Merge pull request #292 from JordanMartinez/addOverrideBehaviorDemo

richtextfx-demos/src/main/java/org/fxmisc/richtext/demo/OverrideBehaviorDemo.java

@@ -0,0 +1,98 @@
+package org.fxmisc.richtext.demo;
+
+import static javafx.scene.input.KeyCode.*;
+import static javafx.scene.input.KeyCombination.*;
+import static org.fxmisc.wellbehaved.event.EventPattern.*;
+
+import javafx.application.Application;
+import javafx.event.Event;
+import javafx.event.EventHandler;
+import javafx.geometry.Insets;
+import javafx.scene.Scene;
+import javafx.scene.control.CheckBox;
+import javafx.scene.control.Label;
+import javafx.scene.input.KeyEvent;
+import javafx.scene.input.MouseEvent;
+import javafx.scene.layout.VBox;
+import javafx.stage.Stage;
+
+import org.fxmisc.richtext.InlineCssTextArea;
+import org.fxmisc.wellbehaved.event.InputMap;
+import org.fxmisc.wellbehaved.event.Nodes;
+
+/**
+ * This demo shows how to override the default behavior of a StyledTextArea via an InputMap.
+ * It also demonstrates the bugs that can arise if one adds a handler to one of the
+ * {@code on[EventType]Property}.
+ */
+public class OverrideBehaviorDemo extends Application {
+
+    public static void main(String[] args) {
+        launch(args);
+    }
+
+    @Override
+    public void start(Stage primaryStage) {
+        InlineCssTextArea area = new InlineCssTextArea();
+
+        InputMap<Event> preventSelectionOrRightArrowNavigation = InputMap.consume(
+                anyOf(
+                        // prevent selection via (CTRL + ) SHIFT + [LEFT, UP, DOWN]
+                        keyPressed(LEFT,    SHIFT_DOWN, SHORTCUT_ANY),
+                        keyPressed(KP_LEFT, SHIFT_DOWN, SHORTCUT_ANY),
+                        keyPressed(UP,    SHIFT_DOWN, SHORTCUT_ANY),
+                        keyPressed(KP_UP, SHIFT_DOWN, SHORTCUT_ANY),
+                        keyPressed(DOWN,    SHIFT_DOWN, SHORTCUT_ANY),
+                        keyPressed(KP_DOWN, SHIFT_DOWN, SHORTCUT_ANY),
+
+                        // prevent selection via mouse events
+                        eventType(MouseEvent.MOUSE_DRAGGED),
+                        eventType(MouseEvent.DRAG_DETECTED),
+                        mousePressed().unless(e -> e.getClickCount() == 1 && !e.isShiftDown()),
+
+                        // prevent any right arrow movement, regardless of modifiers
+                        keyPressed(RIGHT,     SHORTCUT_ANY, SHIFT_ANY),
+                        keyPressed(KP_RIGHT,  SHORTCUT_ANY, SHIFT_ANY)
+                )
+        );
+        Nodes.addInputMap(area, preventSelectionOrRightArrowNavigation);
+
+        area.replaceText(String.join("\n",
+                "You can't move the caret to the right via the RIGHT arrow key in this area.",
+                "Additionally, you cannot select anything either",
+                "",
+                ":-p"
+        ));
+        area.moveTo(0);
+
+        CheckBox addExtraEnterHandlerCheckBox = new CheckBox("Temporarily add an EventHandler to area's `onKeyPressedProperty`?");
+        addExtraEnterHandlerCheckBox.setStyle("-fx-font-weight: bold;");
+
+        Label checkBoxExplanation = new Label(String.join("\n",
+                "The added handler will insert a newline character at the caret's position when [Enter] is pressed.",
+                "If checked, the default behavior and added handler will both occur: ",
+                "\tthus, two newline characters should be inserted when user presses [Enter].",
+                "When unchecked, the handler will be removed."
+        ));
+        checkBoxExplanation.setWrapText(true);
+
+        EventHandler<KeyEvent> insertNewlineChar = e -> {
+            if (e.getCode().equals(ENTER)) {
+                area.insertText(area.getCaretPosition(), "\n");
+                e.consume();
+            }
+        };
+        addExtraEnterHandlerCheckBox.selectedProperty().addListener(
+                (obs, ov, isSelected) -> area.setOnKeyPressed( isSelected ? insertNewlineChar : null)
+        );
+
+        VBox vbox = new VBox(area, addExtraEnterHandlerCheckBox, checkBoxExplanation);
+        vbox.setSpacing(10);
+        vbox.setPadding(new Insets(10));
+
+        primaryStage.setScene(new Scene(vbox, 700, 350));
+        primaryStage.show();
+        primaryStage.setTitle("An area whose behavior has been overridden permanently and temporarily!");
+    }
+
+}