本篇文章将围绕自定义控件——CameraSurfaceView来阐述Android Camera的使用详解，这里的Camera不包含Camera2，因为Camera2只适应5.0+的安卓系统，而目前市面上5.0以下的安卓设备还是有相当大的一部分的，所以当前的主流还是使用Camera来开发相机。首先先介绍下CameraSurfaceView，这是一个集拍照，录像，闪光灯，摄像头切换，前后台切换，自适应横竖屏于一体的SurfaceView，而我们平常使用Camera无非也就这几样功能（当然还有例如直播所会使用的Camera预览帧编解码，这个控件暂时没有，后期会补上来），
而CameraSurfaceView使用方法也很简单，如下：
1.赋予程序必要的权限；
2.布局文件中添加
<com.yph.camerasurfaceview.CameraSurfaceView
android:id="@+id/cameraSurfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
或者 new CameraSurfaceView(context),即可。
3.拍照：cameraSurfaceView.capture();
录像：cameraSurfaceView.startRecord();//开始录制
cameraSurfaceView.stopRecord(); //结束录制
//设置录制时长为10秒视频
cameraSurfaceView.startRecord(10000, new MediaRecorder.OnInfoListener() {
@Override
public void onInfo(MediaRecorder mr, int what, int extra) {
cameraSurfaceView.stopRecord();
}
});
闪光灯：cameraSurfaceView.switchLight(boolean open);
前后摄像头的切换：cameraSurfaceView.setDefaultCamera(boolean backCamera);
前后台切换：cameraSurfaceView.setRunBack(boolean b)
4.释放Camera:
@Override
protected void onDestroy() {
super.onDestroy();
cameraSurfaceView.closeCamera();
}
主体类如下（已经包含了上述所有功能代码的实现）：
public class CameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Camera.AutoFocusCallback, View.OnClickListener {
protected static final int[] VIDEO_320 = {320, 240};
protected static final int[] VIDEO_480 = {640, 480};
protected static final int[] VIDEO_720 = {1280, 720};
protected static final int[] VIDEO_1080 = {1920, 1080};
private int screenOritation = Configuration.ORIENTATION_PORTRAIT;
private boolean mOpenBackCamera = true;
private SurfaceHolder mSurfaceHolder;
private SurfaceTexture mSurfaceTexture;
private boolean mRunInBackground = false;
boolean isAttachedWindow = false;
private Camera mCamera;
private Camera.Parameters mParam;
private byte[] previewBuffer;
private int mCameraId;
protected int previewformat = ImageFormat.NV21;
Context context;
public CameraSurfaceView(Context context) {
super(context);
init(context);
}
public CameraSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public CameraSurfaceView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context);
}
private void init(Context context) {
this.context = context;
cameraState = CameraState.START;
if (cameraStateListener != null) {
cameraStateListener.onCameraStateChange(cameraState);
}
openCamera();
if (context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
screenOritation = Configuration.ORIENTATION_LANDSCAPE;
}
mSurfaceHolder = getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceTexture = new SurfaceTexture(10);
setOnClickListener(this);
post(new Runnable() {
@Override
public void run() {
if(!isAttachedWindow){
mRunInBackground = true;
startPreview();
}
}
});
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
isAttachedWindow = true;
}
private void openCamera() {
if (mOpenBackCamera) {
mCameraId = findCamera(false);
} else {
mCameraId = findCamera(true);
}
if (mCameraId == -1) {
mCameraId = 0;
}
try {
mCamera = Camera.open(mCameraId);
} catch (Exception ee) {
mCamera = null;
cameraState = CameraState.ERROR;
if (cameraStateListener != null) {
cameraStateListener.onCameraStateChange(cameraState);
}
}
if (mCamera == null) {
Toast.makeText(context, "打开摄像头失败", Toast.LENGTH_SHORT).show();
return;
}
}
private int findCamera(boolean front) {
int cameraCount;
try {
Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
cameraCount = Camera.getNumberOfCameras();
for (int camIdx = 0; camIdx < cameraCount; camIdx++) {
Camera.getCameraInfo(camIdx, cameraInfo);
int facing = front ? 1 : 0;
if (cameraInfo.facing == facing) {
return camIdx;
}
}
} catch (Exception e) {
e.printStackTrace();
}
return -1;
}
public boolean setDefaultCamera(boolean backCamera) {
if (mOpenBackCamera == backCamera) return false;
if (isRecording) {
Toast.makeText(context, "请先结束录像", Toast.LENGTH_SHORT).show();
return false;
}
mOpenBackCamera = backCamera;
if (mCamera != null) {
closeCamera();
openCamera();
startPreview();
}
return true;
}
public void closeCamera() {
stopRecord();
stopPreview();
releaseCamera();
}
private void releaseCamera() {
try {
if (mCamera != null) {
mCamera.setPreviewCallback(null);
mCamera.setPreviewCallbackWithBuffer(null);
mCamera.stopPreview();
mCamera.release();
mCamera = null;
}
} catch (Exception ee) {
}
}
private boolean isSupportCameraLight() {
boolean mIsSupportCameraLight = false;
try {
if (mCamera != null) {
Camera.Parameters parameter = mCamera.getParameters();
Object a = parameter.getSupportedFlashModes();
if (a == null) {
mIsSupportCameraLight = false;
} else {
mIsSupportCameraLight = true;
}
}
} catch (Exception e) {
mIsSupportCameraLight = false;
e.printStackTrace();
}
return mIsSupportCameraLight;
}
private Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
public synchronized void onPreviewFrame(byte[] data, Camera camera) {
if (data == null) {
releaseCamera();
return;
}
//you can code media here
if (cameraState != CameraState.PREVIEW) {
cameraState = CameraState.PREVIEW;
if (cameraStateListener != null) {
cameraStateListener.onCameraStateChange(cameraState);
}
}
mCamera.addCallbackBuffer(previewBuffer);
}
};
//设置Camera各项参数
private void startPreview() {
if (mCamera == null) return;
try {
mParam = mCamera.getParameters();
mParam.setPreviewFormat(previewformat);
mParam.setRotation(0);
Camera.Size previewSize = CamParaUtil.getSize(mParam.getSupportedPreviewSizes(), 1000,
mCamera.new Size(VIDEO_720[0], VIDEO_720[1]));
mParam.setPreviewSize(previewSize.width, previewSize.height);
int yuv_buffersize = previewSize.width * previewSize.height * ImageFormat.getBitsPerPixel(previewformat) / 8;
previewBuffer = new byte[yuv_buffersize];
Camera.Size pictureSize = CamParaUtil.getSize(mParam.getSupportedPictureSizes(), 1500,
mCamera.new Size(VIDEO_1080[0], VIDEO_1080[1]));
mParam.setPictureSize(pictureSize.width, pictureSize.height);
if (CamParaUtil.isSupportedFormats(mParam.getSupportedPictureFormats(), ImageFormat.JPEG)) {
mParam.setPictureFormat(ImageFormat.JPEG);
mParam.setJpegQuality(100);
}
if (CamParaUtil.isSupportedFocusMode(mParam.getSupportedFocusModes(), FOCUS_MODE_AUTO)) {
mParam.setFocusMode(FOCUS_MODE_AUTO);
}
if (screenOritation != Configuration.ORIENTATION_LANDSCAPE) {
mParam.set("orientation", "portrait");
mCamera.setDisplayOrientation(90);
} else {
mParam.set("orientation", "landscape");
mCamera.setDisplayOrientation(0);
}
if (mRunInBackground) {
mCamera.setPreviewTexture(mSurfaceTexture);
mCamera.addCallbackBuffer(previewBuffer);
// mCamera.setPreviewCallbackWithBuffer(previewCallback);//设置摄像头预览帧回调
} else {
mCamera.setPreviewDisplay(mSurfaceHolder);
// mCamera.setPreviewCallback(previewCallback);//设置摄像头预览帧回调
}
mCamera.setParameters(mParam);
mCamera.startPreview();
if (cameraState != CameraState.START) {
cameraState = CameraState.START;
if (cameraStateListener != null) {
cameraStateListener.onCameraStateChange(cameraState);
}
}
} catch (Exception e) {
releaseCamera();
return;
}
try {
String mode = mCamera.getParameters().getFocusMode();
if (("auto".equals(mode)) || ("macro".equals(mode))) {
mCamera.autoFocus(null);
}
} catch (Exception e) {
}
}
private void stopPreview() {
if (mCamera == null) return;
try {
if (mRunInBackground) {
mCamera.setPreviewCallbackWithBuffer(null);
mCamera.stopPreview();
} else {
mCamera.setPreviewCallback(null);
mCamera.stopPreview();
}
if (cameraState != CameraState.STOP) {
cameraState = CameraState.STOP;
if (cameraStateListener != null) {
cameraStateListener.onCameraStateChange(cameraState);
}
}
} catch (Exception ee) {
}
}
@Override
public void onClick(View v) {
if (mCamera != null) {
mCamera.autoFocus(null);
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
stopPreview();
startPreview();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
stopPreview();
if (mRunInBackground)
startPreview();
}
protected CameraState cameraState;
private CameraStateListener cameraStateListener;
public enum CameraState {
START, PREVIEW, STOP, ERROR
}
public void setOnCameraStateListener(CameraStateListener listener) {
this.cameraStateListener = listener;
}
public interface CameraStateListener {
void onCameraStateChange(CameraState paramCameraState);
}
/**
* ___________________________________前/后台运行______________________________________
**/
public void setRunBack(boolean b) {
if (mCamera == null) return;
if (b == mRunInBackground) return;
if(!b && !isAttachedWindow){
Toast.makeText(context, "Vew未依附在Window,无法显示", Toast.LENGTH_SHORT).show();
return;
}
mRunInBackground = b;
if (b)
setVisibility(View.GONE);
else
setVisibility(View.VISIBLE);
}
/**
* ___________________________________开关闪光灯______________________________________
**/
public void switchLight(boolean open) {
if (mCamera == null) return;
try {
if (mCamera != null) {
if (open) {
Camera.Parameters parameter = mCamera.getParameters();
if (parameter.getFlashMode().equals("off")) {
parameter.setFlashMode("torch");
mCamera.setParameters(parameter);
} else {
parameter.setFlashMode("off");
mCamera.setParameters(parameter);
}
} else {
Camera.Parameters parameter = mCamera.getParameters();
if ((parameter.getFlashMode() != null) &&
(parameter.getFlashMode().equals("torch"))) {
parameter.setFlashMode("off");
mCamera.setParameters(parameter);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* ___________________________________以下为拍照模块______________________________________
**/
public void capture() {
if (mCamera == null) return;
if (!FileUtil.isExternalStorageWritable()) {
Toast.makeText(context, "请插入存储卡", Toast.LENGTH_SHORT).show();
return;
}
mCamera.autoFocus(this);
}
@Override
public void onAutoFocus(boolean success, Camera camera) {
if (success) {
try {
mCamera.takePicture(null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
Matrix matrix = new Matrix();
if (mOpenBackCamera) {
matrix.setRotate(90);
} else {
matrix.setRotate(270);
matrix.postScale(-1, 1);
}
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
FileUtil.saveBitmap(bitmap);
Toast.makeText(context, "拍照成功", Toast.LENGTH_SHORT).show();
startPreview();
}
});
} catch (Exception e) {
if (isRecording) {
Toast.makeText(context, "请先结束录像", Toast.LENGTH_SHORT).show();
}
}
}
}
/**
* ___________________________________以下为视频录制模块______________________________________
**/
MediaRecorder mediaRecorder = new MediaRecorder();
private boolean isRecording = false;
public boolean isRecording() {
return isRecording;
}
public boolean startRecord() {
return startRecord(-1, null);
}
public boolean startRecord(int maxDurationMs, MediaRecorder.OnInfoListener onInfoListener) {
if (mCamera == null) return false;
if (!FileUtil.isExternalStorageWritable()) {
Toast.makeText(context, "请插入存储卡", Toast.LENGTH_SHORT).show();
return false;
}
mCamera.unlock();
mediaRecorder.reset();
mediaRecorder.setCamera(mCamera);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
Camera.Size videoSize = CamParaUtil.getSize(mParam.getSupportedVideoSizes(), 1200,
mCamera.new Size(VIDEO_1080[0], VIDEO_1080[1]));
mediaRecorder.setVideoSize(videoSize.width, videoSize.height);
mediaRecorder.setVideoEncodingBitRate(5 * 1024 * 1024);
// mediaRecorder.setPreviewDisplay(mSurfaceHolder.getSurface());//设置录制预览surface
if (mOpenBackCamera) {
mediaRecorder.setOrientationHint(90);
} else {
if (screenOritation == Configuration.ORIENTATION_LANDSCAPE)
mediaRecorder.setOrientationHint(90);
else
mediaRecorder.setOrientationHint(270);
}
if (maxDurationMs != -1) {
mediaRecorder.setMaxDuration(maxDurationMs);
mediaRecorder.setOnInfoListener(onInfoListener);
}
mediaRecorder.setOutputFile(FileUtil.getMediaOutputPath());
try {
mediaRecorder.prepare();
mediaRecorder.start();
isRecording = true;
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
public void stopRecord() {
if (!isRecording) return;
mediaRecorder.setPreviewDisplay(null);
try {
mediaRecorder.stop();
isRecording = false;
Toast.makeText(context, "视频已保存在根目录", Toast.LENGTH_SHORT).show();
} catch (IllegalStateException e) {
e.printStackTrace();
}
}
/**_________________________________________________________________________________________**/
}
① 需要相机和录音的权限，如果你的target>=23的话，那么你应该判断系统版本，如果大于23则动态申请权限
② 获取到SurfaceView的SurfaceHolder并添加Callback监听，主要为了监听SurfaceView的创建和销毁
在创建的回调方法中设置Camera的各项参数和启动Camera的预览，在销毁的回调中关闭Camera预览；
③ 设置Camera的各项参数是需要其支持的，所以先获取supprot的参数，再从中选择，若非Camera支持的参数
会造成预览黑屏或者崩溃；
④ SurfaceTexture和SurfaceView的区别：
SurfaceTexture是从Android3.0（API 11）加入的一个新类。跟SurfaceView很像，可以从camera preview
或者video decode里面获取图像流（image stream）。SurfaceView从camera读取到的预览（preview）图像流
一定要输出到一个可见的（Visible）SurfaceView上，而SurfaceTexture在接收图像流后，不需要显示出来。
所以在有些需求上，比如在Service后台里面获取camera预览帧进行处理就必须使用SurfaceTexture才能实现。
所以CameraSurfaceView控件的后台运行也是采用SurfaceTexture的，但是这里我要补充一点的是，当有可见的
SurfaceTexture，通过Camera.setPreviewTexture(surfaceTexture)也是可以实现显示Camera预览的。
⑤ 拍照是先调用聚焦，回调成功后在调用Camera的takePicture方法实现的，大部分机型都能做到在录制视频的同
时进行拍照，部分机型不行，所以得先关闭录制，这里已经做了相应的处理。
⑥ 录制视频这块请严格按照格式进行初始化，因为这个初始化环节每个步骤基本是必须的，而且顺序也不能改变
否则会崩溃。
⑦ 前、后台切换时，如果是通过代码里实例CameraSurfaceView对象并且没添加到window是无法切换为前台的，这
种情况适用于在service里面实时获取Camera预览帧的情况，注意添加
mCamera.addCallbackBuffer(previewBuffer);
mCamera.setPreviewCallbackWithBuffer(previewCallback);
在Camera.PreviewCallback previewCallback的onPreviewFrame方法里也要添加
mCamera.addCallbackBuffer(previewBuffer);
⑧ 前后置摄像头切换比较简单，关闭当前Camenra,通过findCamera方法找到摄像头ID并打开，然后开启预览即可。
源码传送门：https://github.com/qq542391099/CameraSurfaceView-master