1.当驱动层添加完成配置后，通过getevent命令查看底层驱动配置的键值
Seoul_TF:/ $ Seoul_TF:/ $ getevent
add device 1: /dev/input/event2
name: "mtk-tpd"
add device 2: /dev/input/event0
name: "ACCDET"
add device 3: /dev/input/event1
name: "mtk-kpd"
/dev/input/event1: 0001 00b7 00000001
/dev/input/event1: 0000 0000 00000000
/dev/input/event1: 0001 00b7 00000000
/dev/input/event1: 0000 0000 000000002
———————————————————————————————————————————
2.添加KL 映射
按键布局文件由 供应商、产品（可能还包括版本）ID 或输入设备名称来确定位置。系统会按顺序查阅以下路径,在以下任一kl文件下添加映射即可：
如果所有文件都没有，系统会默认是去读取/data/system/devices/keylayout/Generic.kl配置
/odm/usr/keylayout/Vendor_XXXX_Product_XXXX_Version_XXXX.kl/vendor/usr/keylayout/Vendor_XXXX_Product_XXXX_Version_XXXX.kl/system/usr/keylayout/Vendor_XXXX_Product_XXXX_Version_XXXX.kl/data/system/devices/keylayout/Vendor_XXXX_Product_XXXX_Version_XXXX.kl/odm/usr/keylayout/Vendor_XXXX_Product_XXXX.kl/vendor/usr/keylayout/Vendor_XXXX_Product_XXXX.kl/system/usr/keylayout/Vendor_XXXX_Product_XXXX.kl/data/system/devices/keylayout/Vendor_XXXX_Product_XXXX.kl/odm/usr/keylayout/DEVICE_NAME.kl/vendor/usr/keylayout/DEVICE_NAME.kl/system/usr/keylayout/DEVICE_NAME.kl/data/system/devices/keylayout/DEVICE_NAME.kl/odm/usr/keylayout/Generic.kl/vendor/usr/keylayout/Generic.kl/system/usr/keylayout/Generic.kl/data/system/devices/keylayout/Generic.kl
由第一步getevent查询 可知此按键是00f9，10进制249，名称可以自定义，这里我命名为 CUSTIOM_KEY，首先需要在/data/system/devices/keylayout/Generic.kl添加红色部分:
....
key 165 MEDIA_PREVIOUS
key 168 MEDIA_REWIND
key 159 MEDIA_FAST_FORWARD
key 183 CUSTIOM_KEY
....
———————————————————————————————————————————
3. 在目录frameworks/native/include/android/keycodes.h文件中
末尾处添加 红色部分：
......
AKEYCODE_THUMBS_UP = 286,
/** Thumbs down key. Apps can use this to let user downvote content. */
AKEYCODE_THUMBS_DOWN = 287,
/** Used to switch current account that is consuming content.
* May be consumed by system to switch current viewer profile. */
AKEYCODE_PROFILE_SWITCH = 288,
/* AI Key */
AKEYCODE_CUSTIOM_KEY = 289
———————————————————————————————————————————
4. 在InputEventLabels.h里面也按顺序添加在最后面
frameworks/native/include/input/InputEventLabels.h
......
DEFINE_KEYCODE(ALL_APPS),
DEFINE_KEYCODE(REFRESH),
DEFINE_KEYCODE(THUMBS_UP),
DEFINE_KEYCODE(THUMBS_DOWN),
DEFINE_KEYCODE(PROFILE_SWITCH),
DEFINE_KEYCODE(CUSTIOM_KEY),
{ nullptr, 0 }
};
———————————————————————————————————————————
5.在KeyEvent.java里面最后依次添加，并把LAST_KEYCODE改为才添加的
红色标记部分
/**
* Key code constant: Used to switch current {@link android.accounts.Account} that is
* consuming content. May be consumed by system to set account globally.
*/
public static final int KEYCODE_PROFILE_SWITCH = 288;
/**
* @hide
*/
public static final int KEYCODE_CUSTIOM_KEY = 289;
@TestApi
public static final int LAST_KEYCODE = KEYCODE_CUSTIOM_KEY;
———————————————————————————————————————————
6.更新api文档
test-current.txt这个API文档也需要同步修改LAST_KEYCODE
frameworks/base/api/test-current.txt
public class KeyEvent extends android.view.InputEvent implements android.os.Parcelable {
method public static String actionToString(int);
method public final void setDisplayId(int);
field public static final int LAST_KEYCODE = 289;
}
———————————————————————————————————————————
7.最后一步在attrs.xml最后面同步添加
frameworks/base/core/res/res/values/attrs.xml
<enum name="KEYCODE_REFRESH" value="285" />
<enum name="KEYCODE_THUMBS_UP" value="286" />
<enum name="KEYCODE_THUMBS_DOWN" value="287" />
<enum name="KEYCODE_PROFILE_SWITCH" value="288" />
<enum name="KEYCODE_CUSTIOM_KEY" value="289" />
</attr>
———————————————————————————————————————————
验证：以上步骤完成
PhoneWindowManager.java里就能收到此按键点击事件了，对事件做对应处理即可
@Override
public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {
.......
// Handle special keys.
switch (keyCode) {
case KeyEvent.KEYCODE_CUSTIOM_KEY:{
.......
break;
}
case KeyEvent.KEYCODE_BACK:{
}
.......
}
注：文中红色标记部分为修改或者添加部分
总结：新的物理按键，要上层收到对应事件，只需要按部就班参照系统按键实现即可，system提供scancode，上层转换为keycode使用。