Add support for fallback keycodes.

This change enables the framework to synthesize key events to implement
default behavior when an application does not handle a key.
For example, this change enables numeric keypad keys to perform
their associated special function when numlock is off.

The application is informed that it is processing a fallback keypress
so it can choose to ignore it.

Added a new keycode for switching applications.

Added ALT key deadkeys.

New default key mappings:
- ESC -> BACK
- Meta+ESC -> HOME
- Alt+ESC -> MENU
- Meta+Space -> SEARCH
- Meta+Tab -> APP_SWITCH

Fixed some comments.
Fixed some tests.

Change-Id: Id7f3b6645f3a350275e624547822f72652f3defe

1 files changed, 17 insertions, 0 deletions

diff --git a/include/ui/KeyCharacterMap.h b/include/ui/KeyCharacterMap.h
index a1ccb37b048f..10a38109d553 100644
--- a/include/ui/KeyCharacterMap.h
+++ b/include/ui/KeyCharacterMap.h
@@ -44,6 +44,12 @@ public:
         KEYBOARD_TYPE_SPECIAL_FUNCTION = 5,
     };
 
+    // Substitute key code and meta state for fallback action.
+    struct FallbackAction {
+        int32_t keyCode;
+        int32_t metaState;
+    };
+
     ~KeyCharacterMap();
 
     static status_t load(const String8& filename, KeyCharacterMap** outMap);
@@ -67,6 +73,13 @@ public:
      */
     char16_t getCharacter(int32_t keyCode, int32_t metaState) const;
 
+    /* Gets the fallback action to use by default if the application does not
+     * handle the specified key.
+     * Returns true if an action was available, false if none.
+     */
+    bool getFallbackAction(int32_t keyCode, int32_t metaState,
+            FallbackAction* outFallbackAction) const;
+
     /* Gets the first matching Unicode character that can be generated by the key,
      * preferring the one with the specified meta key modifiers.
      * Returns 0 if no matching character is generated.
@@ -155,6 +168,10 @@ private:
 
     KeyCharacterMap();
 
+    bool getKey(int32_t keyCode, const Key** outKey) const;
+    bool getKeyBehavior(int32_t keyCode, int32_t metaState,
+            const Key** outKey, const Behavior** outBehavior) const;
+
     bool findKey(char16_t ch, int32_t* outKeyCode, int32_t* outMetaState) const;
 
     static void addKey(Vector<KeyEvent>& outEvents,