java - 如何更改多个按钮的MouseReleaseEvent？

Question

我试图弄清楚如何一次更改多个按钮的 OnMouseReleaseEvent。该应用程序是一个屏幕钢琴，我想删除释放事件，以便弹奏的音符能够持续，而不是在短按一下后关闭。

我的代码片段适用于一个键:

@FXML
public void changeOnMouseRelease(){
        if (getOriginalEvent() == null) {
            setOriginalEvent(keyC.getOnMouseReleased());
        }
        if (getOriginalEvent() == keyC.getOnMouseReleased()) {
            keyC.setOnMouseReleased(event -> {
                System.out.println("Mouserelease-Event empty \n");
            });
        } else keyC.setOnMouseReleased(getOriginalEvent());
    }
}

这些是原始事件的 getter 和 setter:

private void setOriginalEvent(EventHandler originalEvent){
    this.originalEvent = originalEvent;
}

private EventHandler getOriginalEvent(){
    return this.originalEvent;
}

当我尝试这个时，它不起作用:

@FXML
public void changeOnMouseRelease(){
    for(Button b : pianoKeys) {  // pianoKeys is just an array of the 13 piano buttons
        if (getOriginalEvent() == null) {
            setOriginalEvent(b.getOnMouseReleased());
        }
        if (getOriginalEvent() == b.getOnMouseReleased()) {
            b.setOnMouseReleased(event -> {
                System.out.println("Mouserelease-Event empty \n");
            });
        } else b.setOnMouseReleased(getOriginalEvent());
    }
}

我假设它与 getter/setter 有关，但我不确定如何正确处理这个问题。

Answer 1

通过向事件处理程序添加 MouseEvent 参数，您可以使用此信息来检索按下的 Button。您可以将允许您选择如何处理按键的信息与 Button 关联起来，例如使用用户数据:

Controller

@FXML
private void onMouseReleased(MouseEvent event){
    Button b = (Button) event.getSource();
    System.out.println("released key "+b.getUserData());
}


@FXML
private void onMousePressed(MouseEvent event){
    Button b = (Button) event.getSource();
    System.out.println("pressed key "+b.getUserData());
}

fxml

...
<Button onMousePressed="#onMousePressed" onMouseReleased="#onMouseReleased" userData="D#" />
...

<小时/>

这消除了循环遍历按钮的需要。