/*******************************************************************************************************************/
转换的过程就是：从驱动层上报的input_event:的code,已powerkey为例：
116,从对应的xxx.kl文件找到对应的行：
key 116 POWER
116对应的 key是POWER
与ＰＯＷＥＲ对应的InputEventLabel是 {POWER, AKEYCODE_POWER}
AKEYCODE_POWER是个枚举类型的变量，对应的值是26.
转换的代码是：
frameworks/native/libs/input/KeyLayoutMap.cpp
从这个代码可以学到cpp是怎样分析文件，从文件中提取信息的。
通过下面的log可以看出：
status_t KeyLayoutMap::Parser::parseKey() －>
int32_t keyCode = getKeyCodeByLabel(keyCodeToken.string());
frameworks/native/include/input/InputEventLabels.h
static int32_t getKeyCodeByLabel(const char* label) {
return int32_t(lookupValueByLabel(label, KEYCODES));
}
frameworks/native/include/input/InputEventLabels.h
#define DEFINE_KEYCODE(key) { #key, AKEYCODE_##key }
struct InputEventLabel {
const char *literal;
int value;
};
static const InputEventLabel KEYCODES[] = {
// 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.
DEFINE_KEYCODE(UNKNOWN),
DEFINE_KEYCODE(SOFT_LEFT),
DEFINE_KEYCODE(SOFT_RIGHT),
}
从这个包含的头文件#include <android/keycodes.h>找到，字符串对应的数值，就是所说的keyCode:
frameworks/native/include/android/keycodes.h
/*
* Key codes.
*/
enum {
AKEYCODE_UNKNOWN = 0,
AKEYCODE_SOFT_LEFT = 1,
AKEYCODE_SOFT_RIGHT = 2,
AKEYCODE_HOME = 3,
AKEYCODE_BACK = 4,
AKEYCODE_CALL = 5,
AKEYCODE_POWER = 26,
}
这个文件和java层的文件：frameworks/base/core/java/android/view/KeyEvent.java对应
/** Key code constant: Power key. */
public static final int KEYCODE_POWER = 26;
/*******************************************************************************************************************/
打开debug开关，可得如下的log:下面的log是创建一个输入设备的过程
08-12 14:19:40.010 1271 2703 E EventHub: Opening device: /dev/input/event2
08-12 14:19:40.011 1271 2703 E EventHub: Created descriptor: raw=:0000:0000:name:qpnp_pon, cooked=fb60d4f4370f5dbe8267b63d38dea852987571ab
08-12 14:19:40.011 1271 2703 E EventHub: add device 3: /dev/input/event2
08-12 14:19:40.011 1271 2703 E EventHub: bus: 0000
08-12 14:19:40.011 1271 2703 E EventHub: vendor 0000
08-12 14:19:40.011 1271 2703 E EventHub: product 0000
08-12 14:19:40.011 1271 2703 E EventHub: version 0000
08-12 14:19:40.011 1271 2703 E EventHub: name: "qpnp_pon"
08-12 14:19:40.011 1271 2703 E EventHub: location: "qpnp_pon/input0"
08-12 14:19:40.011 1271 2703 E EventHub: unique id: ""
08-12 14:19:40.011 1271 2703 E EventHub: descriptor: "fb60d4f4370f5dbe8267b63d38dea852987571ab"
08-12 14:19:40.011 1271 2703 E EventHub: driver: v1.0.1
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system provided input device configuration file: path='/system/usr/idc/qpnp_pon.idc'
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system user input device configuration file: path='/data/system/devices/idc/qpnp_pon.idc'
08-12 14:19:40.011 1271 2703 E InputDevice: Probe failed to find input device configuration file: name='qpnp_pon', type=0
08-12 14:19:40.011 1271 2703 D EventHub: No input device configuration file found for device 'qpnp_pon'.
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system provided input device configuration file: path='/system/usr/keylayout/qpnp_pon.kl'
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system user input device configuration file: path='/data/system/devices/keylayout/qpnp_pon.kl'
08-12 14:19:40.011 1271 2703 E InputDevice: Probe failed to find input device configuration file: name='qpnp_pon', type=1
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/qpnp_pon.kcm'
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system user input device configuration file: path='/data/system/devices/keychars/qpnp_pon.kcm'
08-12 14:19:40.011 1271 2703 E InputDevice: Probe failed to find input device configuration file: name='qpnp_pon', type=2
08-12 14:19:40.011 1271 2703 E InputDevice: Probing for system provided input device configuration file: path='/system/usr/keylayout/Generic.kl'
08-12 14:19:40.011 1271 2703 E InputDevice: Found
08-12 14:19:40.014 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:25: 'key 3 2'.
08-12 14:19:40.014 1271 2703 D KeyLayoutMap: Parsed key scan code: code=3, keyCode=9, flags=0x00000000.
08-12 14:19:40.014 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:26: 'key 4 3'.
08-12 14:19:40.014 1271 2703 D KeyLayoutMap: Parsed key scan code: code=4, keyCode=10, flags=0x00000000.
08-12 14:
08-12 14:19:40.015 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:37: 'key 15 TAB'.
08-12 14:19:40.015 1271 2703 D KeyLayoutMap: Parsed key scan code: code=15, keyCode=61, flags=0x00000000.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:437: 'led 0x06 SUSPEND'.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed led scan code: code=6, ledCode=6.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:438: 'led 0x07 MUTE'.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed led scan code: code=7, ledCode=7.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:439: 'led 0x08 MISC'.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed led scan code: code=8, ledCode=8.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:440: 'led 0x09 MAIL'.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed led scan code: code=9, ledCode=9.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsing /system/usr/keylayout/Generic.kl:441: 'led 0x0a CHARGING'.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed led scan code: code=10, ledCode=10.
08-12 14:19:40.036 1271 2703 D KeyLayoutMap: Parsed key layout map file '/system/usr/keylayout/Generic.kl' 442 lines in 24.518ms.
08-12 14:19:40.036 1271 2703 E InputDevice: Probing for system provided input device configuration file: path='/system/usr/keychars/Generic.kcm'
08-12 14:19:40.036 1271 2703 E InputDevice: Found
08-12 14:19:40.036 1271 1271 I SystemServiceManager: Starting com.android.server.MountService$Lifecycle
08-12 14:19:40.037 1271 2703 W EventHub: Unable to disable kernel key repeat for /dev/input/event2: Function not implemented
08-12 14:19:40.037 1271 2703 I EventHub: New device: id=3, fd=123, path='/dev/input/event2', name='qpnp_pon', classes=0x1, configuration='', keyLayout='/system/usr/keylayout/Generic.kl', keyCharacterMap='/system/usr/keychars/Generic.kcm', builtinKeyboard=false, wakeMechanism=EPOLLWAKEUP, usingClockIoctl=true