FlexGanttFX Developer Manual : 3.4.3 Event Handling

Introduction

The graphics view fires standard JavaFX events in order to let applications react to change. The concepts used for event handler support in FlexGanttFX are the same as the ones found in the standard JavaFX controls. 

Activity Events

Activity events are fired whenever the user deletes or edits an activity. To receive an activity event simply register an event handler with the graphics view via one of the convenience methods.

GraphicsBase<?> graphics = ganttChart.getGraphics();
graphics.setOnActivityChangeFinished(evt -> System.out.println("An activity has changed"));

If you need to register more than one handler for a specific event type then use this approach:

GraphicsBase<?> graphics = ganttChart.getGraphics();
graphics.addEventHandler(ActivityEvent.ACTIVITY_CHANGE_FINISHED, evt -> System.out.println("Listener 1"));
graphics.addEventHandler(ActivityEvent.ACTIVITY_CHANGE_FINISHED, evt -> System.out.println("Listener 2"));

The following table lists all supported activity event types and the convenience setter methods of the graphics view. These methods are used to quickly register an event handler for the given event type.

ACTIVITY_DELETED

setOnActivityDeleted()

ACTIVITY_CHANGE

setOnActivityChanged()

ACTIVITY_CHANGE_STARTED

ACTIVITY_CHANGE_ONGOING

ACTIVITY_CHANGE_FINISHED

setOnActivityChangeStarted()

setOnActivityChangeOngoing()

setOnActivityChangeFinished()

CHART_HIGH_VALUE_CHANGE_STARTED

CHART_HIGH_VALUE_CHANGE_ONGOING

CHART_HIGH_VALUE_CHANGE_FINISHED

setOnChartHighValueChangeStarted();

setOnChartHighValueChangeOngoing();

setOnChartHighValueChangeFinished();

CHART_LOW_VALUE_CHANGE_STARTED

CHART_LOW_VALUE_CHANGE_ONGOING

CHART_LOW_VALUE_CHANGE_FINISHED

setOnChartLowValueChangeStarted();

setOnChartLowValueChangeOngoing();

setOnChartLowValueChangeFinished();

CHART_VALUE_CHANGE_STARTED

CHART_VALUE_CHANGE_ONGOING

CHART_VALUE_CHANGE_FINISHED

setOnChartValueChangeStarted();

setOnChartValueChangeOngoing();

setOnChartValueChangeFinished();

DRAG_STARTED

DRAG_ONGOING

DRAG_FINISHED

setOnActivityDragStarted();

setOnActivityDragOngoing();

setOnActivityDragFinished();

END_TIME_CHANGE_STARTED

END_TIME_CHANGE_ONGOING

END_TIME_CHANGE_FINISHED

setOnActivityEndTimeChangeStarted();

setOnActivityEndTimeChangeOngoing();

setOnActivityEndTimeChangeFinished();

HORIZONTAL_DRAG_STARTED

HORIZONTAL_DRAG_ONGOING

HORIZONTAL_DRAG_FINISHED

setOnActivityHorizontalDragStarted();

setOnActivityHorizontalDragOngoing();

setOnActivityHorizontalDragFinished();

PERCENTAGE_CHANGE_STARTED

PERCENTAGE_CHANGE_ONGOING

PERCENTAGE_CHANGE_FINISHED

setOnActivityPercentageChangeStarted();

setOnActivityPercentageChangeOngoing();

setOnActivityPercentageChangeFinished();

START_TIME_CHANGE_STARTED

START_TIME_CHANGE_ONGOING

START_TIME_CHANGE_FINISHED

setOnActivityStartTimeChangeStarted();

setOnActivityStartTimeChangeOngoing();

setOnActivityStartTimeChangeFinished();

VERTICAL_DRAG_STARTED

VERTICAL_DRAG_ONGOING

VERTICAL_DRAG_FINISHED

setOnActivityVerticalDragStarted();

setOnActivityVerticalDragOngoing();

setOnActivityVerticalDragFinished();

Activity Events Hierarchy

The event types defined in the ActivityEvent class are defining an event hierarchy. All events are input events (InputEvent.ANY) and they change the activity. Some of them get fired when the user starts the change, some while the change is ongoing, and some when the change is finished. 

• InputEvent.ANY

  • ACTIVITY_CHANGE

    • ACTIVITY_DELETED

    • ACTIVITY_CHANGE_STARTED  // All event types that signal "start"

      • CHART_VALUE_CHANGE_STARTED

        • CHART_HIGH_VALUE_CHANGE_STARTED

        • CHART_LOW_VALUE_CHANGE_STARTED

      • DRAG_STARTED

      • END_TIME_CHANGE_STARTED

      • HORIZONTAL_DRAG_STARTED

      • PERCENTAGE_CHANGE_STARTED

      • START_TIME_CHANGE_STARTED

      • VERTICAL_DRAG_STARTED

    • ACTIVITY_CHANGE_ONGOING // All event types that signal "ongoing"

      • CHART_VALUE_CHANGE_ONGOING

        • CHART_HIGH_VALUE_CHANGE_ONGOING

        • CHART_LOW_VALUE_CHANGE_ONGOING

      • DRAG_ONGOING

      • END_TIME_CHANGE_ONGOING

      • HORIZONTAL_DRAG_ONGOING

      • PERCENTAGE_CHANGE_ONGOING

      • START_TIME_CHANGE_ONGOING

      • VERTICAL_DRAG_ONGOING

    • ACTIVITY_CHANGE_FINISHED // All event types that signal "finished"

      • CHART_VALUE_CHANGE_FINISHED

        • CHART_HIGH_VALUE_CHANGE_FINISHED

        • CHART_LOW_VALUE_CHANGE_FINISHED

      • DRAG_FINISHED

      • END_TIME_CHANGE_FINISHED

      • HORIZONTAL_DRAG_FINISHED

      • PERCENTAGE_CHANGE_FINISHED

      • START_TIME_CHANGE_FINISHED

      • VERTICAL_DRAG_FINISHED

Activity Event Properties

Applications are obviously interested in the attributes of an activity. Not only the new values of these attributes (for example the new start time) but also the old values (start time before the change). The new values are already available on the activity as they are being set while the user performs the change. The old values are stored on the event object. The following table lists the methods on ActivityEvent to retrieve these values.

getOldTime()

END_TIME_CHANGE_

START_TIME_CHANGE_

getOldTimeInterval()

DRAG_

HORIZONTAL_DRAG_

VERTICAL_DRAG_

getOldRow()

DRAG_

VERTICAL_DRAG_

getOldValue()

CHART_VALUE_CHANGE_

CHART_HIGH_VALUE_

CHART_LOW_VALUE_

PERCENTAGE_CHANGE_

Lasso Events

The user can use a lasso to select activities. Events are fired when this happens. To receive a lasso event simply register an event handler with the graphics view via one of the convenience methods.

GraphicsBase<?> graphics = ganttChart.getGraphics();
graphics.setOnLassoFinished(evt -> System.out.println("The lasso was used"));

If you need to register more than one handler for a specific event type then use this approach:

GraphicsBase<?> graphics = ganttChart.getGraphics();
graphics.addEventHandler(LassoEvent.SELECTION_FINISHED, evt -> System.out.println("Listener 1"));
graphics.addEventHandler(LassoEvent.SELECTION_FINISHED, evt -> System.out.println("Listener 2"));

The following table lists the event types and the convenience setter methods of the graphics view.

ALL

setOnLassoSelection()

SELECTION_STARTED

setOnLassoSelectionStarted()

SELECTION_ONGOING

setOnLassoSelectionOngoing()

SELECTION_FINISHED

setOnLassoSelectionFinished()

Lasso Event Hierarchy

 The event types defined in the LassoEvent class are defining an event hierarchy. All events are input events (InputEvent.ANY). 

• InputEvent.ANY

  • LassoEvent.ALL

    • LassoEvent.SELECTION_STARTED

    • LassoEvent.SELECTION_ONGOING

    • LassoEvent.SELECTION_FINISHED

Lasso Info

The lasso automatically performs selections of activities but sometimes we might want to know more about the exact nature of this selection or we want to use the lasso for another use case (e.g. for creating new activities). For this reason instances of LassoEvent also provide an object of type LassoInfo, which carries many attributes that the application can use to react accordingly. The lasso information can be retrieved by calling LassoEvent.getInfo(). The following table lists the attributes of LassoInfo.

List<ActivityRef<?>> getActivities();

Instant getStartTime();

Instant getEndTime();

LocalTime getLocalStartTime();

LocalTime getLocalEndTime();

List<Row<?,?,?>> getRows();

Links / Further Reading

• Oracle JavaFX documentation
• Event handling examples