Android自定义录像功能

自定义录像功能具体步骤大致为：

获取摄像头的ID(现在大部分相机都是前后两个摄像头，你需要根据需求打开前置摄像头或者后置摄像头)，并且使用Camera对象将其打开。
获取一个SurfaceView对象，用于显示预览的图像。
当开始录制视频时(例如用户点击某个按钮)，创建一个MediaRecorder对象
对MediaRecorder对象进行配置
录制视频

获取摄像头ID并打开摄像头

每个摄像头都有ID，分别代表为前置摄像头和后置摄像头，用户可以根据具体的业务需求开启相应的摄像头。
Android API文档中说，开启摄像头，是在UI线程中，并且需要一段时间。
如果你想在onCreate中开启，对好开辟一个线程去处理
或者将摄像头的开启放在onResume中

Getting an instance of the Camera object is the first step in the process of directly controlling the camera. As Android’s own Camera application does, the recommended way to access the camera is to open Camera on a separate thread that’s launched from onCreate(). This approach is a good idea since it can take a while and might bog down the UI thread. In a more basic implementation, opening the camera can be deferred to the onResume() method to facilitate code reuse and keep the flow of control simple.

获取前置摄像头（因为博主的项目只针对于前置摄像头开发）：

private int FindFrontCamera(){int cameraCount = 0;Camera.CameraInfo cameraInfo = new Camera.CameraInfo();cameraCount = Camera.getNumberOfCameras(); for (int camIdx = 0; camIdx < cameraCount;camIdx++) {Camera.getCameraInfo(camIdx, cameraInfo); if ( cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {return camIdx;}}return -1;}

Camera.getNumberOfCameras()可访问的摄像机设备总数，如果没有摄像头，则为0。
Camera.CameraInfo是摄像头的信息，常量里面为CAMERA_FACING_BACK、CAMERA_FACING_FRONT后置摄像头和前置摄像头。
打开摄像头

     mId = FindFrontCamera();try {mCamera = Camera.open(mId);} catch (Exception e) {Toast.makeText(MainActivity.this, "摄像头正在使用", Toast.LENGTH_LONG).show();return;}

开启摄像头的时候应该进行异常检查

Caution: Always check for exceptions when using Camera.open(). Failing to check for exceptions if the camera is in use or does not exist will cause your application to be shut down by the system.
小心：使用Camera.open（）时总是检查异常。如果相机正在使用或不存在，则无法检查异常会导致您的应用程序被系统关闭。

预览图像

当录制视频的时候，用户肯定需要看到自己的图像信息，这时候应该使用SurfaceView对相机捕获的信息进行预览

 public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {private SurfaceHolder mHolder;private Camera mCamera;private int mId;public CameraPreview(Context context, Camera camera, int id) {super(context);mCamera = camera;mId = id;// Install a SurfaceHolder.Callback so we get notified when the// underlying surface is created and destroyed.mHolder = getHolder();mHolder.addCallback(this);// deprecated setting, but required on Android versions prior to 3.0mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);}public void surfaceCreated(SurfaceHolder holder) {// The Surface has been created, now tell the mCamera where to draw the preview.try {mCamera.setPreviewDisplay(holder);mCamera.startPreview();startFaceDetection();} catch (IOException e) {Log.d(TAG, "Error setting mCamera preview: " + e.getMessage());}}public void surfaceDestroyed(SurfaceHolder holder) {// empty. Take care of releasing the Camera preview in your activity.// Surface will be destroyed when we return, so stop the preview.if (mCamera != null) {// Call stopPreview() to stop updating the preview surface.mCamera.stopPreview();}}public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {// If your preview can change or rotate, take care of those events here.// Make sure to stop the preview before resizing or reformatting it.if (mHolder.getSurface() == null){// preview surface does not existreturn;}// stop preview before making changestry {mCamera.stopPreview();} catch (Exception e){// ignore: tried to stop a non-existent preview}// set preview size and make any resize, rotate or reformatting changes here//从Android 2.2（API Level 8）开始，您可以使用setDisplayOrientation（）方法来//设置预览图像的旋转。 为了在用户重定向手机时更改预览方向，//请在surfaceChanged（）方法内，先用Camera.stopPreview（）停止预览，//然后更改方向，然后再次使用Camera.startPreview（）。setCameraDisplayOrientation(MainActivity.this, mId, mCamera);List<Camera.Size> supportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();Camera.Size bestSize = supportedPreviewSizes.get(0);for(int i = 1; i < supportedPreviewSizes.size(); i++){if((supportedPreviewSizes.get(i).width * supportedPreviewSizes.get(i).height) >(bestSize.width * bestSize.height)){bestSize = supportedPreviewSizes.get(i);}}Camera.Parameters parameters = mCamera.getParameters();//注意！！！！！！！！！！！！！！！！！！！！！！//！！！！！！！！！！！！！！！！！！！！！！！！//当设置预览大小的时候，不要自己随意去写值，应该选择在getSupportedPreviewSizes中提供的值parameters.setPreviewSize(bestSize.width, bestSize.height);mCamera.setParameters(parameters);// start preview with new settingstry {mCamera.setPreviewDisplay(mHolder);mCamera.startPreview();} catch (Exception e){Log.d(TAG, "Error starting mCamera preview: " + e.getMessage());}}public void setCameraDisplayOrientation(AppCompatActivity activity,int cameraId, android.hardware.Camera camera) {android.hardware.Camera.CameraInfo info =new android.hardware.Camera.CameraInfo();android.hardware.Camera.getCameraInfo(cameraId, info);int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();int degrees = 0;switch (rotation) {case Surface.ROTATION_0: degrees = 0; break;case Surface.ROTATION_90: degrees = 90; break;case Surface.ROTATION_180: degrees = 180; break;case Surface.ROTATION_270: degrees = 270; break;}int result;if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {result = (info.orientation + degrees) % 360;result = (360 - result) % 360;  // compensate the mirror} else {  // back-facingresult = (info.orientation - degrees + 360) % 360;}camera.setDisplayOrientation(result);}}

创建MediaRecorder对象并对其进行配置

private boolean prepareVideoRecorder(Camera mCamera){mMediaRecorder = new MediaRecorder();// Step 1: Unlock and set camera to MediaRecordermCamera.unlock();mMediaRecorder.setCamera(mCamera);// Step 2: Set sourcesmMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);// Step 3: Set a CamcorderProfile (requires API Level 8 or higher)// 注意这里，最好和预览设置的尺寸保持一直，否则录制时的视频会出现放大或缩小的情况mMediaRecorder.setProfile(CamcorderProfile.get(mId, CamcorderProfile.QUALITY_1080P));// Step 4: Set output filemPath = getOutputMediaFile(MEDIA_TYPE_VIDEO).toString();System.out.println("path = " + mPath);mMediaRecorder.setOutputFile(mPath);// Step 5: Set the preview outputSurface surface = mPreview.getHolder().getSurface();mMediaRecorder.setPreviewDisplay(surface);// Step 6: Prepare configured MediaRecordertry {mMediaRecorder.prepare();} catch (IllegalStateException e) {Log.d(TAG, "IllegalStateException preparing MediaRecorder: " + e.getMessage());releaseMediaRecorder();return false;} catch (IOException e) {Log.d(TAG, "IOException preparing MediaRecorder: " + e.getMessage());releaseMediaRecorder();return false;}return true;}

录制视频

录制视频结束后应该调用mCamera.lock()方法

注意
大部分相机功能都处在Camera.Parameters里面，可以通过mCamera.getParameters();方法去获得
如图

不同的设备使用相机的时候，有的功能可以使用，有的功能不能使用(博主的设备不支持自动对焦）。所以要在一些功能使用前，判断是否支持这个功能)。

// get Camera parameters
Camera.Parameters params = mCamera.getParameters();List<String> focusModes = params.getSupportedFocusModes();
if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {// Autofocus mode is supportedparameters.setFocusMode(Parameters.FOCUS_MODE_AUTO);mCamera.setParameters(parameters);mCamera.autoFocus(null);
}

大体就是这个流程
具体代码，我实在是没有C币了，我也很无奈

微信公众号

欢迎赞赏

QQ群：365473065