Android静默拍照实现

1.申请权限（6.0以后要动态申请）

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

2.创建相机工具类 CameraPreview：

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private SurfaceHolder mHolder;
    private Camera mCamera;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        //初始化Camera对象
        mCamera = camera;
        //得到SurfaceHolder对象
        mHolder = getHolder();
        //添加回调，得到Surface的三个声明周期方法
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            //设置预览方向
            mCamera.setDisplayOrientation(90);
            //把这个预览效果展示在SurfaceView上面
            mCamera.setPreviewDisplay(holder);
            //开启预览效果
            mCamera.startPreview();
        } catch (IOException e) {
//            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }

    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        if (holder.getSurface() == null) {
            return;
        }
        //停止预览效果
        mCamera.stopPreview();
        //重新设置预览效果
        try {
            mCamera.setPreviewDisplay(mHolder);
        } catch (IOException e) {
            e.printStackTrace();
        }
        mCamera.startPreview();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }
}

3.创建xml文件 （要想用户无感拍照，可把视图宽高调为0.1dp或者隐藏在别的页面之下）：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <FrameLayout
        android:id="@+id/camera_frame"
        android:layout_width="match_parent"
        android:layout_height="500dp">
    </FrameLayout>

</LinearLayout>

4.主类实现静默拍照：

public class CameraActivity  extends BaseActivity{

    private FrameLayout cameraFrame;
    private   Camera mCamera;
    private TextView cameraTv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera);


        cameraFrame = (FrameLayout) findViewById(R.id.camera_frame);
        cameraTv = (TextView) findViewById(R.id.camera_tv);

        int numberOfCameras = Camera.getNumberOfCameras();// 获取摄像头个数
        //遍历摄像头信息
        for (int cameraId = 0; cameraId < numberOfCameras; cameraId++) {
            Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
            Camera.getCameraInfo(cameraId, cameraInfo);
            if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {//前置摄像头
                mCamera = Camera.open(cameraId);//打开摄像头
            }
        }

        CameraPreview mPreview = new CameraPreview(this, mCamera);
        cameraFrame.addView(mPreview);
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);  // 设置1秒后自动拍照，可调节
                    //得到照相机的参数
                    Camera.Parameters parameters = mCamera.getParameters();
                    //图片的格式
                    parameters.setPictureFormat(ImageFormat.JPEG);
                    //预览的大小是多少
                    parameters.setPreviewSize(800, 400);
                    //设置对焦模式，自动对焦
                    parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                    //对焦成功后，自动拍照
                    mCamera.autoFocus(new Camera.AutoFocusCallback() {
                        @Override
                        public void onAutoFocus(boolean success, Camera camera) {
                            if (success) {
                                //获取照片
                                mCamera.takePicture(null, null, mPictureCallback);
                            }
                        }
                    });
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();

        });
    }

    @Override
    protected void onStart() {
        super.onStart();

    }

    //获取照片中的接口回调
    Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            FileOutputStream fos = null;
            String mFilePath = Environment.getExternalStorageDirectory().getPath() + File.separator + "tt005.png";
            //文件
            File tempFile = new File(mFilePath);
            try {
                //
                fos = new FileOutputStream(tempFile);
                fos.write(data);

            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                //实现连续拍多张的效果
//                mCamera.startPreview();
//                if (fos != null) {
//                    try {
//                        fos.close();
//                    } catch (IOException e) {
//                        e.printStackTrace();
//                    }
//                }
            }

        }
    };
}