kmail.call(QStringLiteral("showMail"), mId);
+        } else {
+            qCWarning(NEWMAILNOTIFIER_LOG) << "Impossible to access to DBus interface";
+        }
+        emitResult();
+    });
+    job->start();
 }