Make custom projections dialog a bit more user friendly

...by updating the list immediately when changes are made to the
current projection's name or definition. Previously the list
was only updated when a new item in the list was clicked, but that
made it appear as though the current changes were not applied
immediately and left users looking for a "save" button to actually
lock-in their changes.

By updating the list immediately we make it obvious that the
changes apply immediately and no further action is required (except
for hitting OK on the dialog!)

src/app/qgscustomprojectiondialog.cpp

@@ -185,13 +185,15 @@ QgsCustomProjectionDialog::QgsCustomProjectionDialog( QWidget *parent, Qt::Windo
   populateList();
   if ( !mCustomCRSnames.empty() )
   {
-    leName->setText( mCustomCRSnames[0] );
-    teParameters->setPlainText( mCustomCRSparameters[0] );
+    whileBlocking( leName )->setText( mCustomCRSnames[0] );
+    whileBlocking( teParameters )->setPlainText( mCustomCRSparameters[0] );
     leNameList->setCurrentItem( leNameList->topLevelItem( 0 ) );
   }
 
   leNameList->hideColumn( QgisCrsIdColumn );
 
+  connect( leName, &QLineEdit::textChanged, this, &QgsCustomProjectionDialog::updateListFromCurrentItem );
+  connect( teParameters, &QPlainTextEdit::textChanged, this, &QgsCustomProjectionDialog::updateListFromCurrentItem );
 }
 
 QgsCustomProjectionDialog::~QgsCustomProjectionDialog()
@@ -451,8 +453,8 @@ void QgsCustomProjectionDialog::leNameList_currentItemChanged( QTreeWidgetItem *
   if ( current )
   {
     currentIndex = leNameList->indexOfTopLevelItem( current );
-    leName->setText( mCustomCRSnames[currentIndex] );
-    teParameters->setPlainText( current->text( QgisCrsParametersColumn ) );
+    whileBlocking( leName )->setText( mCustomCRSnames[currentIndex] );
+    whileBlocking( teParameters )->setPlainText( current->text( QgisCrsParametersColumn ) );
   }
   else
   {
@@ -541,6 +543,22 @@ void QgsCustomProjectionDialog::buttonBox_accepted()
   }
 }
 
+void QgsCustomProjectionDialog::updateListFromCurrentItem()
+{
+  QTreeWidgetItem *item = leNameList->currentItem();
+  if ( !item )
+    return;
+
+  int currentIndex = leNameList->indexOfTopLevelItem( item );
+  if ( currentIndex < 0 )
+    return;
+
+  mCustomCRSnames[currentIndex] = leName->text();
+  mCustomCRSparameters[currentIndex] = teParameters->toPlainText();
+  item->setText( QgisCrsNameColumn, leName->text() );
+  item->setText( QgisCrsParametersColumn, teParameters->toPlainText() );
+}
+
 void QgsCustomProjectionDialog::pbnCalculate_clicked()
 {
   // We must check the prj def is valid!

src/app/qgscustomprojectiondialog.h

@@ -43,6 +43,10 @@ class APP_EXPORT QgsCustomProjectionDialog : public QDialog, private Ui::QgsCust
     void leNameList_currentItemChanged( QTreeWidgetItem *current, QTreeWidgetItem *prev );
     void buttonBox_accepted();
 
+  private slots:
+
+    void updateListFromCurrentItem();
+
   private:
 
     //helper functions