如何确定是否触发了控件的Mnemonic/KeyCombination？

Question

我想知道如何确定控件的KeyCombination (通过Mnemonic构造)是否被触发。还是为了简单起见，记忆学的处理程序方法？

基本上，我使用的是从Labeled及其Behavior类扩展的自定义控件，在触发分配的Mnemonic时，我希望执行一些额外的操作。

编辑

因此，在深入研究之后，我想出了一个简单的听KeyEvent的主意(但是请注意，这只是一个想法。不管是哪种情况，我稍后都会想出其他办法的)。下面是操作步骤：

public CustomLabeledBehavior(CustomLabeled control) {
  super(control, ...);

  /* IMPORTANT PART */
  // Assume that mnemonicParsing is set to true
  TextBinding tb = new TextBinding(control.getText());
  KeyCombination kc = tb.getMnemonicKeyCombination();

  control.getScene().addEventFilter(KeyEvent.KEY_PRESSED, e -> {
    if (kc.match(e)) {
      System.out.println("MATCHED!");
    }
  });
}

Answer 1

更新

为了使这个答案比以前更有用，我将向您展示我当前用于确定是否触发KeyCombination的方法的用法。所以我会尽我所能解释每一个细节。

我们只关注使用自定义控件的Mnemonic属性添加一个MnemonicParsing。我们将这个自定义控件称为CustomLabeled，因为基于这个问题，它从Labeled类扩展而来，因此名称是基于它的。然后，我们将在它的Skin类CustomLabeledSkin中工作。

#1初始化控件：

<!-- Assuming that this FXML is already set and is attached to a Scene -->
<CustomLabeled text="_Hello World!" mnemonicParsing="true"/>

#2设置我们的MnemonicHandler

/* These two variables are initialized from the Constructor. */
private KeyCombination kb; // The combination of keys basically, ALT + Shortcut key
private String shortcut; // The shortcut key itself basically, a Letter key

private boolean altDown = false; // Indicator if the user press ALT key

/**
 * This handler is a convenience variable to easily attach
 * and detach to the Scene's event handlers. This is the
 * whole idea to determine whether the KeyCombination is
 * triggered.
 */
private EventHandler<KeyEvent> mnemonicHandler = new EventHandler<KeyEvent>() {
  @Override
  public void handle(KeyEvent event) {
    // The KeyCombination, basically, the ALT + Shortcut key.
    if (kb.match(event) {
      // TODO: Execute command here.
      event.consume(); // Prevent from further propagation.
      return; // Make sure that the rest won't be executed.
    }
    // While these two functions are for separate event.
    // Example, pressing ALT first before the Shortcut key.
    if (event.isAltDown()) altDown = !altDown;
    if (altDown && event.getCode() == KeyCode.getKeyCode(shortcut)) {
      // TODO: Execute command here.
      event.consume();
    }
  }
}

#3初始化我们的皮肤类：

/**
 * Constructor
 */
public CustomLabeledSkin(CustomLabeled control) {
  // Since this is just an example/testing, we will only assume
  // that MnemonicParsing is enabled and a valid Mnemonic is
  // registered. So if you want to validate a mnemonic, you
  // might want to do it here.
  TextBinding tb = new TextBinding(control.getText());
  kc = tb.getMnemonicKeyCombination();
  shortcut = tb.getMnemonic();

  // Then we can just filter for a KEY_PRESS from the Scene, then
  // everything else will be handled by our MnemonicHandler.
  control.getScene().addEventFilter(KeyEvent.KEY_PRESSED, mnemonicHandler);
}

注意：-- TextBinding类不是公共API的一部分，它被Labeled节点用来处理助记符。

此外，如果当前没有指定的助记符，您可以创建一个方法来分离MnemonicHandler (例如，以前有一个助记符，然后代码被更改.)。