Media with JavaFX - Java 8 Recipes - page 706

Figure 16-5 . Closed caption text
How It Works
The Media API has many event properties to which the developer can attach
EventHandler s or Runnable s instances so they can respond when the events are
triggered. This recipe focused on the OnMarker event property. The Marker prop-
erty is responsible for receiving marker events ( MediaMarkerEvent ).
Let's begin by adding markers to the Media object. It contains a method
getMarkers() that returns an
javafx.collections.ObservableMap<String, Duration> . With an
observable map, you can add key/value pairs that represent each marker. Adding keys
should be a unique identifier, and the value is an instance of Duration . For simpli-
city, this example uses the closed caption text as the key for each media marker. The
marker durations are those written down as users press the pause button at points in the
video determined in Recipe 16-3. Be advised that this is not the recommended ap-
proach to use for production-quality code. You may want to use a parallel Map instead.
After adding markers you will be setting an EventHandler into the Medi-
aPlayer object's OnMarker property using the setOnMarker() method. Next,
you implement an EventHandler via a lambda expression to handle MediaMark-
erEvent s that are raised. Once an event has been received, you obtain the key repres-
enting the text to be used in the closed caption. The instance variable closedCap-
tion ( javafx.scene.text.Text node) will simply be shown by calling the
setText() method with the key or string associated with the marker.