Custom Camera(自定义相机)

偏执的太偏执、 2022-06-02 22:36 383阅读 0赞

最近倒腾了自定义相机的一些东西，中间也遇到了很多麻烦，查阅了很多别人写的博客，也看了相关的API，进过几番折腾最后代码才调试成功。写这篇博客，一方面是想把自己的东西分享给大家，能够一起交流；另一方面，也想通过这种方法加强自己记忆。

首先创建一个基本的camera预览类CameraPreview。参考[点击打开链接][Link 1]，该类继承SurfaceView.Callback接口类，并且需要实现里面的接口方法以便监听SurfaceView控件的创建以及销毁事件的回调，在回调方法中关联相机预览显示。并且要在相应得布局文件中添加SurfaceView控件。

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback{
    
        private Camera mCamera;
        private SurfaceHolder mHolder;
        public CameraPreview(Context context, Camera camera,SurfaceView surfaceView) {
            super(context);
            mCamera = camera;
            mHolder = surfaceView.getHolder();
            mHolder.addCallback(this);//实现surfaceHolder.Callback接口
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }
    
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            showCameraView(mCamera,mHolder);
        }
    
        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            if (mCamera != null) {
                mCamera.stopPreview();
                if (mHolder != null) {
                    showCameraView(mCamera,mHolder);
                }
            }
        }
    
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            //clearCamera();//使用构造器这种方法的时候此处不能clearCamera
        }
        private void showCameraView(Camera camera, SurfaceHolder holder)
        {
            try {
                camera.setPreviewDisplay(holder);
                /**眼镜可以不用旋转*/
                //camera.setDisplayOrientation(90);//旋转90度
                camera.startPreview();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        /**释放相机的内存*/
        private void clearCamera(){
            // 释放hold资源
            if (mCamera != null) {
                // 停止预览
                mCamera.setPreviewCallback(null);
                mCamera.stopPreview();
                // 释放相机资源
                mCamera.release();
                mCamera = null;
            }
        }
    }

第二步是新建CustomCamera活动，这里面要完成以下几个步骤：

1、检查设备是否有相机

/** 检查是否存在相机*/
        private boolean checkCameraHardware(Context context) {
            if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
                // this device has a camera
                 return true;
            } else {
                // no camera on this device
               return false;
            }
        }

2、获取相机

/** 获得Camera的实例*/
        private Camera getCamera(){
            Camera camera;
            try{
                camera = Camera.open();
            }catch (Exception e){
                camera = null;
                e.printStackTrace();
            }
            return camera;
        }

3、在onCreate()方法中获取SurfaceView的一个实例，然后在获取CameraPreview的实例，并将SurfaceView的实例和其绑定，实现相机的预览功能

@Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.custom_camera);
            surfaceView = findViewById(R.id.surface_view);
    
            if(checkCameraHardware(CustomCamera.this)){
                //mCamera = getCamera();
                //安卓6.0以后权限更严，在使用camera时要运行时权限询问
                if(ContextCompat.checkSelfPermission(CustomCamera.this, Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED){
                    ActivityCompat.requestPermissions(CustomCamera.this,
                            new String[]{Manifest.permission.CAMERA},1);
                }else {
                    mCamera = getCamera();
                }
            }
            new CameraPreview(CustomCamera.this,mCamera,surfaceView);
            Button capture = findViewById(R.id.capture);
            capture.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d(TAG, "onClick");
                    takePhoto();
                }
            });
    
        }

4接下来就是拍照了，在代码中你应该实现一个监听回调来捕获用户拍照的行为。代码中调用Camera.takePciture()方法来进行拍照。该方法接受三个参数，第一个参数ShutterCallback响应快门的接口，第二个参数PictureCallback接收raw格式的图片数据，第三个参数PictureCallback接收jpeg格式的图片数据。为了保存图片数据，你需要分别实现以上三个接口。此处我们暂且实现第三个PictureCallback接口回调

public void takePhoto(){
            mCamera.takePicture(null,null,mPicture);
            /**眼镜的Camera没有对焦功能（只是可能没有），所以不能调用AutoFocus
             * 但是图片的格式在眼镜上应该是可以设置的，你可以尝试设置格式 */
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPictureFormat(ImageFormat.JPEG);//设置相片的格式
            parameters.setPictureSize(1600,860);
            parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
            //Toast.makeText(CustomCamera.this,"拍照成功",Toast.LENGTH_SHORT).show();
            mCamera.autoFocus(new Camera.AutoFocusCallback() {
                @Override
                public void onAutoFocus(boolean success, Camera camera) {
                    if(success){
    
                        Log.d(TAG, "对焦成功");
                    }
                }
            });
        }

5在onPictureTaken()中，图片是存储在data这个byte\[\]数组中，通过getOutputMediaFile()方法来存储图片，为了能够使图片能够显示我们要将图片的位置通过intent来传递给MainActivity

private Camera.PictureCallback mPicture = new Camera.PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                File mFile = getOutputMediaFile();
                //camera.startPreview();
                if (mFile == null) {
                    Log.d(TAG, "takephoto");
                    return;
                }
                try{
                    FileOutputStream fos = new FileOutputStream(mFile);
                    fos.write(data);
                    fos.close();
                    Intent intent = new Intent();
                    // 传递路径
                    intent.putExtra("path", mFile.getAbsolutePath());
                    Log.d(TAG, mFile.getAbsolutePath());
                    setResult(0,intent);
                    finish();
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        };

/** Create a File for saving an image or video */
        private File getOutputMediaFile(){
            // To be safe, you should check that the SDCard is mounted
            // using Environment.getExternalStorageState() before doing this.
            File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                    Environment.DIRECTORY_PICTURES), "MyCameraApp");
            // This location works best if you want the created images to be shared
            // between applications and persist after your app has been uninstalled.
    
            // Create the storage directory if it does not exist
            if (! mediaStorageDir.exists()){
                if (! mediaStorageDir.mkdirs()){
                    Log.d(TAG, "failed to create directory");
                    return null;
                }
            }
            // Create a media file name
            String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
            File mediaFile;
            try{
                mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                        "IMG_"+ timeStamp + ".jpg");
            }catch (Exception e){
                mediaFile = null;
                e.printStackTrace();
            }
            return mediaFile;
        }

6我们在MainActivity中获取图片并显示在imageview中。

private static final int TAKEPHOTO = 100;
        private static final String TAG = "MainActivity";
        private ImageView photoView;
        private Matrix matrix;

@Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            photoView = findViewById(R.id.photo_view);
            Button takePhoto = findViewById(R.id.take_photo);
            takePhoto.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(MainActivity.this,CustomCamera.class);
                    startActivityForResult(intent,TAKEPHOTO);
                }
            });
        }

@Override
        protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            switch (requestCode){
                case 100:
                    if (resultCode == 0){
                        String path = data.getStringExtra("path");
                        Log.d(TAG, path);
                        //路径为内部存储空间/Pictures/MyCameraApp
                        BitmapFactory.Options options = new BitmapFactory.Options();
                        options.inJustDecodeBounds = true;//如果设置为true，解码器将返回null（没有位图）
                        BitmapFactory.decodeFile(path, options);
                        ImageSize imageSize = getImageViewSize(photoView);
                        options.inSampleSize = caculateInSampleSize(options,
                                imageSize.width, imageSize.height);
    
                        // 使用获得到的InSampleSize再次解析图片
                        options.inJustDecodeBounds = false;
                        Bitmap bitmap = BitmapFactory.decodeFile(path, options);
                        // 因为画面预览时是旋转后显示的，所以保存的图片也需要旋转90度
                        /**下面注释的代码是将上面得到的bitmap旋转90度，
                         * 但是眼镜可以不用旋转就可以使用了*/
                        matrix = new Matrix();
                        matrix.setRotate(90);
                        // 创建一个新的Bitmap
                        bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
                        photoView.setImageBitmap(bitmap);
                    }
            }
        }

7获取的图片要进行处理，这里通过BitmapFactory.Options类来处理，并且要计算图片尺寸的大小，由于获取的bitmap是横的，还要通过Matrix旋转一下。最后将图片Imageview的setImageBitmap()方法将图片显示在photoview中。

/** 根据需求的宽和高以及图片实际的宽和高计算SampleSize*/
        public static int caculateInSampleSize(BitmapFactory.Options options, int reqWidth,
                                               int reqHeight) {
            int width = options.outWidth;//bitmap的宽度
            int height = options.outHeight;
    
            int inSampleSize = 1;
    
            if (width > reqWidth || height > reqHeight) {
                int widthRadio = Math.round(width * 1.0f / reqWidth);
                int heightRadio = Math.round(height * 1.0f / reqHeight);
    
                inSampleSize = Math.max(widthRadio, heightRadio);
            }
    
            return inSampleSize;
        }
    
        public static ImageSize getImageViewSize(ImageView imageView) {
    
            ImageSize imageSize = new ImageSize();
            DisplayMetrics displayMetrics = imageView.getContext().getResources()
                    .getDisplayMetrics();
    
            LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) imageView.getLayoutParams();
    
            int width = imageView.getWidth();// 获取imageview的实际宽度
            if (width <= 0) {
                width = lp.width;// 获取imageview在layout中声明的宽度
            }
    
            if (width <= 0) {
                width = displayMetrics.widthPixels;
            }
    
            int height = imageView.getHeight();// 获取imageview的实际高度
            if (height <= 0) {
                height = lp.height;// 获取imageview在layout中声明的宽度
            }
    
            if (height <= 0) {
                height = displayMetrics.heightPixels;
            }
            imageSize.width = width;
            imageSize.height = height;
    
            return imageSize;
        }
        /**通过创建一个内部类来存储width、height*/
        public static class ImageSize {
            int width;
            int height;
        }

上面就是我创建Cumtom Camera的过程，第一次写博客写的不好的地方还请大家提出宝贵意见。另附上源码。 [源码地址][Link 2]

[Link 1]: http://blog.csdn.net/feiduclear_up/article/details/51968975
[Link 2]: http://download.csdn.net/download/zengtudou/10155032