[Hi3751V811][Android8.0]系统按键的转换 - android键值的映射
| 平台 | 内核版本 | 安卓版本 |
|---|---|---|
| Hi3751V811 | Linux4.1 | Android8.0 |
系统键值是通用的，其知识点是通用的，因此通过本次学习可以举一反三。
文章目录
- getEvents
- 定义 linux 键值和对应的键名字符串
- 定义<键名>字符串和`android`的`java`层键值对应关系
- 定位`linux`到`android`键转换映射文件
- 查询返回`android`的`java`键值
getEvents
首先getEvents:
文件目录：android/frameworks/native/services/inputflinger/EventHub.cpp
size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSize) {
getEvents()
->scanDevicesLocked()
->scanDirLocked()
->openDeviceLocked()
->loadKeyMapLocked()
->keyMap.load()
->KeyMap::probeKeyMap
->KeyMap::loadKeyLayout
定义 linux 键值和对应的键名字符串
文件目录：/android/device/hisilicon/bigfish/prebuilts/Vendor_0001_Product_0001.kl
...
key 102 HOME
key 103 DPAD_UP
key 104 PAGE_UP
key 105 DPAD_LEFT
key 106 DPAD_RIGHT
key 107 MOVE_END
...
定义<键名>字符串和android的java层键值对应关系
文件目录：/home/nova/hisi/android/frameworks/native/include/android/keycodes.h
/*
* Key codes.
*/
enum {
AKEYCODE_FOCUS = 80,
/** '+' key. */
AKEYCODE_PLUS = 81,
/** Menu key. */
AKEYCODE_MENU = 82,
...
AKEYCODE_MUTE = 91,
/** Page Up key. */
AKEYCODE_PAGE_UP = 92,
/** Page Down key. */
AKEYCODE_PAGE_DOWN = 93,
...
}
定位linux到android键转换映射文件
文件目录：hisi/android/frameworks/native/libs/input/Keyboard.cpp
- 提供函数
loadKeyLayout和getPath，定位linux到android键第一转换映射文件Vendor_0001_Product_0001.kl
status_t KeyMap::loadKeyLayout(const InputDeviceIdentifier& deviceIdentifier,
const String8& name) {
String8 path(getPath(deviceIdentifier, name,
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_LAYOUT));
if (path.isEmpty()) {
return NAME_NOT_FOUND;
}
//打开
status_t status = KeyLayoutMap::load(path, &keyLayoutMap);
if (status) {
return status;
}
keyLayoutFile.setTo(path);
return OK;
}
其中INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_LAYOUT为：/android/frameworks/native/include/input/InputDevice.h
/* Types of input device configuration files. */
enum InputDeviceConfigurationFileType {
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_CONFIGURATION = 0, /* .idc file */
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_LAYOUT = 1, /* .kl file */
INPUT_DEVICE_CONFIGURATION_FILE_TYPE_KEY_CHARACTER_MAP = 2, /* .kcm file */
};
如下：这里才确定path为：/system/usr/keylayout/Vendor_0001_Product_0001.kl
String8 KeyMap::getPath(const InputDeviceIdentifier& deviceIdentifier,
const String8& name, InputDeviceConfigurationFileType type) {
return name.isEmpty()
? getInputDeviceConfigurationFilePathByDeviceIdentifier(deviceIdentifier, type)
: getInputDeviceConfigurationFilePathByName(name, type);
}
其中KeyLayoutMap::load加载并解析函数定义如下：
文件目录：android/frameworks/native/libs/input/KeyLayoutMap.cpp
status_t KeyLayoutMap::load(const String8& filename, sp<KeyLayoutMap>* outMap) {
outMap->clear();
Tokenizer* tokenizer;
status_t status = Tokenizer::open(filename, &tokenizer);
if (status) {
ALOGE("Error %d opening key layout map file %s.", status, filename.string());
} else {
sp<KeyLayoutMap> map = new KeyLayoutMap();
if (!map.get()) {
ALOGE("Error allocating key layout map.");
status = NO_MEMORY;
} else {
#if DEBUG_PARSER_PERFORMANCE
nsecs_t startTime = systemTime(SYSTEM_TIME_MONOTONIC);
#endif
Parser parser(map.get(), tokenizer);
status = parser.parse();
#if DEBUG_PARSER_PERFORMANCE
nsecs_t elapsedTime = systemTime(SYSTEM_TIME_MONOTONIC) - startTime;
ALOGD("Parsed key layout map file '%s' %d lines in %0.3fms.",
tokenizer->getFilename().string(), tokenizer->getLineNumber(),
elapsedTime / 1000000.0);
#endif
if (!status) {
*outMap = map;
}
}
delete tokenizer;
}
return status;
}
其中重点：parser.parse()
status_t KeyLayoutMap::Parser::parse() {
while (!mTokenizer->isEof()) {
#if DEBUG_PARSER
ALOGD("Parsing %s: '%s'.", mTokenizer->getLocation().string(),
mTokenizer->peekRemainderOfLine().string());
#endif
mTokenizer->skipDelimiters(WHITESPACE);
if (!mTokenizer->isEol() && mTokenizer->peekChar() != '#') {
String8 keywordToken = mTokenizer->nextToken(WHITESPACE);
if (keywordToken == "key") {
mTokenizer->skipDelimiters(WHITESPACE);
status_t status = parseKey();
if (status) return status;
} else if (keywordToken == "axis") {
mTokenizer->skipDelimiters(WHITESPACE);
status_t status = parseAxis();
if (status) return status;
} else if (keywordToken == "led") {
mTokenizer->skipDelimiters(WHITESPACE);
status_t status = parseLed();
if (status) return status;
} else {
ALOGE("%s: Expected keyword, got '%s'.", mTokenizer->getLocation().string(),
keywordToken.string());
return BAD_VALUE;
}
mTokenizer->skipDelimiters(WHITESPACE);
if (!mTokenizer->isEol() && mTokenizer->peekChar() != '#') {
ALOGE("%s: Expected end of line or trailing comment, got '%s'.",
mTokenizer->getLocation().string(),
mTokenizer->peekRemainderOfLine().string());
return BAD_VALUE;
}
}
mTokenizer->nextLine();
}
return NO_ERROR;
}
其中重点parseKey()解析Vendor_0001_Product_0001.kl得到linux层code:
status_t KeyLayoutMap::Parser::parseKey() {
String8 codeToken = mTokenizer->nextToken(WHITESPACE);
bool mapUsage = false;
if (codeToken == "usage") {
mapUsage = true;
mTokenizer->skipDelimiters(WHITESPACE);
codeToken = mTokenizer->nextToken(WHITESPACE);
}
char* end;
int32_t code = int32_t(strtol(codeToken.string(), &end, 0));
if (*end) {
ALOGE("%s: Expected key %s number, got '%s'.", mTokenizer->getLocation().string(),
mapUsage ? "usage" : "scan code", codeToken.string());
return BAD_VALUE;
}
KeyedVector<int32_t, Key>& map = mapUsage ? mMap->mKeysByUsageCode : mMap->mKeysByScanCode;
if (map.indexOfKey(code) >= 0) {
ALOGE("%s: Duplicate entry for key %s '%s'.", mTokenizer->getLocation().string(),
mapUsage ? "usage" : "scan code", codeToken.string());
return BAD_VALUE;
}
mTokenizer->skipDelimiters(WHITESPACE);
String8 keyCodeToken = mTokenizer->nextToken(WHITESPACE);
int32_t keyCode = getKeyCodeByLabel(keyCodeToken.string());
if (!keyCode) {
ALOGE("%s: Expected key code label, got '%s'.", mTokenizer->getLocation().string(),
keyCodeToken.string());
return BAD_VALUE;
}
uint32_t flags = 0;
for (;;) {
mTokenizer->skipDelimiters(WHITESPACE);
if (mTokenizer->isEol() || mTokenizer->peekChar() == '#') break;
String8 flagToken = mTokenizer->nextToken(WHITESPACE);
uint32_t flag = getKeyFlagByLabel(flagToken.string());
if (!flag) {
ALOGE("%s: Expected key flag label, got '%s'.", mTokenizer->getLocation().string(),
flagToken.string());
return BAD_VALUE;
}
if (flags & flag) {
ALOGE("%s: Duplicate key flag '%s'.", mTokenizer->getLocation().string(),
flagToken.string());
return BAD_VALUE;
}
flags |= flag;
}
#if DEBUG_PARSER
ALOGD("Parsed key %s: code=%d, keyCode=%d, flags=0x%08x.",
mapUsage ? "usage" : "scan code", code, keyCode, flags);
#endif
Key key;
key.keyCode = keyCode;
key.flags = flags;
map.add(code, key);
return NO_ERROR;
}
查询返回android的java键值
文件目录：android/frameworks/native/include/input/InputEventLabels.h
提供函数getKeyCodeByLabel，查询code对应的android层键值keyCode
static inline int32_t getKeyCodeByLabel(const char* label) {
return int32_t(lookupValueByLabel(label, KEYCODES));
}
其中调用lookupValueByLabel
static int lookupValueByLabel(const char* literal, const InputEventLabel *list) {
while (list->literal) {
if (strcmp(literal, list->literal) == 0) {
return list->value;
}
list++;
}
return list->value;
}
可以看出此函数是查找的过程，查找对象就是我们的键值名，如下所示：
#define DEFINE_KEYCODE(key) { #key, AKEYCODE_##key }
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),
DEFINE_KEYCODE(HOME),
DEFINE_KEYCODE(BACK),
...
DEFINE_KEYCODE(MUTE),
DEFINE_KEYCODE(PAGE_UP),
DEFINE_KEYCODE(PAGE_DOWN),
DEFINE_KEYCODE(PICTSYMBOLS),
DEFINE_KEYCODE(SWITCH_CHARSET),
...
}
......
static int lookupValueByLabel(const char* literal, const InputEventLabel *list) {
while (list->literal) {
if (strcmp(literal, list->literal) == 0) {
return list->value;
}
list++;
}
return list->value;
}