android kl 檔案的作用【轉】

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本文轉載自：http://blog.csdn.net/u013308744/article/details/49274069

首先看touchscreen的kl檔案


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key 158     BACK              VIRTUAL WAKE
key 102     HOME              VIRTUAL WAKE
key 580     APP_SWITCH        VIRTUAL WAKE
key 116     GESTURE_DOUBLE_CLICK             VIRTUAL WAKE
key 46      GESTURE_C                 VIRTUAL WAKE
key 18      GESTURE_E                 VIRTUAL WAKE
key 31      GESTURE_S                 VIRTUAL WAKE
key 47      GESTURE_V                 VIRTUAL WAKE
key 17      GESTURE_W                 VIRTUAL WAKE
key 44      GESTURE_Z                 VIRTUAL WAKE





那麼這個kl有啥用呢，眾所周知，android kernel和framework是不同的兩層，也就是說，kernel裡認識的
key值是158之類的這種數字，這個158是scankode，它往framework上報的時候也只會報這樣的數字，但是framework不認識這個數字是什麼，所以framework需要先解析kl檔案，map起來，這樣kernel傳值上來的時候才會知道到底是什麼key，也就是說轉換scancode 158變成KeyCodeLabel也就是BACK，然後back再轉換成4這個keycode

首先

key 580     APP_SWITCH        VIRTUAL WAKE

這裡的580是scancode，轉換撐了APP_SWITCH這個keycodelabel

InputEventLabels.h裡的

 DEFINE_KEYCODE(APP_SWITCH),

#define DEFINE_KEYCODE(key) { #key, AKEYCODE_##key }

這裡拼接了AKEYCODE_APP_SWITCH

 

Keycodes.h (native\include\android):    AKEYCODE_APP_SWITCH      = 187,
KeyEvent.java (base\core\java\android\view):    public static final int KEYCODE_APP_SWITCH      = 187;

然後就變成了keycode 187

android kl 檔案的作用【轉】