MythZoneMinder: fix Coverity ID 1026721 Unchecked dynamic_cast

In ZMPlayer::keyPressEvent(): Dynamic_cast may fail and return null if the
type cast is incompatible.

This is a false positive because Create() has already checked those widgets
exist and would fail if they didn't long before we get to this code.

mythplugins/mythzoneminder/mythzoneminder/zmplayer.cpp

@@ -37,7 +37,8 @@ using namespace std;
 ZMPlayer::ZMPlayer(MythScreenStack *parent, const char *name,
                    vector<Event *> *eventList, int *currentEvent)
          :MythScreenType(parent, name),
-          m_frameImage(NULL), m_noEventsText(NULL), m_eventText(NULL),
+          m_activeFrameImage(NULL), m_frameImageFS(NULL), m_frameImage(NULL),
+          m_noEventsText(NULL), m_eventText(NULL),
           m_cameraText(NULL), m_frameText(NULL), m_dateText(NULL),
           m_playButton(NULL), m_deleteButton(NULL), m_nextButton(NULL),
           m_prevButton(NULL), m_currentEvent(currentEvent),
@@ -76,11 +77,7 @@ bool ZMPlayer::Create(void)
 
     bool err = false;
 
-    // hide the fullscreen image
-    UIUtilE::Assign(this, m_frameImage,   "framefsimage", &err);
-    if (m_frameImage)
-        m_frameImage->SetVisible(false);
-
+    UIUtilE::Assign(this, m_frameImageFS, "framefsimage", &err);
     UIUtilE::Assign(this, m_frameImage,   "frameimage", &err);
     UIUtilE::Assign(this, m_noEventsText, "noevents_text", &err);
     UIUtilE::Assign(this, m_eventText,    "event_text", &err);
@@ -123,6 +120,10 @@ bool ZMPlayer::Create(void)
         connect(m_nextButton, SIGNAL(Clicked()), this, SLOT(nextPressed()));
     }
 
+    // hide the fullscreen image
+    m_frameImageFS->SetVisible(false);
+    m_activeFrameImage = m_frameImage;
+
     BuildFocusList();
 
     SetFocusWidget(m_playButton);
@@ -144,8 +145,8 @@ void ZMPlayer::getEventInfo()
         if (m_noEventsText)
             m_noEventsText->SetVisible(true);
 
-        m_frameImage->SetFilename(QString("mz_black.png"));
-        m_frameImage->Load();
+        m_activeFrameImage->SetFilename(QString("mz_black.png"));
+        m_activeFrameImage->Load();
 
         m_eventText->Reset();
         m_cameraText->Reset();
@@ -250,15 +251,15 @@ bool ZMPlayer::keyPressEvent(QKeyEvent *event)
                 {
                     m_fullScreen = false;
                     m_frameImage->SetVisible(false);
-                    m_frameImage = dynamic_cast<MythUIImage *> (GetChild("frameimage"));
-                    m_frameImage->SetVisible(true);
+                    m_frameImageFS->SetVisible(true);
+                    m_activeFrameImage = m_frameImageFS;
                 }
                 else
                 {
                     m_fullScreen = true;
-                    m_frameImage->SetVisible(false);
-                    m_frameImage = dynamic_cast<MythUIImage *> (GetChild("framefsimage"));
+                    m_frameImageFS->SetVisible(false);
                     m_frameImage->SetVisible(true);
+                    m_activeFrameImage = m_frameImage;
                 }
 
                 if (!m_paused)
@@ -392,7 +393,7 @@ void ZMPlayer::getFrame(void)
 
         if (m_image)
         {
-            m_frameImage->SetImage(m_image);
+            m_activeFrameImage->SetImage(m_image);
             m_frameText->SetText(QString("%1/%2").arg(m_curFrame).arg(m_lastFrame));
         }
 

mythplugins/mythzoneminder/mythzoneminder/zmplayer.h

@@ -54,6 +54,8 @@ class ZMPlayer : public MythScreenType
 
     void stopPlayer(void);
 
+    MythUIImage      *m_activeFrameImage;
+    MythUIImage      *m_frameImageFS;
     MythUIImage      *m_frameImage;
 
     MythUIText       *m_noEventsText;