android关闭手机偷录她人功能实现（退出程序依然录像）

最近的几个项目中，遇到了这个需求。正常情况下，我们使用相机录像的话，都是打开系统照相机进行操作；再或者就是使用SurfaceView进行绘制。
但是这样的话android就需要在页面上一直保持一个SurfaceView进行操作，那么怎么当程序进入后台时就没法操作了呀！怎么办呢？

项目中需求效果如下：

当然如果要录像那么SurfaceView是少不了的！那么就应该想到WindowManager来绘制桌面小控件的原理了！那么就可以保证这个SurfaceView一直存在了！再把宽高设置为1dp，就可以让用户视觉上有了后台录制的效果了！

一、首先我们需要一个SurfaceView：

<?xml version="1.0" encoding="utf-8"?><LinearLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/small_window_layout"    android:layout_width="1dip"    android:layout_height="1dip"    android:background="@drawable/bg_small"    >    <SurfaceView        android:id="@+id/percent"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:gravity="center"        android:textColor="#ffffff"        /></LinearLayout>

二、然后进行的操作就是生产这个小控件了：

   public FloatWindowSmallView(Context context) {        super(context);        windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);        LayoutInflater.from(context).inflate(R.layout.float_window_small, this);        View view = findViewById(R.id.small_window_layout);        viewWidth = view.getLayoutParams().width;        viewHeight = view.getLayoutParams().height;//        SurfaceView percentView = (SurfaceView) findViewById(R.id.percent);//        percentView.setText(MyWindowManager.getUsedPercentValue(context));    }    /**     * 将小悬浮窗的参数传入，用于更新小悬浮窗的位置。     *     * @param params 小悬浮窗的参数     */    public void setParams(WindowManager.LayoutParams params) {        mParams = params;    }

三、那桌面控件有了，下面当然就是使用WindowManager添加到桌面上了：

/**     * 创建一个小悬浮窗。初始位置为屏幕的右部中间位置。     *     * @param context 必须为应用程序的Context.     */    public void createSmallWindow(Context context) {        mContext = context;        WindowManager windowManager = getWindowManager(context);        int screenWidth = windowManager.getDefaultDisplay().getWidth();        int screenHeight = windowManager.getDefaultDisplay().getHeight();        if (smallWindow == null) {            smallWindow = new FloatWindowSmallView(context);            if (smallWindowParams == null) {                smallWindowParams = new LayoutParams();                smallWindowParams.type = LayoutParams.TYPE_PHONE;                smallWindowParams.format = PixelFormat.RGBA_8888;                smallWindowParams.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL                        | LayoutParams.FLAG_NOT_FOCUSABLE;                smallWindowParams.gravity = Gravity.LEFT | Gravity.TOP;                smallWindowParams.width = FloatWindowSmallView.viewWidth;                smallWindowParams.height = FloatWindowSmallView.viewHeight;                smallWindowParams.x = screenWidth;                smallWindowParams.y = screenHeight / 2;            }            smallWindow.setParams(smallWindowParams);            windowManager.addView(smallWindow, smallWindowParams);            mSurfaceview = (SurfaceView) smallWindow.findViewById(R.id.percent);            SurfaceHolder holder = mSurfaceview.getHolder();            holder.addCallback(this);            // setType必须设置，要不出错.            holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);        }    }

四、这个时候我们需要的SurfaceView就有了，那么，怎么在后台进行操作呢？自然而然就想到了Service了

在Service中执行桌面控件的操作：

 @Override    public int onStartCommand(Intent intent, int flags, int startId) {        myWindowManager = new MyWindowManager();        createWindow();        return super.onStartCommand(intent, flags, startId);    }    private void createWindow() {        // 当前界面是桌面，且没有悬浮窗显示，则创建悬浮窗。        myWindowManager.removeSmallWindow(getApplicationContext());        myWindowManager.createSmallWindow(getApplicationContext());    }

五、在activity中对Service绑定，进行录像的操作

  conn = new MyServiceConn();  bindService(intent, conn, BIND_AUTO_CREATE);private class MyServiceConn implements ServiceConnection {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            // TODO Auto-generated method stub            binder = (FloatWindowService.myServiceBinder) service;            if (isVedio) {                binder.startRecord();            } else {                binder.stopRecord();            }        }        @Override        public void onServiceDisconnected(ComponentName name) {            // TODO Auto-generated method stub        }    }

六、在Service中控制myWindowManager中的录像的开始和结束

public class myServiceBinder extends Binder {        public void startRecord() {            myWindowManager.startVideo();        }        public void stopRecord() {            myWindowManager.stopVideo();        }    }

七、最后在myWindowManager进行录像操作就OK了。

 public void startVideo() {        if (mRecorder == null) {            mRecorder = new MediaRecorder();        }        camera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);        if (camera != null) {            camera.setDisplayOrientation(270);            camera.unlock();            mRecorder.setCamera(camera);        }        try {            // 这两项需要放在setOutputFormat之前            mRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);            mRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);            // Set output file format            mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);            // 这两项需要放在setOutputFormat之后            mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);            mRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);            mRecorder.setVideoSize(640, 480);//                        mRecorder.setVideoSize(width, height);            mRecorder.setVideoFrameRate(30);            mRecorder.setVideoEncodingBitRate(3 * 1024 * 1024);            mRecorder.setOrientationHint(90);            //设置记录会话的最大持续时间（毫秒）            mRecorder.setMaxDuration(7200 * 1000);//                        mRecorder.setMaxDuration(Integer.MAX_VALUE);            mRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());            path = Environment.getExternalStorageDirectory().getAbsolutePath();            if (path != null) {                File dir = new File(path + "/DCIM/Camera");                if (!dir.exists()) {                    dir.mkdir();                }                videoTitle = System.currentTimeMillis() + ".mp4";                path = dir + "/" + videoTitle;                mRecorder.setOutputFile(path);                mRecorder.prepare();                mRecorder.start();//                            mBtnStartStop.setText("录制结束");                Log.i("LogUtils", "path=====>" + path);            } else {                Toast.makeText(mContext, "SD卡不存在...", Toast.LENGTH_LONG).show();            }        } catch (Exception e) {            e.printStackTrace();        }    }    public void stopVideo() {        try {            mRecorder.stop();            mRecorder.reset();            mRecorder.release();            mRecorder = null;//                            mBtnStartStop.setText("开始录制视频");            if (camera != null) {                camera.release();                camera = null;            }        } catch (Exception e) {            e.printStackTrace();        }    }    @Override    public void surfaceCreated(SurfaceHolder surfaceHolder) {        mSurfaceHolder = surfaceHolder;    }    @Override    public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) {// 将holder，这个holder为开始在onCreate里面取得的holder，将它赋给mSurfaceHolder        mSurfaceHolder = surfaceHolder;    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        mSurfaceview = null;        mSurfaceHolder = null;        if (mRecorder != null) {            mRecorder.release();            mRecorder = null;            Log.i("LogUtils", "surfaceDestroyed release mRecorder");        }        if (camera != null) {            camera.release();            camera = null;        }    }

记得配置权限等

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.ddv.www.candidcamerademo">    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />    <uses-permission android:name="android.permission.GET_TASKS" />    <uses-feature android:name="android.hardware.camera" />    <uses-feature android:name="android.hardware.camera.autofocus" />    <uses-permission android:name="android.permission.CAMERA"></uses-permission>    <uses-permission android:name="android.permission.RECORD_AUDIO"></uses-permission>    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <service android:name=".FloatWindowService" />    </application></manifest>

demo下载地址：http://download.csdn.net/detail/huangxiaoguo1/9711893

有什么不足，望大家指教，谢谢….