Add feedback of failing to start the client

plus, make setRequiringOutput() matched in PM3Process::connectPM3()

src/ui/mainwindow.cpp

@@ -195,6 +195,14 @@ void MainWindow::on_PM3_connectButton_clicked()
     envSetProcess.kill();
 }
 
+void MainWindow::onPM3ErrorOccurred(QProcess::ProcessError error)
+{
+    qDebug() << "PM3 Error:" << error << pm3->errorString();
+    if(error == QProcess::FailedToStart)
+        QMessageBox::information(this, tr("Info"), tr("Failed to start the client"));
+
+}
+
 void MainWindow::onPM3StateChanged(bool st, const QString& info)
 {
     pm3state = st;
@@ -1093,6 +1101,7 @@ void MainWindow::signalInit()
     connect(this, &MainWindow::reconnectPM3, pm3, &PM3Process::reconnectPM3);
     connect(pm3, &PM3Process::PM3StatedChanged, this, &MainWindow::onPM3StateChanged);
     connect(pm3, &PM3Process::PM3StatedChanged, util, &Util::setRunningState);
+    connect(pm3, &PM3Process::errorOccurred, this, &MainWindow::onPM3ErrorOccurred);
     connect(this, &MainWindow::killPM3, pm3, &PM3Process::killPM3);
     connect(this, &MainWindow::setProcEnv, pm3, &PM3Process::setProcEnv);
     connect(this, &MainWindow::setWorkingDir, pm3, &PM3Process::setWorkingDir);

src/ui/mainwindow.h

@@ -60,6 +60,7 @@ public slots:
     void MF_onMFCardTypeChanged(int id, bool st);
     void on_Raw_keyPressed(QObject *obj_addr, QEvent &event);
     void on_MF_keyWidget_resized(QObject *obj_addr, QEvent &event);
+    void onPM3ErrorOccurred(QProcess::ProcessError error);
 private slots:
 
     void on_PM3_connectButton_clicked();