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.xiaomi.xms.sales.zxing.camera.open;

import android.hardware.Camera;

import com.xiaomi.xms.sales.util.LogUtil;

/**
 * Provides an abstracted means to open a {@link Camera}. The API changes over
 * Android API versions and this allows the app to use newer API methods while
 * retaining backwards-compatible behavior.
 */
public final class OpenCameraInterface {

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

    private OpenCameraInterface() {
    }

    /**
     * Opens a rear-facing camera with {@link Camera#open(int)}, if one exists, or opens camera 0.
     */
    public static Camera open() {
      
      int numCameras = Camera.getNumberOfCameras();
      if (numCameras == 0) {
        LogUtil.w(TAG, "No cameras!");
        return null;
      }

      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++;
      }
      
      Camera camera;
      if (index < numCameras) {
          LogUtil.i(TAG, "Opening camera #" + index);
        camera = Camera.open(index);
      } else {
          LogUtil.i(TAG, "No camera facing back; returning camera #0");
        camera = Camera.open(0);
      }

      return camera;
    }

}