1 Input子系统作用

Android很多外设都是用到输入输出设备，比如touchscreen，键盘，音量键等，输入设备对应Android 框架是Android input子系统，像我们定制类比较多的，很多需要用到输入子系统，比如一键打开相机，一键唤醒，实体按键等。

2 Android input子系统框架

Android Input框架讲解最好的一篇文章
https://blog.csdn.net/mmmccc000/article/details/49756059
Android input框架主要分为三个部分，一个是kernel，一个是kl文件，kl也可
以划分为框架层，Framework层主要做监听、过滤、分发的工作，Android App部
分主要是接收Input子系统发上来的键值做对应的操作。

![这里写图片描述](https://img-blog.csdn.net/20180905111900628?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXFpZmEw/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70) ![这里写图片描述](https://img-blog.csdn.net/20180905164519678?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXFpZmEw/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70)

3 kernel input框架

Kernel主要是涉及Input设备节点的生成，proc文件系统的生成

有一个文章写Kernel框架非常好的，我就不再讲了，给几个链接
https://blog.csdn.net/u013604527/article/details/53432623/
https://blog.csdn.net/jscese/article/details/42123673
https://blog.csdn.net/xubin341719/article/details/7881735

4 如何在kernel添加一个新的键值

4.1 先在头文件里面添加

找个共用的头文件添加要的key值，正常是在include下面的，我的代码是在这个位
置

diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.hindex 87cf351..45a33ab 100644--- a/include/uapi/linux/input-event-codes.h+++ b/include/uapi/linux/input-event-codes.h@@ -335,7 +335,7 @@ #define KEY_RFKILL             247     /* Key that controls all radios */ #define KEY_MICMUTE            248     /* Mute / unmute the microphone */-+#define KEY_WEIQIFA_TEST 249 /* Code 255 is reserved for special needs of AT keyboard driver */

4.2 在kernel对应的位置注册和发送键值

注册的位置

    /*包含头文件*/    #include     /*声明input设备*/    struct input_dev *button_dev;    /*注册input 子设备*/    printk(KERN_ERR " xxxx_wake_init\n");    if (!(button_dev= input_allocate_device()))    {           printk(KERN_ERR "input_dev: not enough memory\n");        return -ENOMEM;    }       button_dev->name = "xxxx";    button_dev->phys = "xxxx/event0";    button_dev->id.bustype = BUS_HOST;    button_dev->id.vendor  = 0x0001;    button_dev->id.product = 0x0002;    button_dev->id.version = 0x0100;    button_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS) | BIT(EV_SYN);    set_bit(KEY_WEIQIFA_TEST,button_dev->keybit);    err = input_register_device(button_dev);    if (err) {        printk(KERN_ERR " fail to input_register_device\n");        input_free_device(button_dev);        return err;    }       printk(KERN_ERR "xxxx_wake_init success!!!\n");    return 0;

发送键值的位置

 input_report_key(button_dev, KEY_WEIQIFA_TEST, 1); input_sync(button_dev); input_report_key(button_dev, KEY_WEIQIFA_TEST, 0); input_sync(button_dev);

4.3 写一个对应这个kl文件

kl文件简单介绍

Kl文件主要是起到了承上启下的作用，kernel发过来的键值主要通过kl文件来映
射，我们来看看kl文件里面的内容把。左边的是对应kernel上报上来的键值，后
面是对应Android Framework上的键值。

 22 key 399   GRAVE 23 key 2     1 ... 49 key 103   DPAD_UP 50 key 102   HOME 51 key 105   DPAD_LEFT 52 key 106   DPAD_RIGHT 53 key 115   VOLUME_UP

kl文件哪里来的呢

我们看项目配置下面，有很多kl文件，那么是每个input子系统对应一个kl文件，
还是所有的项目共用一个kl文件？
kl源码位置在

./frameworks/base/data/keyboards/AVRCP.kl./frameworks/base/data/keyboards/G./frameworks/base/data/keyboards/Vendor_0079_Product_0011.kl./frameworks/base/data/keyboards/Vendor_045e_Product_028e.kl...

在运行的设备里，它的位置如下

rk3399_mid:/ # busybox find / -iname *.kl/system/usr/keylayout/Generic.kl/system/usr/keylayout/Vendor_0079_Product_0011.kl/system/usr/keylayout/qwerty.kl/system/usr/keylayout/rk29-keypad.kl/system/usr/keylayout/rtkbt_virtual_hid.kl...rk3399_mid:/ #

kl是跟input设备如何对应起来的呢

我们可以用这个命令来看看 cat /proc/bus/input/devices
kl文件里面的vendor和product分别对应下面的vendor和product

rk3399_mid:/ # cat /proc/bus/input/devicesI: Bus=0019 Vendor=0001 Product=0002 Version=0100N: Name="xxxx"P: Phys=iflytek/event0S: Sysfs=/devices/virtual/input/input0U: Uniq=H: Handlers=event0 cpufreqB: PROP=0B: EV=bB: KEY=100000 0 0 0B: ABS=0

添加我们对应的kl文件
文件命名跟你申请的vendor和product对应上面的input设备对应的kl文件应该是：Vendor_0001_Product_0002.kl
里面的内容如下，当然如果你没有配置kl文件，默认会去Generic.kl找键值映
射，如果里面也没有，就会去其他kl文件继续找。

# OnLive, Inc. OnLive Wireless Controllerkey 249 BUTTON_A

4.4 mtk平台的一个input 子系统驱动例子

上面写的是在rockchip平台做的例子，下面给出一个mtk平台的例子
[mkt平台的input子系统例子]
(https://blog.csdn.net/weiqifa0/article/details/50387504)

5 Framework input系统介绍

Framework 主要做的事情是监听底层的input，然后分发给上层
下面的这个说的框架非常好，可以看看，我介绍完主要说明如何添加一个新的key
到系统里面
https://blog.csdn.net/wangkaiblog/article/details/12085183
https://blog.csdn.net/mmmccc000/article/details/49756059

6 添加一个新的键值

主要涉及到几个文件位置
下面列出需要修改的文件还有修改的差异点
base/api/current.txt
base/api/system-current.txt
base/core/java/android/view/KeyEvent.java
base/core/res/res/values/attrs.xml
/Generic.kl这里也可以根据驱动添加/
base/data/keyboards/Generic.kl
base/policy/src/com/android/internal/policy/impl/PhoneFallbackEventHandler.java
native/include/android/keycodes.h
native/include/input/InputEventLabels.h

diff --git a/api/current.txt b/api/current.txtindex 63fa997..a7a4a2b 100644--- a/api/current.txt+++ b/api/current.txt@@ -41599,6 +41599,7 @@ package android.view {     field public static final int KEYCODE_ASSIST = 219; // 0xdb     field public static final int KEYCODE_AT = 77; // 0x4d     field public static final int KEYCODE_AUDIO = 314; // 0x13a+    field public static final int KEYCODE_WEIQIFA = 315; // 0x13B     field public static final int KEYCODE_AVR_INPUT = 182; // 0xb6     field public static final int KEYCODE_AVR_POWER = 181; // 0xb5     field public static final int KEYCODE_B = 30; // 0x1ediff --git a/api/system-current.txt b/api/system-current.txtindex 19135aa..956ea3e 100644--- a/api/system-current.txt+++ b/api/system-current.txt@@ -44781,6 +44781,7 @@ package android.view {     field public static final int KEYCODE_ASSIST = 219; // 0xdb     field public static final int KEYCODE_AT = 77; // 0x4d     field public static final int KEYCODE_AUDIO = 314; // 0x13a+    field public static final int KEYCODE_WEIQIFA = 315; // 0x13b     field public static final int KEYCODE_AVR_INPUT = 182; // 0xb6     field public static final int KEYCODE_AVR_POWER = 181; // 0xb5     field public static final int KEYCODE_B = 30; // 0x1ediff --git a/core/java/android/view/KeyEvent.java b/core/java/android/view/KeyEvent.javaindex 056f2c9..f2d5235 100755--- a/core/java/android/view/KeyEvent.java+++ b/core/java/android/view/KeyEvent.java@@ -832,6 +832,7 @@ public class KeyEvent extends InputEvent implements Parcelable {     public static final int KEYCODE_TV_MEDIA_PAUSE = 304;     public static final int KEYCODE_WLAN           = 313;     public static final int KEYCODE_AUDIO          = 314;+    public static final int KEYCODE_WEIQIFA          = 315; //$_rbox_$_modify_$ end     private static final int LAST_KEYCODE = KEYCODE_TV_MEDIA_PAUSE;diff --git a/core/java/com/android/internal/policy/PhoneFallbackEventHandler.java b/core/java/com/android/internal/policy/PhoneFallbackEventHandler.javaindex e6635a1..366790c 100755--- a/core/java/com/android/internal/policy/PhoneFallbackEventHandler.java+++ b/core/java/com/android/internal/policy/PhoneFallbackEventHandler.java@@ -141,7 +141,12 @@ public class PhoneFallbackEventHandler implements FallbackEventHandler {             }             case KeyEvent.KEYCODE_AUDIO: {                 Log.i(TAG, "---KEYCODE_AUDIO DOWN---");+                    }+            case KeyEvent.KEYCODE_WEIQIFA: {+                Log.i(TAG,"KEYCODE_WEIQIFA");+            }+                        case KeyEvent.KEYCODE_CAMERA: {                                if (getKeyguardManager().inKeyguardRestrictedInputMode() || dispatcher == null) {diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xmlindex 93743df..094e6c2 100755--- a/core/res/res/values/attrs.xml+++ b/core/res/res/values/attrs.xml@@ -1861,6 +1861,7 @@ i         <enum name="KEYCODE_MICMUTE" value="312" />         <enum name="KEYCODE_WLAN" value="313" />         <enum name="KEYCODE_AUDIO" value="314" />+        <enum name="KEYCODE_WEIQIFA" value="315" />          diff --git a/include/android/keycodes.h b/include/android/keycodes.hindex e3586b2..b657424 100755--- a/include/android/keycodes.h+++ b/include/android/keycodes.h@@ -777,6 +777,7 @@ enum {     AKEYCODE_MICMUTE            = 312,     AKEYCODE_WLAN               = 313,     AKEYCODE_AUDIO              = 314+    AKEYCODE_WEIQIFA              = 315     // 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.diff --git a/include/input/InputEventLabels.h b/include/input/InputEventLabels.hindex fabf912..1cd69a2 100755--- a/include/input/InputEventLabels.h+++ b/include/input/InputEventLabels.h@@ -68,6 +68,7 @@ static const InputEventLabel KEYCODES[] = {     DEFINE_KEYCODE(POWER),     DEFINE_KEYCODE(WLAN),     DEFINE_KEYCODE(AUDIO),+    DEFINE_KEYCODE(WEIQIFA),     DEFINE_KEYCODE(CAMERA),     DEFINE_KEYCODE(CLEAR),     DEFINE_KEYCODE(A),

如果出现以下编译错误

out/target/common/obj/PACKAGING/test-api.txt:41961: error 5: Added public field android.view.KeyEvent.KEYCODE_WEIQIFA******************************You have tried to change the API from what has been previously approved.To make these errors go away, you have two choices:   1) You can add "@hide" javadoc comments to the methods, etc. listed in the      errors above.   2) You can update current.txt by executing the following command:      make update-api      To submit the revised current.txt to the main Android repository,      you will need approval.******************************

提示你运行make update-api，但是要先回退current.txt 和system-current.txt，因为这两个文件就是make update-api生成出来的

git checkout api/current.txt git checkout api/system-current.txtmake update-api

关于make update-api详细看这个https://blog.csdn.net/u010229714/article/details/73840014

如果需要调试，可以打开下面的调试文件

--- a/services/core/java/com/android/server/input/InputManagerService.java+++ b/services/core/java/com/android/server/input/InputManagerService.java@@ -125,7 +125,7 @@ import libcore.util.Objects; public class InputManagerService extends IInputManager.Stub         implements Watchdog.Monitor {     static final String TAG = "InputManager";-    static final boolean DEBUG = false;+    static final boolean DEBUG = true;     private static final String EXCLUDED_DEVICES_PATH = "etc/excluded-input-devices.xml";--- a/services/core/java/com/android/server/policy/PhoneWindowManager.java+++ b/services/core/java/com/android/server/policy/PhoneWindowManager.java@@ -172,7 +172,7 @@ public class PhoneWindowManager implements WindowManagerPolicy {     static final String TAG = "WindowManager";     static final boolean DEBUG = false;     static final boolean localLOGV = false;-    static final boolean DEBUG_INPUT = false;+    static final boolean DEBUG_INPUT = true;     static final boolean DEBUG_KEYGUARD = false;     static final boolean DEBUG_LAYOUT = false;     static final boolean DEBUG_STARTING_WINDOW = false;--- a/services/inputflinger/InputDispatcher.cpp+++ b/services/inputflinger/InputDispatcher.cpp@@ -17,31 +17,31 @@ #define LOG_TAG "InputDispatcher" #define ATRACE_TAG ATRACE_TAG_INPUT-//#define LOG_NDEBUG 0+#define LOG_NDEBUG 1 // Log detailed debug messages about each inbound event notification to the dispatcher.-#define DEBUG_INBOUND_EVENT_DETAILS 0+#define DEBUG_INBOUND_EVENT_DETAILS 1 // Log detailed debug messages about each outbound event processed by the dispatcher.-#define DEBUG_OUTBOUND_EVENT_DETAILS 0+#define DEBUG_OUTBOUND_EVENT_DETAILS 1 // Log debug messages about the dispatch cycle.-#define DEBUG_DISPATCH_CYCLE 0+#define DEBUG_DISPATCH_CYCLE 1 // Log debug messages about registrations.-#define DEBUG_REGISTRATION 0+#define DEBUG_REGISTRATION 1 // Log debug messages about input event injection.-#define DEBUG_INJECTION 0+#define DEBUG_INJECTION 1 // Log debug messages about input focus tracking.-#define DEBUG_FOCUS 0+#define DEBUG_FOCUS 1 // Log debug messages about the app switch latency optimization.-#define DEBUG_APP_SWITCH 0+#define DEBUG_APP_SWITCH 1 // Log debug messages about hover events.-#define DEBUG_HOVER 0+#define DEBUG_HOVER 1 #include "InputDispatcher.h"diff --git a/services/inputflinger/InputReader.cpp b/services/inputflinger/InputReader.cppindex c8dc454..3a622fc 100644--- a/services/inputflinger/InputReader.cpp+++ b/services/inputflinger/InputReader.cpp@@ -16,10 +16,10 @@ #define LOG_TAG "InputReader"-//#define LOG_NDEBUG 0+#define LOG_NDEBUG 1 // Log debug messages for each raw event received from the EventHub.-#define DEBUG_RAW_EVENTS 0+#define DEBUG_RAW_EVENTS 1 // Log debug messages about touch screen filtering hacks. #define DEBUG_HACKS 0diff --git a/libs/input/InputTransport.cpp b/libs/input/InputTransport.cppindex 2dff4e0..977aa22 100644--- a/libs/input/InputTransport.cpp+++ b/libs/input/InputTransport.cpp@@ -5,19 +5,19 @@ // #define LOG_TAG "InputTransport"-//#define LOG_NDEBUG 0+#define LOG_NDEBUG 1 // Log debug messages about channel messages (send message, receive message)-#define DEBUG_CHANNEL_MESSAGES 0+#define DEBUG_CHANNEL_MESSAGES 1 // Log debug messages whenever InputChannel objects are created/destroyed-#define DEBUG_CHANNEL_LIFECYCLE 0+#define DEBUG_CHANNEL_LIFECYCLE 1 // Log debug messages about transport actions-#define DEBUG_TRANSPORT_ACTIONS 0+#define DEBUG_TRANSPORT_ACTIONS 1 // Log debug messages about touch event resampling-#define DEBUG_RESAMPLING 0+#define DEBUG_RESAMPLING 1

7 App接收键值

主要参照这个链接来写
https://www.cnblogs.com/zhujiabin/p/5915802.html
例程Android studio源码
链接：https://pan.baidu.com/s/1hzhQ-dLSRnAbg2Q8w5qKPw 密码：944g

@Override    public boolean dispatchKeyEvent(KeyEvent event) {        if(event.getKeyCode() == KeyEvent.KEYCODE_ENTER){            /*隐藏软键盘*/            InputMethodManager inputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);            if(inputMethodManager.isActive()){                inputMethodManager.hideSoftInputFromWindow(MainActivity.this.getCurrentFocus().getWindowToken(), 0);            }            edittext.setText("success");            webview.loadUrl(URL);            return true;        }        return super.dispatchKeyEvent(event);    }

8 命令调试

8.1 测试上报时间

触发Input上报的时间点

rk3399_mid:/ $ logcat -s "CAE_LOG"|grep -E CAEIvwCb09-06 14:10:13.502   327   436 D CAE_LOG : CAEIvwCb angle = 23 ,beam = 0 CMScore = 1643

APK接收到键值的时间点

09-06 14:10:13.518 5693-5693/com.hu.audiotest D/audiotest_MainActivity: KeyEvent.KEYCODE_ENTER KeyCode009-06 14:10:13.522 5693-5693/com.hu.audiotest D/audiotest_MainActivity: KeyEvent.KEYCODE_ENTER KeyCode0

消耗的时间大概需要16MS，但是触发是通过HAL层触发的，如果从Kerne触发事间会更短一些

8.2 设备文件调试

我们kernel下面正常用 getevent 来调试
getevent -l
cat /proc/bus/input/devices

rk3399_mid:/ # getevent -ladd device 1: /dev/input/event2  name:     "rk29-keypad"add device 2: /dev/input/event1  name:     "as9102 Touchscreen"add device 3: /dev/input/event0  name:     "iflytek"/dev/input/event0: EV_KEY       00f9                 DOWN/dev/input/event0: EV_SYN       SYN_REPORT           00000000/dev/input/event0: EV_KEY       00f9                 UP/dev/input/event0: EV_SYN       SYN_REPORT           00000000

8.3 adb 上报键值调试

我们正常用adb shell input keyevent xx xx代表键值
可以用input来触发touchscreen也是可以的
有个比较好的文章
https://blog.csdn.net/jlminghui/article/details/39268419
大部分支持的键值如下

0 -->  "KEYCODE_UNKNOWN"1 -->  "KEYCODE_MENU"2 -->  "KEYCODE_SOFT_RIGHT"3 -->  "KEYCODE_HOME"4 -->  "KEYCODE_BACK"5 -->  "KEYCODE_CALL"6 -->  "KEYCODE_ENDCALL"7 -->  "KEYCODE_0"8 -->  "KEYCODE_1"9 -->  "KEYCODE_2"10 -->  "KEYCODE_3"11 -->  "KEYCODE_4"12 -->  "KEYCODE_5"13 -->  "KEYCODE_6"14 -->  "KEYCODE_7"15 -->  "KEYCODE_8"16 -->  "KEYCODE_9"17 -->  "KEYCODE_STAR"18 -->  "KEYCODE_POUND"19 -->  "KEYCODE_DPAD_UP"20 -->  "KEYCODE_DPAD_DOWN"21 -->  "KEYCODE_DPAD_LEFT"22 -->  "KEYCODE_DPAD_RIGHT"23 -->  "KEYCODE_DPAD_CENTER"24 -->  "KEYCODE_VOLUME_UP"25 -->  "KEYCODE_VOLUME_DOWN"26 -->  "KEYCODE_POWER"27 -->  "KEYCODE_CAMERA"28 -->  "KEYCODE_CLEAR"29 -->  "KEYCODE_A"30 -->  "KEYCODE_B"31 -->  "KEYCODE_C"32 -->  "KEYCODE_D"33 -->  "KEYCODE_E"34 -->  "KEYCODE_F"35 -->  "KEYCODE_G"36 -->  "KEYCODE_H"37 -->  "KEYCODE_I"38 -->  "KEYCODE_J"39 -->  "KEYCODE_K"40 -->  "KEYCODE_L"41 -->  "KEYCODE_M"42 -->  "KEYCODE_N"43 -->  "KEYCODE_O"44 -->  "KEYCODE_P"45 -->  "KEYCODE_Q"46 -->  "KEYCODE_R"47 -->  "KEYCODE_S"48 -->  "KEYCODE_T"49 -->  "KEYCODE_U"50 -->  "KEYCODE_V"51 -->  "KEYCODE_W"52 -->  "KEYCODE_X"53 -->  "KEYCODE_Y"54 -->  "KEYCODE_Z"55 -->  "KEYCODE_COMMA"56 -->  "KEYCODE_PERIOD"57 -->  "KEYCODE_ALT_LEFT"58 -->  "KEYCODE_ALT_RIGHT"59 -->  "KEYCODE_SHIFT_LEFT"60 -->  "KEYCODE_SHIFT_RIGHT"61 -->  "KEYCODE_TAB"62 -->  "KEYCODE_SPACE"63 -->  "KEYCODE_SYM"64 -->  "KEYCODE_EXPLORER"65 -->  "KEYCODE_ENVELOPE"66 -->  "KEYCODE_ENTER"67 -->  "KEYCODE_DEL"68 -->  "KEYCODE_GRAVE"69 -->  "KEYCODE_MINUS"70 -->  "KEYCODE_EQUALS"71 -->  "KEYCODE_LEFT_BRACKET"72 -->  "KEYCODE_RIGHT_BRACKET"73 -->  "KEYCODE_BACKSLASH"74 -->  "KEYCODE_SEMICOLON"75 -->  "KEYCODE_APOSTROPHE"76 -->  "KEYCODE_SLASH"77 -->  "KEYCODE_AT"78 -->  "KEYCODE_NUM"79 -->  "KEYCODE_HEADSETHOOK"80 -->  "KEYCODE_FOCUS"81 -->  "KEYCODE_PLUS"82 -->  "KEYCODE_MENU"83 -->  "KEYCODE_NOTIFICATION"84 -->  "KEYCODE_SEARCH"85 -->  "TAG_LAST_KEYCODE"

Android(安卓)Input子系统-含实例源码