Fix potential GUI instability due to GUI elements being called in worker

thread (thanks @maxnet) - see comments on 5d4d793 for details.

Author: Rob-Bishop

output

@@ -185,13 +185,12 @@ bool InitDriveThread::method_resizePartitions()
 
         // Warn user that their SD card does not have an MBR and ask
         // if they would like us to create one for them
-        QMessageBox msgBox;
-        msgBox.setWindowTitle("Error: No MBR present on SD Card");
-        msgBox.setText("Would you like NOOBS to create one for you?\nWARNING: This will erase all data on your SD card");
-        msgBox.setStandardButtons(QMessageBox::Yes);
-        msgBox.setDefaultButton(QMessageBox::No);
+        QMessageBox::StandardButton answer;
+        emit query(tr("Would you like NOOBS to create one for you?\nWARNING: This will erase all data on your SD card"),
+                   tr("Error: No MBR present on SD Card"),
+                   &answer);
 
-        if(msgBox.exec() == QMessageBox::Yes)
+        if(answer == QMessageBox::Yes)
         {
 
             emit statusUpdate(tr("Zeroing partition table"));

recovery/initdrivethread.cpp

@@ -11,6 +11,7 @@
  */
 
 #include <QThread>
+#include <QMessageBox>
 #include "config.h"
 
 class InitDriveThread : public QThread
@@ -42,7 +43,7 @@ class InitDriveThread : public QThread
     void error(const QString &msg);
     void statusUpdate(const QString &msg);
     void completed();
-
+    void query(const QString &msg, const QString &title, QMessageBox::StandardButton* answer);
 
 public slots:
 

recovery/initdrivethread.h

@@ -71,6 +71,9 @@ MainWindow::MainWindow(QString *currentLangCode, QSplashScreen *splash, Language
         connect(idt, SIGNAL(statusUpdate(QString)), _qpd, SLOT(setLabelText(QString)));
         connect(idt, SIGNAL(completed()), _qpd, SLOT(deleteLater()));
         connect(idt, SIGNAL(error(QString)), this, SLOT(onError(QString)));
+        connect(idt, SIGNAL(query(QString, QString, QMessageBox::StandardButton*)),
+                this, SLOT(onQuery(QString, QString, QMessageBox::StandardButton*)),
+                Qt::BlockingQueuedConnection);
 
         idt->start();
         _qpd->exec();
@@ -321,6 +324,13 @@ void MainWindow::onError(const QString &msg)
     setEnabled(true);
 }
 
+void MainWindow::onQuery(const QString &msg, const QString &title, QMessageBox::StandardButton* answer)
+{
+    _qpd->hide();
+    *answer = QMessageBox::question(this, title, msg, QMessageBox::Yes|QMessageBox::No);
+    setEnabled(true);
+}
+
 void MainWindow::on_list_currentRowChanged()
 {
     ui->actionWrite_image_to_disk->setEnabled(true);

recovery/mainwindow.cpp

@@ -14,6 +14,7 @@
 #include <QMainWindow>
 #include <QModelIndex>
 #include <QSplashScreen>
+#include <QMessageBox>
 
 namespace Ui {
 class MainWindow;
@@ -58,6 +59,7 @@ protected slots:
     /* Events from ImageWriterThread */
     void onError(const QString &msg);
     void onCompleted();
+    void onQuery(const QString &msg, const QString &title, QMessageBox::StandardButton* answer);
 
 private slots:
     /* UI events */