OpenCameraInterface.java

/*
 * Copyright (C) 2012 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.android.camera.open;

import android.hardware.Camera;
import android.os.Build;
import android.util.Log;

public final class OpenCameraInterface {

    private static final String TAG = OpenCameraInterface.class.getName();

    private OpenCameraInterface() {
    }


    /**
     * Opens the requested camera with {@link android.hardware.Camera#open(int)}, if one exists.
     *
     * @param cameraId camera ID of the camera to use. A negative value means "no preference"
     * @return handle to {@link android.hardware.Camera} that was opened
     */
    public static Camera open(int cameraId) {

        Camera camera;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
            int numCameras = Camera.getNumberOfCameras();
            if (numCameras == 0) {
                Log.w(TAG, "No cameras!");
                return null;
            }

            boolean explicitRequest = cameraId >= 0;

            if (!explicitRequest) {
                // Select a camera if no explicit camera requested
                int index = 0;
                while (index < numCameras) {
                    Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
                    Camera.getCameraInfo(index, cameraInfo);
                    if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
                        break;
                    }
                    index++;
                }

                cameraId = index;
            }

            if (cameraId < numCameras) {
                Log.i(TAG, "Opening camera #" + cameraId);
                camera = Camera.open(cameraId);
            } else {
                if (explicitRequest) {
                    Log.w(TAG, "Requested camera does not exist: " + cameraId);
                    camera = null;
                } else {
                    Log.i(TAG, "No camera facing back; returning camera #0");
                    camera = Camera.open(0);
                }
            }
        } else {
            camera = Camera.open();
        }

        return camera;
    }


    /**
     * Opens a rear-facing camera with {@link android.hardware.Camera#open(int)}, if one exists, or opens camera 0.
     *
     * @return handle to {@link android.hardware.Camera} that was opened
     */
    public static Camera open() {
        return open(-1);
    }

}