CameraPreviewFragment

CameraPreview.java

/*
* Copyright 2015 The Android Open Source Project
*
* 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 permissions.dispatcher.sample.camera;

import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.io.IOException;

/**
 * Camera preview that displays a {@link Camera}.
 *
 * Handles basic lifecycle methods to display and stop the preview.
 * <p>
 * Implementation is based directly on the documentation at
 * http://developer.android.com/guide/topics/media/camera.html
 */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    private static final String TAG = "CameraPreview";
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private Camera.CameraInfo mCameraInfo;
    private int mDisplayOrientation;

    public CameraPreview(Context context, Camera camera, Camera.CameraInfo cameraInfo,
            int displayOrientation) {
        super(context);

        // Do not initialise if no camera has been set
        if (camera == null || cameraInfo == null) {
            return;
        }
        mCamera = camera;
        mCameraInfo = cameraInfo;
        mDisplayOrientation = displayOrientation;

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
            Log.d(TAG, "Camera preview started.");
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // empty. Take care of releasing the Camera preview in your activity.
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.

        if (mHolder.getSurface() == null) {
            // preview surface does not exist
            Log.d(TAG, "Preview surface does not exist");
            return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
            Log.d(TAG, "Preview stopped.");
        } catch (Exception e) {
            // ignore: tried to stop a non-existent preview
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }

        int orientation = calculatePreviewOrientation(mCameraInfo, mDisplayOrientation);
        mCamera.setDisplayOrientation(orientation);

        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();
            Log.d(TAG, "Camera preview started.");
        } catch (Exception e) {
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

    /**
     * Calculate the correct orientation for a {@link Camera} preview that is displayed on screen.
     *
     * Implementation is based on the sample code provided in
     * {@link Camera#setDisplayOrientation(int)}.
     */
    public static int calculatePreviewOrientation(Camera.CameraInfo info, int rotation) {
        int degrees = 0;

        switch (rotation) {
            case Surface.ROTATION_0:
                degrees = 0;
                break;
            case Surface.ROTATION_90:
                degrees = 90;
                break;
            case Surface.ROTATION_180:
                degrees = 180;
                break;
            case Surface.ROTATION_270:
                degrees = 270;
                break;
        }

        int result;
        if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
            result = (info.orientation + degrees) % 360;
            result = (360 - result) % 360;  // compensate the mirror
        } else {  // back-facing
            result = (info.orientation - degrees + 360) % 360;
        }

        return result;
    }
}

CameraPreviewFragment.java

/*
* Copyright 2015 The Android Open Source Project
*
* 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 permissions.dispatcher.sample.camera;

import android.hardware.Camera;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import permissions.dispatcher.sample.R;

/**
 * Displays a {@link CameraPreview} of the first {@link Camera}.
 * An error message is displayed if the Camera is not available.
 * <p>
 * This Fragment is only used to illustrate that access to the Camera API has been granted (or
 * denied) as part of the runtime permissions model. It is not relevant for the use of the
 * permissions API.
 * <p>
 * Implementation is based directly on the documentation at
 * http://developer.android.com/guide/topics/media/camera.html
 */
public class CameraPreviewFragment extends Fragment {

    private static final String TAG = "CameraPreview";

    /**
     * Id of the camera to access. 0 is the first camera.
     */
    private static final int CAMERA_ID = 0;

    private CameraPreview mPreview;
    private Camera mCamera;

    public static CameraPreviewFragment newInstance() {
        return new CameraPreviewFragment();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        // Open an instance of the first camera and retrieve its info.
        mCamera = getCameraInstance(CAMERA_ID);
        Camera.CameraInfo cameraInfo = null;

        if (mCamera != null) {
            // Get camera info only if the camera is available
            cameraInfo = new Camera.CameraInfo();
            Camera.getCameraInfo(CAMERA_ID, cameraInfo);
        }

        View root = inflater.inflate(R.layout.fragment_camera, null);

        // Get the rotation of the screen to adjust the preview image accordingly.
        final int displayRotation = getActivity().getWindowManager().getDefaultDisplay()
                .getRotation();

        // Create the Preview view and set it as the content of this Activity.
        mPreview = new CameraPreview(getActivity(), mCamera, cameraInfo, displayRotation);
        FrameLayout preview = (FrameLayout) root.findViewById(R.id.camera_preview);
        preview.addView(mPreview);

        return root;
    }

    @Override
    public void onPause() {
        super.onPause();
        // Stop camera access
        releaseCamera();
    }

    /** A safe way to get an instance of the Camera object. */
    public static Camera getCameraInstance(int cameraId) {
        Camera c = null;
        try {
            c = Camera.open(cameraId); // attempt to get a Camera instance
        } catch (Exception e) {
            // Camera is not available (in use or does not exist)
            Log.d(TAG, "Camera " + cameraId + " is not available: " + e.getMessage());
        }
        return c; // returns null if camera is unavailable
    }

    private void releaseCamera() {
        if (mCamera != null) {
            mCamera.release();        // release the camera for other applications
            mCamera = null;
        }
    }
}