Add an interderminant "empty" state for QgsDateTimeEdit

Author: nyalldawson

python/gui/editorwidgets/qgsdatetimeedit.sip

@@ -30,6 +30,10 @@ class QgsDateTimeEdit : QDateTimeEdit
     //! @note if the widget is not configured to accept NULL dates, this will have no effect
     virtual void clear();
 
+    /** Resets the widget to show no value (ie, an "unknown" state).
+     * @note added in QGIS 2.16
+     */
+    void setEmpty();
 
   protected:
     virtual void resizeEvent( QResizeEvent* event );

src/gui/editorwidgets/qgsdatetimeedit.cpp

@@ -28,6 +28,7 @@ QgsDateTimeEdit::QgsDateTimeEdit( QWidget *parent )
     : QDateTimeEdit( parent )
     , mAllowNull( true )
     , mIsNull( true )
+    , mIsEmpty( false )
 {
   mClearButton = new QToolButton( this );
   mClearButton->setIcon( QgsApplication::getThemeIcon( "/mIconClear.svg" ) );
@@ -57,9 +58,9 @@ void QgsDateTimeEdit::setAllowNull( bool allowNull )
 {
   mAllowNull = allowNull;
 
-  mNullLabel->setVisible( mAllowNull && mIsNull );
-  mClearButton->setVisible( mAllowNull && !mIsNull );
-  lineEdit()->setVisible( !mAllowNull || !mIsNull );
+  mNullLabel->setVisible(( mAllowNull && mIsNull ) && !mIsEmpty );
+  mClearButton->setVisible( mAllowNull && ( !mIsNull || mIsEmpty ) );
+  lineEdit()->setVisible(( !mAllowNull || !mIsNull ) && !mIsEmpty );
 }
 
 
@@ -69,6 +70,13 @@ void QgsDateTimeEdit::clear()
   emit dateTimeChanged( QDateTime() );
 }
 
+void QgsDateTimeEdit::setEmpty()
+{
+  mNullLabel->setVisible( false );
+  lineEdit()->setVisible( false );
+  mClearButton->setVisible( mAllowNull );
+}
+
 void QgsDateTimeEdit::mousePressEvent( QMouseEvent* event )
 {
   QRect lerect = rect().adjusted( 0, 0, -spinButtonWidth(), 0 );
@@ -80,6 +88,7 @@ void QgsDateTimeEdit::mousePressEvent( QMouseEvent* event )
 
 void QgsDateTimeEdit::changed( const QDateTime & dateTime )
 {
+  mIsEmpty = false;
   mIsNull = dateTime.isNull();
   mNullLabel->setVisible( mAllowNull && mIsNull );
   mClearButton->setVisible( mAllowNull && !mIsNull );
@@ -98,6 +107,8 @@ int QgsDateTimeEdit::frameWidth() const
 
 void QgsDateTimeEdit::setDateTime( const QDateTime& dateTime )
 {
+  mIsEmpty = false;
+
   // set an undefined date
   if ( !dateTime.isValid() || dateTime.isNull() )
   {
@@ -107,6 +118,7 @@ void QgsDateTimeEdit::setDateTime( const QDateTime& dateTime )
   {
     QDateTimeEdit::setDateTime( dateTime );
     mIsNull = false;
+    changed( dateTime );
   }
 }
 

src/gui/editorwidgets/qgsdatetimeedit.h

@@ -52,6 +52,10 @@ class GUI_EXPORT QgsDateTimeEdit : public QDateTimeEdit
     //! @note if the widget is not configured to accept NULL dates, this will have no effect
     virtual void clear() override;
 
+    /** Resets the widget to show no value (ie, an "unknown" state).
+     * @note added in QGIS 2.16
+     */
+    void setEmpty();
 
   protected:
     virtual void resizeEvent( QResizeEvent* event ) override;
@@ -69,6 +73,7 @@ class GUI_EXPORT QgsDateTimeEdit : public QDateTimeEdit
 
     bool mAllowNull;
     bool mIsNull;
+    bool mIsEmpty;
 
     QLineEdit* mNullLabel;
     QToolButton* mClearButton;