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

2 files changed, 10 insertions, 1 deletions

diff --git a/native/include/android/input.h b/native/include/android/input.h
index 861ec8b..e196686 100644
--- a/native/include/android/input.h
+++ b/native/include/android/input.h
@@ -215,7 +215,15 @@ enum {
      * tracked from its initial down.  That is, somebody requested that tracking
      * started on the key down and a long press has not caused
      * the tracking to be canceled. */
-    AKEY_EVENT_FLAG_TRACKING = 0x200
+    AKEY_EVENT_FLAG_TRACKING = 0x200,
+
+    /* Set when a key event has been synthesized to implement default behavior
+     * for an event that the application did not handle.
+     * Fallback key events are generated by unhandled trackball motions
+     * (to emulate a directional keypad) and by certain unhandled key presses
+     * that are declared in the key map (such as special function numeric keypad
+     * keys when numlock is off). */
+    AKEY_EVENT_FLAG_FALLBACK = 0x400,
 };
 
 /*
diff --git a/native/include/android/keycodes.h b/native/include/android/keycodes.h
index 5f33ad5..b026a0c 100644
--- a/native/include/android/keycodes.h
+++ b/native/include/android/keycodes.h
@@ -230,6 +230,7 @@ enum {
     AKEYCODE_PROG_GREEN      = 184,
     AKEYCODE_PROG_YELLOW     = 185,
     AKEYCODE_PROG_BLUE       = 186,
+    AKEYCODE_APP_SWITCH      = 187,
 
     // NOTE: If you add a new keycode here you must also add it to several other files.
     //       Refer to frameworks/base/core/java/android/view/KeyEvent.java for the full list.