Fix UserOperationLog crash problem.

src/components/SlidePickerBox.cpp

@@ -105,6 +105,11 @@ void SlidePickerBox::mouseReleaseEvent(QMouseEvent *ev) {
 }
 
 void SlidePickerBox::adjustPosition() const {
+    if(mSelectedLbl == nullptr)
+    {
+        return;
+    }
+
     if (mSelectedLbl->geometry().center().y() != LABEL_CENTER_Y)
     {
         //选择完毕，选中项回归正位
@@ -140,7 +145,10 @@ void SlidePickerBox::setItems(const QStringList& itemsList) {
         lbl->move(p);
     }
     mSelectedIndex = mLabels.count() - 1;
+    if(!mItems.isEmpty())
+    {
         setSelectedValue(this->mItems.last());
+    }
 }
 
 QString SlidePickerBox::getSelectedValue() {
@@ -198,8 +206,11 @@ void SlidePickerBox::setSelectedValue(const QString& val) {
         mLabels[i]->setStyleSheet("background:transparent");
 
     }
+    if(mSelectedIndex >= 0)
+    {
         mSelectedLbl = mLabels[mSelectedIndex];
         mLabels[mSelectedIndex]->setStyleSheet("color:white");
+    }
     adjustPosition();
 }