Android getevent拦截输入事件

上篇文章《Android AccessibilityService拦截事件及VR眼镜返回按键捕捉》我们介绍了如何用AccessibilityService来拦截事件。

本篇我们来介绍另一种拦截按键的方式，就是在shell的状态下，使用getevent命令对输入事件进行分析。必须要说明的是getevent命令使用场景有：

1.在PC端shell环境下，不必root

2.在APP端使用必须要root权限

package com.jason.btnmonitor;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initMonitor();        Button get = (Button) findViewById(R.id.get);        Button start = (Button) findViewById(R.id.start);        Button stop = (Button) findViewById(R.id.stop);        get.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                getDevices();            }        });        start.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                startMonitor();            }        });        stop.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                stopMonitor();            }        });    }    private void getDevices(){        BtnMonitorController.getInstance().getVRDevice();    }    private void initMonitor(){        BtnMonitorController.getInstance().init();    }    public void startMonitor(){        BtnMonitorController.getInstance().start();    }    public void stopMonitor(){        BtnMonitorController.getInstance().stop();    }    private void releaseMonitor(){        BtnMonitorController.getInstance().release();    }    @Override    protected void onDestroy() {        super.onDestroy();        releaseMonitor();    }}

MainActivity的实现。

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context="com.jason.btnmonitor.MainActivity">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="get"        android:id="@+id/get"        />    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="start"        android:id="@+id/start"        android:layout_toRightOf="@+id/get"        />    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="stop"        android:layout_toRightOf="@+id/start"        android:id="@+id/stop"        /></RelativeLayout>

layout的实现。

package com.jason.btnmonitor;import android.os.Handler;import android.os.Message;import android.util.Log;import com.stericson.RootTools.RootTools;import com.stericson.RootTools.exceptions.RootDeniedException;import com.stericson.RootTools.execution.Command;import com.stericson.RootTools.execution.Shell;import java.io.IOException;import java.util.concurrent.TimeoutException;public class BtnMonitorController {    private static final String COMMAND_GET_DEVICE_VR = "getevent";    private static final String COMMAND_GET_VR_EVENT = "getevent -l -t ";    public static final int MSG_EVENT_INPUT = 9000;    private String deviceName="/dev/input/event19"; //demo监听的是event19，这里可以改为你所要监听的event    private static boolean isMonitorStart = false;    private static boolean hasVR = false;    private Shell shell;    private Command command;    private Handler handler;    private static BtnMonitorController instance ;        private BtnMonitorController(){            }        public static BtnMonitorController getInstance(){        if (instance == null) {            synchronized (BtnMonitorController.class){                if (instance == null) {                    instance = new BtnMonitorController() ;                }            }        }        return instance ;    }    public void init(){        try {            shell = RootTools.getShell(true);//getevent命令必须要root        } catch (IOException e) {            e.printStackTrace();            LogUtil.e("shell init error");        } catch (TimeoutException e) {            e.printStackTrace();            LogUtil.e("shell init error");        } catch (RootDeniedException e) {            e.printStackTrace();            LogUtil.e("shell init error");        }        handler = new Handler() {            public void handleMessage(Message msg) {                switch (msg.what) {                    case MSG_EVENT_INPUT:                        LogUtil.i(""+msg.obj);                        break;                }                super.handleMessage(msg);            }        };    }//getVRDevice会输出你的inputdevice的列表，选中你想要监听的设备，替换deviceName    public void getVRDevice(){        LogUtil.i("BtnMonitor getVRDevice" );        if(isMonitorStart){            LogUtil.e("BtnMonitor is started already!");            return;        }        startCMD(COMMAND_GET_DEVICE_VR);    }    public void start(){        LogUtil.i("BtnMonitor start" );        if(isMonitorStart){            LogUtil.e("BtnMonitor is started already!");            return;        }        startCMD(COMMAND_GET_VR_EVENT+deviceName);    }    public void stop(){        LogUtil.i("BtnMonitor stop" );        if(command.isFinished()){            LogUtil.e("BtnMonitor is stopped already!");            return;        }        command.terminate("stop");    }    public void release(){        LogUtil.i("BtnMonitor release" );        if(handler != null && handler.hasMessages(MSG_EVENT_INPUT)){            handler.removeMessages(MSG_EVENT_INPUT);            handler = null;        }        if(isMonitorStart){            command.terminate("exit");            isMonitorStart = false;        }        try {            if(shell != null)            shell.close();        } catch (IOException e) {            e.printStackTrace();            LogUtil.e("shell close IOException");        }    }    private void startCMD(String cmd){        isMonitorStart = true;        command = new Command(0, 0, cmd) {            @Override            public void output(int id, String line) {                LogUtil.e("MainActivity.java:output, id:" + id + ", output:" + line);                Message m = new Message();                m.what = MSG_EVENT_INPUT;                m.obj = line + "\n";                handler.sendMessage(m);            }            @Override            public void commandCompleted(int arg0, int arg1) {                // TODO Auto-generated method stub                LogUtil.e("MainActivity.java:commandCompleted, arg0:" + arg0 + ", arg1:" + arg1);                Message m = new Message();                m.what = MSG_EVENT_INPUT;                m.obj = "commandCompleted\n" + "================================\n";                handler.sendMessage(m);                isMonitorStart = false;            }            @Override            public void commandOutput(int arg0, String arg1) {                // TODO Auto-generated method stub                LogUtil.e( "MainActivity.java:commandOutput, arg0:" + arg0 + ", arg1:" + arg1);                Message m = new Message();                m.what = MSG_EVENT_INPUT;                m.obj = "commandOutput, arg0:" + arg0 + ", arg1:" + arg1 + "\n";                handler.sendMessage(m);            }            @Override            public void commandTerminated(int arg0, String arg1) {                // TODO Auto-generated method stub                LogUtil.e("MainActivity.java:commandTerminated, arg0:" + arg0 + ", arg1:" + arg1);                Message m = new Message();                m.what = MSG_EVENT_INPUT;                m.obj = "commandTerminated, reason:" + arg1 + "\n" + "================================\n";                handler.sendMessage(m);                isMonitorStart = false;            }        };        try {            shell.add(command);        } catch (IOException e) {            e.printStackTrace();        }    }}

BtnMonitorController的实现，使用的是开源项目的RootTools。github工程地址

https://github.com/graygray/getevent.git

 $ getevent /dev/input/event19                             0004 0004 000900020001 0111 000000010000 0000 000000000004 0004 000900020001 0111 000000000000 0000 00000000

监听到的VR设备（默认类型为鼠标）单击返回键的内容

$ getevent -l -t /dev/input/event19                       [   17437.061273] EV_MSC       MSC_SCAN             00090002            [   17437.061273] EV_KEY       BTN_RIGHT            DOWN                [   17437.061273] EV_SYN       SYN_REPORT           00000000            [   17437.156346] EV_MSC       MSC_SCAN             00090002            [   17437.156346] EV_KEY       BTN_RIGHT            UP                  [   17437.156346] EV_SYN       SYN_REPORT           00000000            [   17444.748923] EV_MSC       MSC_SCAN             00090002            [   17444.748923] EV_KEY       BTN_RIGHT            DOWN                [   17444.748923] EV_SYN       SYN_REPORT           00000000            [   17446.244327] EV_MSC       MSC_SCAN             00090002            [   17446.244327] EV_KEY       BTN_RIGHT            UP                  [   17446.244327] EV_SYN       SYN_REPORT           00000000  

监听到的VR设备（默认类型为鼠标）返回键长按的内容，-t加上了时间戳用于判断是否是长按

针对收到的message内容可以判断BACK键的单击和长按。