add isActive to QgsMapTool and update cursor when it is active

Author: 3nids

python/gui/auto_generated/qgsmaptool.sip.in

@@ -116,6 +116,13 @@ the previously used toolbutton to pop out. *
     QAction *action();
 %Docstring
 Returns associated action with map tool or NULL if no action is associated
+%End
+
+    bool isActive() const;
+%Docstring
+Returns if the current map tool active on the map canvas
+
+.. versionadded:: 3.4
 %End
 
     void setButton( QAbstractButton *button );

src/gui/qgsmaptool.cpp

@@ -130,6 +130,11 @@ QAction *QgsMapTool::action()
   return mAction;
 }
 
+bool QgsMapTool::isActive() const
+{
+  return mCanvas && mCanvas->mapTool() == this;
+}
+
 void QgsMapTool::setButton( QAbstractButton *button )
 {
   mButton = button;
@@ -143,6 +148,8 @@ QAbstractButton *QgsMapTool::button()
 void QgsMapTool::setCursor( const QCursor &cursor )
 {
   mCursor = cursor;
+  if ( isActive() )
+    mCanvas->setCursor( mCursor );
 }
 
 

src/gui/qgsmaptool.h

@@ -137,6 +137,12 @@ class GUI_EXPORT QgsMapTool : public QObject
     //! Returns associated action with map tool or NULL if no action is associated
     QAction *action();
 
+    /**
+     * Returns if the current map tool active on the map canvas
+     * \since QGIS 3.4
+     */
+    bool isActive() const;
+
     /**
      * Use this to associate a button to this maptool. It has the same meaning
      * as setAction() function except it works with a button instead of an QAction. */