Fix track seeking with mouse wheel

src/playlist/playlistview.cpp

@@ -708,7 +708,16 @@ void PlaylistView::mousePressEvent(QMouseEvent *event) {
     return;
   }
 
-  QTreeView::mousePressEvent(event);
+  QModelIndex idx = indexAt(event->pos());
+  if (event->button() == Qt::XButton1 && idx.isValid()) {
+    app_->player()->Previous();
+  }
+  else if (event->button() == Qt::XButton2 && idx.isValid()) {
+    app_->player()->Next();
+  }
+  else {
+    QTreeView::mousePressEvent(event);
+  }
 
   inhibit_autoscroll_ = true;
   inhibit_autoscroll_timer_->start();

src/widgets/trackslider.cpp

@@ -63,6 +63,10 @@ TrackSlider::TrackSlider(QWidget* parent)
   connect(ui_->slider, SIGNAL(sliderMoved(int)), SIGNAL(ValueChanged(int)));
   connect(ui_->slider, SIGNAL(valueChanged(int)), SLOT(ValueMaybeChanged(int)));
   connect(ui_->remaining, SIGNAL(Clicked()), SLOT(ToggleTimeDisplay()));
+  connect(ui_->slider, SIGNAL(SeekForward()), SIGNAL(SeekForward()));
+  connect(ui_->slider, SIGNAL(SeekBackward()), SIGNAL(SeekBackward()));
+  connect(ui_->slider, SIGNAL(Previous()), SIGNAL(Previous()));
+  connect(ui_->slider, SIGNAL(Next()), SIGNAL(Next()));
 
 }
 

src/widgets/trackslider.h

@@ -71,6 +71,11 @@ class TrackSlider : public QWidget {
   void ValueChanged(int value);
   void ValueChangedSeconds(int value);
 
+  void SeekForward();
+  void SeekBackward();
+  void Next();
+  void Previous();
+
  private slots:
   void ValueMaybeChanged(int value);
   void ToggleTimeDisplay();

src/widgets/tracksliderslider.cpp

@@ -70,6 +70,13 @@ void TrackSliderSlider::mousePressEvent(QMouseEvent* e) {
 
 void TrackSliderSlider::mouseReleaseEvent(QMouseEvent* e) {
   QSlider::mouseReleaseEvent(e);
+  if (e->button() == Qt::XButton1) {
+    emit Previous();
+  }
+  else if (e->button() == Qt::XButton2) {
+    emit Next();
+  }
+  e->accept();
 }
 
 void TrackSliderSlider::mouseMoveEvent(QMouseEvent* e) {

src/widgets/tracksliderslider.h

@@ -45,6 +45,8 @@ class TrackSliderSlider : public QSlider {
 signals:
   void SeekForward();
   void SeekBackward();
+  void Previous();
+  void Next();
 
  protected:
   void mousePressEvent(QMouseEvent* e);