Android基于wifi的无线HID设备实现

本文地址：http://tongxinmao.com/Article/Detail/id/402

偶然间突发奇想，想到能不能让我们的在我们的手机设备上滑动触摸屏进而控制pc上的鼠标移动，也就说把我们的android设备当成是pc设备的触摸板呢？要想实现这个目标，首先要想一想android设备和pc设备之间的通讯基础是什么？这个通讯技术必须是android和pc同时支持的，目前看来也就是wifi，蓝牙。首先说一下蓝牙，蓝牙是一个提供个人局域网的安全无线电通讯技术，相对于wifi而言，蓝牙的功耗相对较低，尤其是BLE技术使得蓝牙的功耗可以和zigbee媲美了，并且android也支持了基于蓝牙的socket操作。但是pc上的java部分对于蓝牙的socket支持就不是很好了，实现起来比较麻烦。但是wifi虽然功耗相对蓝牙而言比较高了点，但是实现起来非常容易，就是socket就好了！所以在第一版本中，可以先使用wifi作为传输技术。
解决了传输技术之后，还需要解决的是都有哪些数据类型，怎么传递数据，使用什么样的协议的问题。这些问题很关键，这涉及到以后的程序可扩展性问题，如果这部分欠缺考虑的话，那么后期的修改和扩展将是一个灾难。进过仔细考量之后，决定采用google的protobuf来封装所有的数据，因为protobuf灵活，小巧，高效，正好就是我要的。
进过了几天的业余时间开发，终于出来了一个可以运行展示的初级版本，这个版本可以满足基本的需求。目前我已经将这个代码开源出来了，项目地址是github：https://github.com/CreateChance/WirelessHid

UI的设计

我要做的就是使用手机实现一个touchpad和keyboard，这就决定了UI的设计必须符合我们日常见到的实体touchpad和keyboard的样式。进过设计之后，touchpad部分设计为一个fragment，它的布局如下：

<code class="hljs xml"><linearlayout android:layout_height="match_parent" android:layout_width="match_parent" android:orientation="vertical" xmlns:android="https://schemas.android.com/apk/res/android" xmlns:tools="https://schemas.android.com/tools">

    <linearlayout android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:orientation="horizontal">

        <linearlayout android:id="@+id/speed_control" android:layout_height="match_parent" android:layout_width="65dip" android:orientation="vertical">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="1" android:textoff="@string/speed_slow" android:texton="@string/speed_slow">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="3" android:textoff="@string/speed_medium" android:texton="@string/speed_medium">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="5" android:textoff="@string/speed_fast" android:texton="@string/speed_fast">

        </togglebutton></togglebutton></togglebutton></linearlayout>

        <view android:id="@+id/touchpad" android:layout_height="match_parent" android:layout_weight="1" android:layout_width="0dp">

        <view android:background="#2b2b2b" android:id="@+id/scrollzone" android:layout_height="match_parent" android:layout_width="65dip">

        <linearlayout android:id="@+id/scroll_speed_control" android:layout_height="match_parent" android:layout_width="65dip" android:orientation="vertical">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="1" android:textoff="@string/speed_slow" android:texton="@string/speed_slow">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="3" android:textoff="@string/speed_medium" android:texton="@string/speed_medium">

            <togglebutton android:layout_height="0dp" android:layout_weight="1" android:layout_width="match_parent" android:tag="5" android:textoff="@string/speed_fast" android:texton="@string/speed_fast">

        </togglebutton></togglebutton></togglebutton></linearlayout>

    </view></view></linearlayout>

    <linearlayout android:id="@+id/buttons" android:layout_height="65dip" android:layout_width="match_parent" android:orientation="horizontal"><button android:id="@+id/left_button" android:layout_height="match_parent" android:layout_weight="1" android:layout_width="0dp" android:tag="0" android:text="left"></button><button android:layout_height="match_parent" android:layout_weight="1" android:layout_width="0dp" android:tag="1"></button></linearlayout></linearlayout></code><button android:id="@+id/right_button" android:layout_height="match_parent" android:layout_weight="1" android:layout_width="0dp" android:tag="2" android:text="right"><code class="hljs xml">

</code></button>

运行时的效果如下：
<img alt="这里写图片描述" src="https://www.2cto.com/uploadfile/Collfiles/20160614/20160614140910113.png" title="" kf="" ware="" vc="" "="" target="_blank" class="keylink" style="border-width: 0px; padding: 0px; margin: 0px auto; list-style: none; display: block; max-width: 630px; cursor: pointer; width: 630px; height: 354.375px;">vc+4tNTTwcujrNXisr+31tKyysfSu7j2ZnJhZ21lbnSjrNX7zOWyvL7WyOfPwqO6PC9wPg0KPHByZSBjbGFzcz0="brush:java;">

这个布局中首先放上3个textview在一个LinearLayout这三个textview充当真实键盘上的3个led灯：num lock, caps lock, scroll lock。然后就是一个存放实际keyboard布局的LinearLayout容器，这么做的目的是这样的：因为手机的屏幕很小，想要放下一个标准键盘上的所有的按键肯定是不行的，因此需要将键盘分区，然后分别展示，这里的这个容器就是用来存放不同分区，不同布局的键盘部分。目前我把键盘分成了2个部分：主键盘部分，导航部分加上数字部分。其中主键盘部分是我们最常使用的部分，这部分包含了26个字母，0~9数字（字母上排），12个功能键等，导航部分就是上下左右键盘，上页下页部分等，数字部分就是数字小键盘和一些控制按键，我把导航键和数字键合并在一起了，这两部分的布局如下：
主键盘部分：

<code class="hljs xml"><keyboard>

    <layout>

        <key keycode="27" keylabel="Esc">

        <key keycode="112" keylabel="F1">

        <key keycode="113" keylabel="F2">

        <key keycode="114" keylabel="F3">

        <key keycode="115" keylabel="F4">

        <key keycode="116" keylabel="F5">

        <key keycode="117" keylabel="F6">

        <key keycode="118" keylabel="F7">

        <key keycode="119" keylabel="F8">

        <key keycode="120" keylabel="F9">

        <key keycode="121" keylabel="F10">

        <key keycode="122" keylabel="F11">

        <key keycode="123" keylabel="F12">

        <key keycode="127" keylabel="Del">

    </key></key></key></key></key></key></key></key></key></key></key></key></key></key></layout>

    <layout>

        <key keycode="192" keylabel="'" shiftlabel="~">

        <key keycode="49" keylabel="1" shiftlabel="!">

        <key keycode="50" keylabel="2" shiftlabel="\@">

        <key keycode="51" keylabel="3" shiftlabel="\#">

        <key keycode="52" keylabel="4" shiftlabel="$">

        <key keycode="53" keylabel="5" shiftlabel="%">

        <key keycode="54" keylabel="6" shiftlabel="^">

        <key keycode="55" keylabel="7" shiftlabel="&">

        <key keycode="56" keylabel="8" shiftlabel="*">

        <key keycode="57" keylabel="9" shiftlabel="(">

        <key keycode="48" keylabel="0" shiftlabel=")">

        <key keycode="45" keylabel="-" shiftlabel="_">

        <key keycode="61" keylabel="=" shiftlabel="+">

        <key keycode="8" keylabel="Backspace ←" weight="1.5">

    </key></key></key></key></key></key></key></key></key></key></key></key></key></key></layout>

    <layout>

        <key keycode="9" keylabel="Tab ↹" weight="1.5">

        <key keycode="81" keylabel="Q">

        <key keycode="87" keylabel="W">

        <key keycode="69" keylabel="E">

        <key keycode="82" keylabel="R">

        <key keycode="84" keylabel="T">

        <key keycode="89" keylabel="Y">

        <key keycode="85" keylabel="U">

        <key keycode="73" keylabel="I">

        <key keycode="79" keylabel="O">

        <key keycode="80" keylabel="P">

        <key keycode="91" keylabel="[" shiftlabel="{">

        <key keycode="93" keylabel="]" shiftlabel="}">

        <key keycode="92" keylabel="\\" shiftlabel="|">

    </key></key></key></key></key></key></key></key></key></key></key></key></key></key></layout>

    <layout>

        <key keycode="20" keylabel="Caps Lock" weight="1.5">

        <key keycode="65" keylabel="A">

        <key keycode="83" keylabel="S">

        <key keycode="68" keylabel="D">

        <key keycode="70" keylabel="F">

        <key keycode="71" keylabel="G">

        <key keycode="72" keylabel="H">

        <key keycode="74" keylabel="J">

        <key keycode="75" keylabel="K">

        <key keycode="76" keylabel="L">

        <key keycode="59" keylabel=";" shiftlabel=":">

        <key keycode="44" keylabel="'" shiftlabel=""">

        <key keycode="10" keylabel="Enter ↵" weight="3.0">

    </key></key></key></key></key></key></key></key></key></key></key></key></key></layout>

    <layout>

        <key keycode="16" keyfunc="Shift" keylabel="Shift ⇧" weight="1.5">

        <key keycode="90" keylabel="Z">

        <key keycode="88" keylabel="X">

        <key keycode="67" keylabel="C">

        <key keycode="86" keylabel="V">

        <key keycode="66" keylabel="B">

        <key keycode="78" keylabel="N">

        <key keycode="77" keylabel="M">

        <key keycode="44" keylabel="," shiftlabel="<">

        <key keycode="46" keylabel="." shiftlabel=">">

        <key keycode="47" keylabel="/" shiftlabel="\?">

        <key keycode="16" keyfunc="Shift" keylabel="Shift ⇧" weight="1.5">

    </key></key></key></key></key></key></key></key></key></key></key></key></layout>

    <layout>

        <key keycode="17" keylabel="Ctrl" weight="1.5">

        <key keycode="524" keylabel="Win">

        <key keycode="18" keylabel="Alt">

        <key keycode="32" keylabel=" " weight="10.0">

        <key keycode="18" keylabel="Alt">

        <key keycode="524" keylabel="Win">

        <key keycode="93" keylabel="Menu">

        <key keycode="17" keylabel="Ctrl" weight="1.5">

    </key></key></key></key></key></key></key></key></layout>

</keyboard></code>

导航键部分：

<code class="hljs xml"><keyboard>

    <layout>

        <key keycode="154" keylabel="Print\nScreen">

        <key keycode="145" keylabel="Scroll\nLock">

        <key keycode="19" keylabel="Pause\nBreak">

    </key></key></key></layout>

    <layout>

        <key keycode="155" keylabel="Insert">

        <key keycode="36" keylabel="Home">

        <key keycode="33" keylabel="Page Up">

    </key></key></key></layout>

    <layout>

        <key keycode="127" keylabel="Delete">

        <key keycode="35" keylabel="End">

        <key keycode="34" keylabel="Page Down">

    </key></key></key></layout>

    <layout>

        <key visible="false">

        <key keycode="38" keylabel="↑">

        <key visible="false">

    </key></key></key></layout>

    <layout>

        <key keycode="37" keylabel="←">

        <key keycode="40" keylabel="↓">

        <key keycode="39" keylabel="→">

    </key></key></key></layout>

</keyboard></code>

数字键部分：

<code class="hljs xml"><keyboard>

    <layout>

        <key keycode="144" keylabel="Num\nLock">

        <key keycode="111" keylabel="/">

        <key keycode="106" keylabel="*">

        <key keycode="45" keylabel="-">

    </key></key></key></key></layout>

    <layout>

        <key keycode="0103" keylabel="7\nHome">

        <key keycode="104" keylabel="8 ↑">

        <key keycode="105" keylabel="9\nPgUp">

        <key keycode="521" keylabel="+">

    </key></key></key></key></layout>

    <layout>

        <key keycode="100" keylabel="4\n←">

        <key keycode="101" keylabel="5">

        <key keycode="102" keylabel="6\n→">

        <key visible="false">

    </key></key></key></key></layout>

    <layout>

        <key keycode="97" keylabel="1\nEnd">

        <key keycode="98" keylabel="2 ↓">

        <key keycode="99" keylabel="3\nPgDn">

        <key visible="false">

    </key></key></key></key></layout>

    <layout>

        <key keycode="96" keylabel="0\nIns" weight="2.0">

        <key keycode="110" keylabel=".\nDel">

        <key keycode="10" keylabel="Enter">

    </key></key></key></layout>

</keyboard></code>

这里的布局需要说明一下，这里我使用了layout标签表明，然后使用XmlResourceParser类来解析这个里面的内容，最后再添加到布局中去。下面贴出两张键盘的运行效果图：
主键盘：
这里写图片描述
从键盘（导航键和数字键）：

代码设计

Server端

Server整体代码就是一个app，内容不是很复杂，这里我只陈述我的代码功能和必要的代码片段，详细代码内容有限于篇幅就不贴出来了，可以查看我的github项目主页（https://github.com/CreateChance/WirelessHid）上的开源代码。
代码的基本分布如下：
这里写图片描述
各个类的作用如下：

MainActivity

这是主界面类，基本就是MouseFragment的容器，另外就是监听用户点击回退事件，如果用户在1.5s之内连续点击两次回退就退出app，基本逻辑比较简单。

WirelessHidService

这是整个app的服务，这个服务是实际将数据发送出去的地方，主要就是通过looper和handler的方式将消息队列中的数据发送出去。发送部分的逻辑：
一个looper线程

<code class="hljs java">private class DataSendThread extends Thread {

        private OutputStream os = null;

        @Override

        public void run() {

            super.run();

            Looper.prepare();

            try {

                Log.d(TAG, "I'm waiting for connecting.");

                mServerSocket = new ServerSocket(Constant.HID_TCP_PORT);

                mServerSocket.setReuseAddress(true);

                mSocket = mServerSocket.accept();

                os = mSocket.getOutputStream();

                Toast.makeText(getApplicationContext(), "Client connected!",

                        Toast.LENGTH_SHORT).show();

                Log.d(TAG, "client connected!");

            } catch (IOException e) {

                e.printStackTrace();

                return;

}

            mDataSendHandler = new Handler() {

                @Override

                public void handleMessage(Message msg) {

                    super.handleMessage(msg);

                    // send data here.

                    try {

                        ((WirelessHidProto.HidData)msg.obj).writeDelimitedTo(os);

                    } catch (IOException e) {

                        Log.d(TAG, "IOException, close all resource.");

                        mDataSendHandler = null;

                        if (mListener != null) {

                            mListener.onHandlerChanged(mDataSendHandler);

}

                        this.getLooper().quit();

                        sendBroadcast(new Intent(ACTION_RESET_CONNECTION));

                    } finally {

                        try {

                            mServerSocket.close();

                        } catch (IOException e) {

                            e.printStackTrace();

}

}

}

};

            if (mListener != null) {

                mListener.onHandlerChanged(mDataSendHandler);

}

            Looper.loop();

}

    }</code>

界面Fragment使用Handler和server交互，fragment需要实现server的DataHandlerListener接口，当Handler变化的时候通知Fragment，以便Fragment拿到最新的对象引用：
需要实现的接口

1

2

3

<code class="hljs cs">public interface DataHandlerListener {

        void onHandlerChanged(Handler handler);

}</code>

设置listener的接口：

1

2

3

<code class="hljs cs">public void setListener(DataHandlerListener listener) {

        this.mListener = listener;

}</code>

fragment也可以主动获取：

1

2

3

<code class="hljs cs">public Handler getDataSendHandler() {

    return this.mDataSendHandler;

}</code>

这里的发送使用的就是protobuf的序列化接口，关于这个接口的描述这里就不详述，可以参考google protobuf的java部分的编程指导：
https://developers.google.com/protocol-buffers/docs/javatutorial

MouseFragment

这个类是fragment类，主要是嵌套在MainActivity类中，主要逻辑功能如下：
1. 捕获用户触摸屏移动，点击事件

<code class="hljs cs">@Override

            public boolean onTouch(View v, MotionEvent event) {

                switch (event.getAction()) {

                    case MotionEvent.ACTION_DOWN:

                        //single and double click handle here.

                        mPrevX = (int) event.getX();

                        mPrevY = (int) event.getY();

                        time = new Date().getTime();

                        break;

                    case MotionEvent.ACTION_UP:

                        if (new Date().getTime() - time < mDoubleClickTimeThreshold) {

                            if ((int) event.getX() - mPrevX < mDoubleClickPosThreshold

                                    && (int) event.getY() - mPrevY < mDoubleClickPosThreshold) {

                                mouseClickPress(Constant.MOUSE_BUTTON_LEFT);

                                mouseClickRelease(Constant.MOUSE_BUTTON_LEFT);

}

}

                    case MotionEvent.ACTION_MOVE:

                        //mouse move handle here.

                        int x = (int) (event.getX() * mSpeed);

                        int y = (int) (event.getY() * mSpeed);

                        mouseMove(x - mPrevX, y - mPrevY);

                        mPrevX = x;

                        mPrevY = y;

                        break;

}

                return true;

            }</code>

1 2	`<code>2. 鼠标右击，左击事件（通过button模拟）` `</code>`

<code class="hljs cs">// setup buttons

        ViewGroup bar = (ViewGroup) view.findViewById(R.id.buttons);

        int count = bar.getChildCount();

        for (int i = 0; i < count; i++) {

            View child = bar.getChildAt(i);

            try {

                Button button = (Button) child;

                button.setOnTouchListener(new OnTouchListener() {

                    @Override

                    public boolean onTouch(View v, MotionEvent event) {

                        int which = Integer.valueOf((String) v.getTag());

                        switch (event.getAction()) {

                            case MotionEvent.ACTION_DOWN:

                                //mouse button pressed

                                //para which shows which button is pressed

                                //0 is left button

                                //1 is not used(reserved).

                                //2 is right button

                                if (which == 0) {

                                    mouseClickPress(Constant.MOUSE_BUTTON_LEFT);

                                } else if (which == 1) {

                                    //Do nothing for now.

                                } else if (which == 2) {

                                    mouseClickPress(Constant.MOUSE_BUTTON_RIGHT);

}

                                break;

                            case MotionEvent.ACTION_UP:

                                //mouse button released

                                if (which == 0) {

                                    mouseClickRelease(Constant.MOUSE_BUTTON_LEFT);

                                } else if (which == 1) {

                                    //Do nothing for now.

                                } else if (which == 2) {

                                    mouseClickRelease(Constant.MOUSE_BUTTON_RIGHT);

}

                                break;

}

                        return false;

}

});

            } catch (ClassCastException e) {

                // not a button :)

}

        }</code>

1 2	`<code>3. 鼠标滚轴滚动事件` `</code>`

<code class="hljs cs">// setup scroll

        mScrollZone = view.findViewById(R.id.scrollzone);

        mScrollZone.setOnTouchListener(new OnTouchListener() {

            private int mPrevY;

            @Override

            public boolean onTouch(View v, MotionEvent event) {

                switch (event.getAction()) {

                    case MotionEvent.ACTION_DOWN:

                        //click scroll handle here.

                        mPrevY = (int) (event.getY() * mScrollSpeed);

                        break;

                    case MotionEvent.ACTION_MOVE:

                        //mouse scroll handle here.

                        int amt = (int) (event.getY() * mScrollSpeed);

                        mouseScroll(mPrevY - amt);

                        mPrevY = amt;

                        break;

}

                return true;

}

        });</code>

1 2	`<code>4. 设置鼠标移动，滚轴滚动速度。` `</code>`

<code class="hljs java">设置移动速度

// setup speed controls

        bar = (ViewGroup) view.findViewById(R.id.speed_control);

        count = bar.getChildCount();

        for (int i = 0; i < count; i++) {

            View child = bar.getChildAt(i);

            try {

                ToggleButton button = (ToggleButton) child;

                button.setOnClickListener(new OnClickListener() {

                    @Override

                    public void onClick(View v) {

                        ToggleButton button = (ToggleButton) v;

                        // do not allow to uncheck button

                        if (!button.isChecked()) {

                            button.setChecked(true);

                            return;

}

                        updateSpeed(Integer.parseInt((String) button.getTag()));

}

});

            } catch (ClassCastException e) {

                // not a button :)

}

        }</code>

设置滚动速度

<code class="hljs java">// setup scroll speed controls

        bar = (ViewGroup) view.findViewById(R.id.scroll_speed_control);

        count = bar.getChildCount();

        for (int i = 0; i < count; i++) {

            View child = bar.getChildAt(i);

            try {

                ToggleButton button = (ToggleButton) child;

                button.setOnClickListener(new OnClickListener() {

                    @Override

                    public void onClick(View v) {

                        ToggleButton button = (ToggleButton) v;

                        // do not allow to uncheck button

                        if (!button.isChecked()) {

                            button.setChecked(true);

                            return;

}

                        updateScrollSpeed(Integer.parseInt((String) button.getTag()));

}

});

            } catch (ClassCastException e) {

                // not a button :)

}

        }</code>

更新移动速度

<code class="hljs cs">private void updateSpeed(int newSpeed) {

        // note: we assume at least button have proper speed-tag so this will

        // check what it should

        mSpeed = newSpeed;

        ViewGroup bar = (ViewGroup) getView().findViewById(R.id.speed_control);

        int count = bar.getChildCount();

        for (int i = 0; i < count; i++) {

            View child = bar.getChildAt(i);

            try {

                ToggleButton button = (ToggleButton) child;

                int speed = Integer.parseInt((String) button.getTag());

                button.setChecked(speed == newSpeed);

            } catch (ClassCastException e) {

                // not a button :)

}

}

    }</code>

更行滚动速度：

<code class="hljs cs">private void updateScrollSpeed(int newSpeed) {

        // note: we assume at least button have proper speed-tag so this will

        // check what it should

        mScrollSpeed = newSpeed;

        ViewGroup bar = (ViewGroup) getView().findViewById(R.id.scroll_speed_control);

        int count = bar.getChildCount();

        for (int i = 0; i < count; i++) {

            View child = bar.getChildAt(i);

            try {

                ToggleButton button = (ToggleButton) child;

                int speed = Integer.parseInt((String) button.getTag());

                button.setChecked(speed == newSpeed);

            } catch (ClassCastException e) {

                // not a button :)

}

}

    }</code>

KeyboardFragment

这是键盘的fragment，这其实是一个FragmentActivity，具体的键盘通过ViewGroup添加view接口addView添加相应的view：

1 2	`<code` `class="hljs avrasm">keyboard = (ViewGroup)` `this.findViewById(R.id.keyboard);` `keyboard.addView(view);</code>`

这里针对两类键盘设计了两个创建接口：
主键盘：

1

2

3

<code class="hljs cs">private View creatQwertyKeyboard(Context context) {

    return createKeyboard(context, R.xml.qwerty_keyboard);

}</code>

从键盘：

<code class="hljs avrasm">private View createNavigationAndNumericKeyboard(Context context) {

    ViewGroup view = (ViewGroup) View.inflate(context, R.layout.numeric_keyboard, null);

    ViewGroup child;

    child = (ViewGroup) view.findViewById(R.id.navigation_keyboard);

    child.addView(createKeyboard(context, R.xml.navigation_keyboard));

    child = (ViewGroup) view.findViewById(R.id.numeric_keyboard);

    child.addView(createKeyboard(context, R.xml.numeric_keyboard));

    return view;

}</code>

他们都使用了createKeyboard接口创建实际的键盘：

<code class="hljs avrasm">private Keyboard createKeyboard(Context context, int xmlResourceID) {

        final Keyboard keyboard = new Keyboard(context, xmlResourceID);

        keyboard.setKeyboardListener(new Keyboard.KeyboardListener() {

            @Override

            public void onKeyUp(int keyCode) {

                Log.d(TAG, "up keycode: " + keyCode);

                if (mDataSendHandler != null) {

                    mDataSendHandler.removeCallbacks(mLongPressCheckTask);

}

                if (mIsLongPressed) {

                    mIsLongPressed = false;

                    WirelessHidProto.HidData data = WirelessHidProto.HidData.newBuilder()

                            .setType(WirelessHidProto.HidData.DataType.KEYBOARD_LONG_RELEASE)

                            .setKeyboardValue(keyCode).build();

                    if (mDataSendHandler != null) {

                        mDataSendHandler.obtainMessage(0, data).sendToTarget();

}

                } else {

                    WirelessHidProto.HidData data = WirelessHidProto.HidData.newBuilder()

                            .setType(WirelessHidProto.HidData.DataType.KEYBOARD_HIT)

                            .setKeyboardValue(keyCode).build();

                    if (mDataSendHandler != null) {

                        mDataSendHandler.obtainMessage(0, data).sendToTarget();

}

}

}

            @Override

            public void onKeyDown(int keyCode) {

                Log.d(TAG, "key down: " + keyCode);

                if (keyCode == 144) {

                    // 144 means number lock

                    mIsNumLockActive = !mIsNumLockActive;

                    KeyboardFragment.this.findViewById(R.id.led_numlock).

                            setBackgroundColor(getResources().getColor(mIsNumLockActive ? R.color.led_on : R.color.led_off));

                } else if (keyCode == 20) {

                    // 20 means caps lock.

                    mIsCapsLockActive = !mIsCapsLockActive;

                    KeyboardFragment.this.findViewById(R.id.led_capslock).

                            setBackgroundColor(getResources().getColor(mIsCapsLockActive ? R.color.led_on : R.color.led_off));

                } else if (keyCode == 145) {

                    // 145 means scroll lock

                    mIsScrollLockActive = !mIsScrollLockActive;

                    KeyboardFragment.this.findViewById(R.id.led_scrolllock).

                            setBackgroundColor(getResources().getColor(mIsScrollLockActive ? R.color.led_on : R.color.led_off));

                } else if (mDataSendHandler != null) {

                    mLongPressCheckTask.setKeyCode(keyCode);

                    mDataSendHandler.postDelayed(mLongPressCheckTask, 1000);

}

}

});

        return keyboard;

    }</code>

这里返回一个Keyboard类对象，Keyboard类就是键盘实际的类了，这个类是LinearLayout的子类，使用XmlResourceParser来解析刚才我们定义的xml文件去获得键值和创建布局。

<code class="hljs avrasm">private LinearLayout parseKeyLayout(Context context, XmlResourceParser xmlParser)

            throws XmlPullParserException, IOException {

        LinearLayout linearLayout = new LinearLayout(context);

        linearLayout.setLayoutParams(new LayoutParams(

                xmlParser.getAttributeIntValue(null, "width", LayoutParams.MATCH_PARENT),

                xmlParser.getAttributeIntValue(null, "height", 0),

                xmlParser.getAttributeFloatValue(null, "weight", 1.0f)));

        linearLayout.setOrientation(xmlParser.getAttributeIntValue(null, "orientation",

                LinearLayout.HORIZONTAL));

        String tag;

        do {

            xmlParser.next();

            tag = xmlParser.getName();

            if (xmlParser.getEventType() == XmlResourceParser.START_TAG) {

                if (tag.equals(XML_TAG_LAYOUT)) {

                    linearLayout.addView(parseKeyLayout(context, xmlParser));

                } else if (tag.equals(XML_TAG_KEY)) {

                    Key.KeyAttributes attrs = new Key.KeyAttributes();

                    attrs.keyFunction = getStringAttributeValue(xmlParser, "keyFunc", "");

                    attrs.mainLabel = getStringAttributeValue(xmlParser, "keyLabel", "");

                    attrs.shiftLabel = getStringAttributeValue(xmlParser, "shiftLabel", "");

                    attrs.keyCode = xmlParser.getAttributeIntValue(null, "keyCode", 0);

                    Key key = new Key(context, attrs);

                    key.setLayoutParams(new LayoutParams(

                            xmlParser.getAttributeIntValue(null, "width", 0),

                            xmlParser.getAttributeIntValue(null, "height",

                                    LayoutParams.MATCH_PARENT),

                            xmlParser.getAttributeFloatValue(null, "weight", 1)));

                    key.setVisibility(xmlParser.getAttributeBooleanValue(null, "visible", true) ?

                        VISIBLE : INVISIBLE);

                    key.setKeyListener(this);

                    if (attrs.shiftLabel != null & attrs.shiftLabel.length() > 0) {

                        mKeysWithShiftLabel.add(key);

}

                    linearLayout.addView(key);

}

}

        } while (xmlParser.getEventType() != XmlResourceParser.END_TAG

                || !tag.equals(XML_TAG_LAYOUT));

        return linearLayout;

    }</code>

WirelessHid.proto

这是protobuf的数据定义文件，内容如下：

<code class="hljs ocaml">syntax = "proto2";

option java_package = "com.baniel.wirelesshid";

option java_outer_classname = "WirelessHidProto";

message HidData {

    enum DataType {

        MOUSE_MOVE = 0;

        MOUSE_CLICK_PRESS = 1;

        MOUSE_CLICK_RELEASE = 2;

        MOUSE_SCROLL = 3;

        KEYBOARD_LONG_PRESS = 4;

        KEYBOARD_LONG_RELEASE = 5;

        KEYBOARD_HIT = 6;

}

    required DataType type = 1;

    optional int32 x_shift = 2;

    optional int32 y_shift = 3;

    optional int32 mouse_key_value = 4;

    optional int32 mouse_scroll = 5;

    optional int32 keyboard_value = 6;

}</code>

这里我只定义了一个消息类型，那就是HidData这是android需要发送给pc的消息数据。这其中有消息的类型：鼠标移动，鼠标按下，鼠标释放，鼠标滚轴，键盘长按，键盘长按释放，键盘单击。x轴偏移，y轴偏移（pc系统的鼠标移动是以坐标偏移作为参数的；鼠标按键键值，鼠标滚动值，键盘按键值。关于protobuf详细的数据定义语法请见：
https://developers.google.com/protocol-buffers/docs/proto
WirelessHidProto类就是上面这个文件通过protobuf编译器编译生成的。

client端

client端的代码就比较简单了，这里我只有两个类：
这里写图片描述
具体类的说明如下：

WirelessHidClient

这个是client的主类，主要就是从socket读取来自android的数据，然后通过java Robot类移动鼠标，操作键盘输入操作：
主方法：

<code class="hljs cs">public static void main(String[] args) {

        final int HID_TCP_PORT = 34567;

        Socket mSocket = null;

        InputStream is = null;

        HidData data = null;

        try {

            mSocket = new Socket(args[0], HID_TCP_PORT);

            is = mSocket.getInputStream();

            mRobot = new Robot();

            printClientInfo(mSocket);

            while (true) {

                data = HidData.parseDelimitedFrom(is);

                if (data != null) {

                    handleData(data);

                } else {

                    break;

}

}

        } catch (UnknownHostException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

            System.exit(-1);

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

            System.exit(-1);

        } catch (AWTException e) {

            // TODO: handle exception

            System.exit(-1);

}

        System.out.println("Connection lost.");

    }</code>

具体操作：

<code class="hljs cs">//move mouse pointer to posX,posY of current position.

    private static void doMouseMove(int posX, int posY) {

        mRobot.mouseMove(mPrevX + posX, mPrevY + posY);

        mPrevX += posX;

        mPrevY += posY;

}

    //handle mouse button press.

    private static void doMousePress(int keyValue) {

        //System.out.println("mouse click value = " + keyValue);

        mRobot.mousePress(keyValue);

}

    private static void doMouseRelease(int keyValue) {

        mRobot.mouseRelease(keyValue);

}

    private static void doMouseScroll(int amt) {

        mRobot.mouseWheel(amt);

}

    private static void doKeyHit(int keyCode) {

        mRobot.keyPress(keyCode);

        mRobot.keyRelease(keyCode);

}

    private static void doKeyLongPress(int keyCode) {

        mRobot.keyPress(keyCode);

}

    private static void doKeyLongRelease(int keyCode) {

        mRobot.keyRelease(keyCode);

    }</code>

WirelessHidProto

这个类是protobuf编译器生成的，主要包含数据类的序列化操作逻辑。

好了，到这里就完全分析完了我的实现，感兴趣的朋友可以从我的github下载编译好的二进制文件，直接运行感受一下（提醒一下，客户端最好在linux上运行，windows上有点卡顿，影响体验，具体的原因以后我会找出并且解决这个问题！或者哪位大神知道可以告诉我哦～～）。下载地址：
https://github.com/CreateChance/WirelessHid/tree/master/bin
运行方式：
server端（android）：
直接安装app，然后启动即可（前提是你要链接到一个局域的wifi，并且你的pc电脑能够和android设备通讯）
client端（linux或者windows）：
命令运行：java -jar WirelessHidClient.jar 你的android设备地址