饼图的事件处理

Question

I have created a javafx pie chart and want to do something when the user clicks on a slice of the pie. I am following this tutorial:

for (final PieChart.Data data : chart.getData()) {
data.getNode().addEventHandler(MouseEvent.MOUSE_PRESSED,
    new EventHandler<MouseEvent>() {
        @Override public void handle(MouseEvent e) {
            caption.setTranslateX(e.getSceneX());
            caption.setTranslateY(e.getSceneY());
            caption.setText(String.valueOf(data.getPieValue()) + "%");
         }
    });

I am getting these error warnings prior to compile: On the ".addEventHandler"

Bound mismatch: The generic method addEventHandler(EventType<T>, EventHandler<?
superT>) of   type Node is not applicable for the arguments (Integer, new
EventHandler<MouseEvent>  (){}). The inferred type MouseEvent&Event is not a valid 
substitute for the bounded parameter <T extends Event>

On the "EventHandler"

Bound mismatch: The type MouseEvent is not a valid substitute for the bounded parameter  
<T extends Event> of the type EventHandler<T>

Does anyone have any insights into why I am getting these errors?

Answer 1

The addEventHandler() method takes two parameters: one of type T , and one that has a super class T . You gave it an EventHandler and an Integer . Since Integer is not a super class of EventHandler , you get an exception.

My guess is that you're accidentally using Java SE's MouseEvent instead of Java FX's MouseEvent .

Answer 2

I made the following changes to fix the problem, th is is javafx specific.

for (final PieChart.Data data : chart.getData()) {
data.getNode().addEventHandler(javafx.scene.input.MouseEvent.MOUSE_PRESSED,
new EventHandler<javafx.scene.input.MouseEvent>() {
    @Override public void handle(javafx.scene.input.MouseEvent e) {
     }
});