屏幕录制5.0开始支持

Android从4.0开始提供手机录制方法，但是需要root权限。5.0开始，提供不需要root的app录制方法，只需要用户授权。
清单文件中声明的权限：

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

在6.0以上需要动态权限获取

public static void checkPermission(AppCompatActivity activity) {
        if (Build.VERSION.SDK_INT >= 23) {
            int checkPermission =
                    ContextCompat.checkSelfPermission(activity, Manifest.permission.RECORD_AUDIO)
                            + ContextCompat.checkSelfPermission(activity, Manifest.permission.READ_PHONE_STATE)
                            + ContextCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE)
                            + ContextCompat.checkSelfPermission(activity, Manifest.permission.READ_EXTERNAL_STORAGE);
            if (checkPermission != PackageManager.PERMISSION_GRANTED) {
                //动态申请
                ActivityCompat.requestPermissions(activity, new String[]{
                        Manifest.permission.RECORD_AUDIO,
                        Manifest.permission.READ_PHONE_STATE,
                        Manifest.permission.READ_EXTERNAL_STORAGE,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE}, 123);
                return;
            } else {
                return;
            }
        }
        return;
    }

获取用户录制屏幕授权
MediaProjectionManager系统提供的一种服务，Intent启动弹窗Activity，极少机型没有对应授权Activity，需要处理：

MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) activity.
                            getSystemService(Context.MEDIA_PROJECTION_SERVICE);
                    if (mediaProjectionManager != null){
                        Intent intent = mediaProjectionManager.createScreenCaptureIntent();
                        PackageManager packageManager = activity.getPackageManager();
                        if (packageManager.resolveActivity(intent,PackageManager.MATCH_DEFAULT_ONLY) != null){
                            //存在录屏授权的Activity 
                            activity.startActivityForResult(intent,requestCode);
                        }else {
                            Toast.makeText(activity,R.string.can_not_record_tip,Toast.LENGTH_SHORT).show();
                        }
                    }

在onActivityResult用户授权处理，还要防止录制操作冲突

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE && resultCode == Activity.RESULT_OK){
            try {
                ScreenUtil.setUpData(resultCode,data);
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            ToastUtil.show(this,"拒绝录屏");
        }
    }

初始化MediaRecorder、创建VirtualDisplay

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void setUpMediaRecorder() {

        mRecordFilePath = getSaveDirectory()  + File.separator+  System.currentTimeMillis() + ".mp4";
        if (mMediaRecorder == null){
            mMediaRecorder = new MediaRecorder();
        }
        //设置音频来源
        mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        //设置视频来源
        mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
        //输出的录屏文件格式
        mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
        //录屏文件路径
        mMediaRecorder.setOutputFile( mRecordFilePath );
        //视频尺寸
        mMediaRecorder.setVideoSize(mRecordWidth, mRecordHeight);
        //音视频编码器
        mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
        mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        //比特率
        mMediaRecorder.setVideoEncodingBitRate((int) (mRecordWidth * mRecordHeight * 3.6));
        //视频帧率
        mMediaRecorder.setVideoFrameRate(20);

        try {
            mMediaRecorder.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }