From a1b265c318dbda4a213cec930785b81e4c0f7d2b Mon Sep 17 00:00:00 2001
From: elmot <elmot@vaadin.com>
Date: Fri, 25 Sep 2015 16:40:44 +0300
Subject: Framework documentation IN

Change-Id: I767477c1fc3745f9e1f58075fe30c9ac8da63581
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+---
+title: Shortcut Keys
+order: 5
+layout: page
+---
+
+[[advanced.shortcuts]]
+= Shortcut Keys
+
+Vaadin provides simple ways to define shortcut keys for field components, as
+well as to a default button, and a lower-level generic shortcut API based on
+actions.
+
+A __shortcut__ is an action that is executed when a key or key combination is
+pressed within a specific scope in the UI. The scope can be the entire
+[classname]#UI# or a [classname]#Window# inside it.
+
+[[advanced.shortcuts.defaultbutton]]
+== Shortcut Keys for Default Buttons
+
+You can add a __click shortcut__ to a button to set it as "default" button;
+pressing the defined key, typically Enter, in any component in the scope
+(sub-window or UI) causes a click event for the button to be fired.
+
+You can define a click shortcut with the [methodname]#setClickShortcut()#
+shorthand method:
+
+
+[source, java]
+----
+// Have an OK button and set it as the default button
+Button ok = new Button("OK");
+ok.setClickShortcut(KeyCode.ENTER);
+ok.addStyleName(ValoTheme.BUTTON_PRIMARY);
+----
+
+The [methodname]#setClickShortcut()# is a shorthand method to create, add, and
+manage a [classname]#ClickShortcut#, rather than to add it with
+[methodname]#addShortcutListener()#.
+
+Themes offer special button styles to show that a button is special. In the Valo
+theme, you can use the [literal]#++BUTTON_PRIMARY++# style name. The result can
+be seen in <<figure.advanced.shortcuts.defaultbutton>>.
+
+[[figure.advanced.shortcuts.defaultbutton]]
+.Default Button with Click Shortcut
+image::img/shortcut-defaultbutton.png[]
+
+
+[[advanced.shortcuts.focus]]
+== Field Focus Shortcuts
+
+You can define a shortcut key that sets the focus to a field component (any
+component that inherits [classname]#AbstractField#) by adding a
+[classname]#FocusShortcut# as a shortcut listener to the field.
+
+The constructor of the [classname]#FocusShortcut# takes the field component as
+its first parameter, followed by the key code, and an optional list of modifier
+keys, as listed in <<advanced.shortcuts.keycodes>>.
+
+
+[source, java]
+----
+// A field with Alt+N bound to it
+TextField name = new TextField("Name (Alt+N)");
+name.addShortcutListener(
+        new AbstractField.FocusShortcut(name, KeyCode.N,
+                                        ModifierKey.ALT));
+layout.addComponent(name);
+----
+See the http://demo.vaadin.com/book-examples-vaadin7/book#advanced.shortcut.focus[on-line example, window="_blank"].
+
+You can also specify the shortcut by a shorthand notation, where the shortcut
+key is indicated with an ampersand ( [literal]#++&++#).
+
+
+[source, java]
+----
+// A field with Alt+A bound to it, using shorthand notation
+TextField address = new TextField("Address (Alt+A)");
+address.addShortcutListener(
+        new AbstractField.FocusShortcut(address, "&Address"));
+----
+See the http://demo.vaadin.com/book-examples-vaadin7/book#advanced.shortcut.focus[on-line example, window="_blank"].
+
+This is especially useful for internationalization, so that you can determine
+the shortcut key from the localized string.
+
+
+[[advanced.shortcuts.actions]]
+== Generic Shortcut Actions
+
+Shortcut keys can be defined as __actions__ using the
+[classname]#ShortcutAction# class. It extends the generic [classname]#Action#
+class that is used for example in [classname]#Tree# and [classname]#Table# for
+context menus. Currently, the only classes that accept
+[classname]#ShortcutAction#s are [classname]#Window# and [classname]#Panel#.
+
+To handle key presses, you need to define an action handler by implementing the
+[classname]#Handler# interface. The interface has two methods that you need to
+implement: [methodname]#getActions()# and [methodname]#handleAction()#.
+
+The [methodname]#getActions()# method must return an array of
+[classname]#Action# objects for the component, specified with the second
+parameter for the method, the [parameter]#sender# of an action. For a keyboard
+shortcut, you use a [classname]#ShortcutAction#. The implementation of the
+method could be following:
+
+
+[source, java]
+----
+// Have the unmodified Enter key cause an event
+Action action_ok = new ShortcutAction("Default key",
+        ShortcutAction.KeyCode.ENTER, null);
+
+// Have the C key modified with Alt cause an event
+Action action_cancel = new ShortcutAction("Alt+C",
+        ShortcutAction.KeyCode.C,
+        new int[] { ShortcutAction.ModifierKey.ALT });
+
+Action[] actions = new Action[] {action_cancel, action_ok};
+
+public Action[] getActions(Object target, Object sender) {
+    if (sender == myPanel)
+        return actions;
+
+    return null;
+}
+----
+
+The returned [classname]#Action# array may be static or you can create it
+dynamically for different senders according to your needs.
+
+The constructor of [classname]#ShortcutAction# takes a symbolic caption for the
+action; this is largely irrelevant for shortcut actions in their current
+implementation, but might be used later if implementors use them both in menus
+and as shortcut actions. The second parameter is the key code and the third a
+list of modifier keys, which are listed in <<advanced.shortcuts.keycodes>>.
+
+The following example demonstrates the definition of a default button for a user
+interface, as well as a normal shortcut key, AltC for clicking the
+[guibutton]#Cancel# button.
+
+
+[source, java]
+----
+public class DefaultButtonExample extends CustomComponent
+                                  implements Handler {
+    // Define and create user interface components
+    Panel panel = new Panel("Login");
+    FormLayout formlayout = new FormLayout();
+    TextField username = new TextField("Username");
+    TextField password = new TextField("Password");
+    HorizontalLayout buttons = new HorizontalLayout();
+
+    // Create buttons and define their listener methods.
+    Button ok = new Button("OK", this, "okHandler");
+    Button cancel = new Button("Cancel", this, "cancelHandler");
+
+    // Have the unmodified Enter key cause an event
+    Action action_ok = new ShortcutAction("Default key",
+            ShortcutAction.KeyCode.ENTER, null);
+
+    // Have the C key modified with Alt cause an event
+    Action action_cancel = new ShortcutAction("Alt+C",
+            ShortcutAction.KeyCode.C,
+            new int[] { ShortcutAction.ModifierKey.ALT });
+
+    public DefaultButtonExample() {
+        // Set up the user interface
+        setCompositionRoot(panel);
+        panel.addComponent(formlayout);
+        formlayout.addComponent(username);
+        formlayout.addComponent(password);
+        formlayout.addComponent(buttons);
+        buttons.addComponent(ok);
+        buttons.addComponent(cancel);
+
+        // Set focus to username
+        username.focus();
+
+        // Set this object as the action handler
+        panel.addActionHandler(this);
+    }
+
+    /**
+     * Retrieve actions for a specific component. This method
+     * will be called for each object that has a handler; in
+     * this example just for login panel. The returned action
+     * list might as well be static list.
+     */
+    public Action[] getActions(Object target, Object sender) {
+        System.out.println("getActions()");
+        return new Action[] { action_ok, action_cancel };
+    }
+
+    /**
+     * Handle actions received from keyboard. This simply directs
+     * the actions to the same listener methods that are called
+     * with ButtonClick events.
+     */
+    public void handleAction(Action action, Object sender,
+                             Object target) {
+        if (action == action_ok) {
+            okHandler();
+        }
+        if (action == action_cancel) {
+            cancelHandler();
+        }
+    }
+
+    public void okHandler() {
+        // Do something: report the click
+        formlayout.addComponent(new Label("OK clicked. "
+                + "User=" + username.getValue() + ", password="
+                + password.getValue()));
+    }
+
+    public void cancelHandler() {
+        // Do something: report the click
+        formlayout.addComponent(new Label("Cancel clicked. User="
+                + username.getValue() + ", password="
+                + password.getValue()));
+    }
+}
+----
+
+Notice that the keyboard actions can currently be attached only to
+[classname]#Panel#s and [classname]#Window#s. This can cause problems if you
+have components that require a certain key. For example, multi-line
+[classname]#TextField# requires the Enter key. There is currently no way to
+filter the shortcut actions out while the focus is inside some specific
+component, so you need to avoid such conflicts.
+
+
+[[advanced.shortcuts.keycodes]]
+== Supported Key Codes and Modifier Keys
+
+The shortcut key definitions require a key code to identify the pressed key and
+modifier keys, such as Shift, Alt, or Ctrl, to specify a key combination.
+
+The key codes are defined in the [classname]#ShortcutAction.KeyCode# interface
+and are:
+
+Keys [parameter]#A#to[parameter]#Z#:: Normal letter keys
+[parameter]#F1#to[parameter]#F12#:: Function keys
+
+[parameter]#BACKSPACE#,[parameter]#DELETE#,[parameter]#ENTER#,[parameter]#ESCAPE#,[parameter]#INSERT#,[parameter]#TAB#:: Control keys
+
+[parameter]#NUM0#to[parameter]#NUM9#:: Number pad keys
+
+[parameter]#ARROW_DOWN#,[parameter]#ARROW_UP#,[parameter]#ARROW_LEFT#,[parameter]#ARROW_RIGHT#:: Arrow keys
+
+[parameter]#HOME#,[parameter]#END#,[parameter]#PAGE_UP#,[parameter]#PAGE_DOWN#:: Other movement keys
+
+
+
+Modifier keys are defined in [classname]#ShortcutAction.ModifierKey# and are:
+
+[parameter]#ModifierKey.ALT#:: Alt key
+[parameter]#ModifierKey.CTRL#:: Ctrl key
+[parameter]#ModifierKey.SHIFT#:: Shift key
+
+
+All constructors and methods accepting modifier keys take them as a variable
+argument list following the key code, separated with commas. For example, the
+following defines a CtrlShiftN key combination for a shortcut.
+
+
+[source, java]
+----
+TextField name = new TextField("Name (Ctrl+Shift+N)");
+name.addShortcutListener(
+        new AbstractField.FocusShortcut(name, KeyCode.N,
+                                        ModifierKey.CTRL,
+                                        ModifierKey.SHIFT));
+----
+
+=== Supported Key Combinations
+
+The actual possible key combinations vary greatly between browsers, as most
+browsers have a number of built-in shortcut keys, which can not be used in web
+applications. For example, Mozilla Firefox allows binding almost any key
+combination, while Opera does not even allow binding Alt shortcuts. Other
+browsers are generally in between these two. Also, the operating system can
+reserve some key combinations and some computer manufacturers define their own
+system key combinations.
+
+
+
+
+
-- 
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