com.iwuvhugs.seekgame.PhotoFragment.java Source code

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Here is the source code for com.iwuvhugs.seekgame.PhotoFragment.java

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/*
 * Copyright 2014 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 com.iwuvhugs.seekgame;

import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.CaptureResult;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.media.Image;
import android.media.ImageReader;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.support.annotation.NonNull;
import android.support.v13.app.FragmentCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.LayoutInflater;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.Toast;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

public class PhotoFragment extends Fragment
        implements View.OnClickListener, FragmentCompat.OnRequestPermissionsResultCallback {

    private static final String TAG = PhotoFragment.class.getSimpleName();

    /**
     * Conversion from screen rotation to JPEG orientation.
     */
    private static final SparseIntArray ORIENTATIONS = new SparseIntArray();

    // Rotate image output a little bit :)
    static {
        ORIENTATIONS.append(Surface.ROTATION_0, 90);
        ORIENTATIONS.append(Surface.ROTATION_90, 0);
        ORIENTATIONS.append(Surface.ROTATION_180, 270);
        ORIENTATIONS.append(Surface.ROTATION_270, 180);
    }

    private static final int REQUEST_CAMERA_PERMISSION = 1;
    private static final String FRAGMENT_DIALOG = "dialog";

    /**
     * Camera states
     */
    private static final int STATE_PREVIEW = 0; // Showing camera preview.
    private static final int STATE_WAITING_LOCK = 1; // Waiting for the focus to be locked
    private static final int STATE_WAITING_PRECAPTURE = 2; // Waiting for the exposure to be precapture state.
    private static final int STATE_WAITING_NON_PRECAPTURE = 3; // Waiting for the exposure state to be something other than precapture.
    private static final int STATE_PICTURE_TAKEN = 4; // Picture was taken

    /**
     * Max preview width that is guaranteed by Camera2 API
     */
    private static final int MAX_PREVIEW_WIDTH = 1920;

    /**
     * Max preview height that is guaranteed by Camera2 API
     */
    private static final int MAX_PREVIEW_HEIGHT = 1080;

    /**
     * {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a
     * {@link TextureView}.
     */
    private final TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() {

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) {
            openCamera(width, height);
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) {
            configureTransform(width, height);
        }

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) {
            return true;
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture texture) {
        }

    };

    private String mCameraId; // ID of the current {@link CameraDevice}.
    private TextureView mTextureView; // {@link TextureView} for camera preview.
    private CameraCaptureSession mCaptureSession; // {@link CameraCaptureSession } for camera preview.
    private CameraDevice mCameraDevice; // A reference to the opened {@link CameraDevice}.
    private Size mPreviewSize; // The {@link Size} of camera preview.

    private ImageButton takePictureButton;
    private ImageView photoView;
    private LinearLayout progressInfoView;

    /**
     * {@link CameraDevice.StateCallback} is called when {@link CameraDevice} changes its state.
     */
    private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

        @Override
        public void onOpened(@NonNull CameraDevice cameraDevice) {
            // This method is called when the camera is opened.  We start camera preview here.
            mCameraOpenCloseLock.release();
            mCameraDevice = cameraDevice;
            createCameraPreviewSession();
        }

        @Override
        public void onDisconnected(@NonNull CameraDevice cameraDevice) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
        }

        @Override
        public void onError(@NonNull CameraDevice cameraDevice, int error) {
            mCameraOpenCloseLock.release();
            cameraDevice.close();
            mCameraDevice = null;
            Activity activity = getActivity();
            if (null != activity) {
                activity.finish();
            }
        }

    };

    private HandlerThread mBackgroundThread; // An additional thread for running tasks that shouldn't block the UI.
    private Handler mBackgroundHandler; // A {@link Handler} for running tasks in the background.
    private ImageReader mImageReader; // {@link ImageReader} that handles still image capture.
    private File mFile; // This is the output file for our picture.

    /**
     * This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a
     * still image is ready to be saved.
     */
    private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {

        @Override
        public void onImageAvailable(ImageReader reader) {
            mBackgroundHandler.post(new ImageSaver(reader.acquireNextImage(), mFile));
        }

    };

    private CaptureRequest.Builder mPreviewRequestBuilder; // {@link CaptureRequest.Builder} for the camera preview
    private CaptureRequest mPreviewRequest; // {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder}
    private int mState = STATE_PREVIEW; // The current state of camera state for taking pictures.
    private Semaphore mCameraOpenCloseLock = new Semaphore(1); // A {@link Semaphore} to prevent the app from exiting before closing the camera.
    private boolean mFlashSupported; // Whether the current camera device supports Flash or not.

    /**
     * A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture.
     */
    private CameraCaptureSession.CaptureCallback mCaptureCallback = new CameraCaptureSession.CaptureCallback() {

        private void process(CaptureResult result) {
            switch (mState) {
            case STATE_PREVIEW: {
                // We have nothing to do when the camera preview is working normally.
                break;
            }
            case STATE_WAITING_LOCK: {
                Integer afState = result.get(CaptureResult.CONTROL_AF_STATE);
                if (afState == null) {
                    captureStillPicture();
                } else if (CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED == afState
                        || CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED == afState) {
                    // CONTROL_AE_STATE can be null on some devices
                    Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
                    if (aeState == null || aeState == CaptureResult.CONTROL_AE_STATE_CONVERGED) {
                        mState = STATE_PICTURE_TAKEN;
                        captureStillPicture();
                    } else {
                        runPrecaptureSequence();
                    }
                }
                break;
            }
            case STATE_WAITING_PRECAPTURE: {
                // CONTROL_AE_STATE can be null on some devices
                Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
                if (aeState == null || aeState == CaptureResult.CONTROL_AE_STATE_PRECAPTURE
                        || aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED) {
                    mState = STATE_WAITING_NON_PRECAPTURE;
                }
                break;
            }
            case STATE_WAITING_NON_PRECAPTURE: {
                // CONTROL_AE_STATE can be null on some devices
                Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
                if (aeState == null || aeState != CaptureResult.CONTROL_AE_STATE_PRECAPTURE) {
                    mState = STATE_PICTURE_TAKEN;
                    captureStillPicture();
                }
                break;
            }
            }
        }

        @Override
        public void onCaptureProgressed(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request,
                @NonNull CaptureResult partialResult) {
            process(partialResult);
        }

        @Override
        public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request,
                @NonNull TotalCaptureResult result) {
            process(result);
        }

    };

    /**
     * Shows a {@link Toast} on the UI thread.
     *
     * @param text The message to show
     */
    private void showToast(final String text) {
        final Activity activity = getActivity();
        if (activity != null) {
            activity.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(activity, text, Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

    /**
     * Given {@code choices} of {@code Size}s supported by a camera, choose the smallest one that
     * is at least as large as the respective texture view size, and that is at most as large as the
     * respective max size, and whose aspect ratio matches with the specified value. If such size
     * doesn't exist, choose the largest one that is at most as large as the respective max size,
     * and whose aspect ratio matches with the specified value.
     *
     * @param choices           The list of sizes that the camera supports for the intended output
     *                          class
     * @param textureViewWidth  The width of the texture view relative to sensor coordinate
     * @param textureViewHeight The height of the texture view relative to sensor coordinate
     * @param maxWidth          The maximum width that can be chosen
     * @param maxHeight         The maximum height that can be chosen
     * @param aspectRatio       The aspect ratio
     * @return The optimal {@code Size}, or an arbitrary one if none were big enough
     */
    private static Size chooseOptimalSize(Size[] choices, int textureViewWidth, int textureViewHeight, int maxWidth,
            int maxHeight, Size aspectRatio) {

        // Collect the supported resolutions that are at least as big as the preview Surface
        List<Size> bigEnough = new ArrayList<>();
        // Collect the supported resolutions that are smaller than the preview Surface
        List<Size> notBigEnough = new ArrayList<>();
        int w = aspectRatio.getWidth();
        int h = aspectRatio.getHeight();
        for (Size option : choices) {
            if (option.getWidth() <= maxWidth && option.getHeight() <= maxHeight
                    && option.getHeight() == option.getWidth() * h / w) {
                if (option.getWidth() >= textureViewWidth && option.getHeight() >= textureViewHeight) {
                    bigEnough.add(option);
                } else {
                    notBigEnough.add(option);
                }
            }
        }

        // Pick the smallest of those big enough. If there is no one big enough, pick the
        // largest of those not big enough.
        if (bigEnough.size() > 0) {
            return Collections.min(bigEnough, new CompareSizesByArea());
        } else if (notBigEnough.size() > 0) {
            return Collections.max(notBigEnough, new CompareSizesByArea());
        } else {
            Log.e(TAG, "Couldn't find any suitable preview size");
            return choices[0];
        }
    }

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.photo_fragment, container, false);

        photoView = (ImageView) view.findViewById(R.id.main_image);
        takePictureButton = (ImageButton) view.findViewById(R.id.picture);
        takePictureButton.setOnClickListener(this);
        mTextureView = (TextureView) view.findViewById(R.id.texture);
        progressInfoView = (LinearLayout) view.findViewById(R.id.progress);

        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mFile = new File(getActivity().getExternalFilesDir(null), "pic.jpg");
    }

    @Override
    public void onResume() {
        super.onResume();
        startBackgroundThread();

        // When the screen is turned off and turned back on, the SurfaceTexture is already
        // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
        // a camera and start preview from here (otherwise, we wait until the surface is ready in
        // the SurfaceTextureListener).
        if (mTextureView.isAvailable()) {
            openCamera(mTextureView.getWidth(), mTextureView.getHeight());
        } else {
            mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
        }
    }

    @Override
    public void onPause() {
        closeCamera();
        stopBackgroundThread();
        super.onPause();
    }

    private void requestCameraPermission() {
        if (FragmentCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
            new ConfirmationDialog().show(getChildFragmentManager(), FRAGMENT_DIALOG);
        } else {
            FragmentCompat.requestPermissions(this, new String[] { Manifest.permission.CAMERA },
                    REQUEST_CAMERA_PERMISSION);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
            @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults.length != 1 || grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                ErrorDialog.newInstance("This sample needs camera permission.").show(getChildFragmentManager(),
                        FRAGMENT_DIALOG);
            }
        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    /**
     * Sets up member variables related to camera.
     *
     * @param width  The width of available size for camera preview
     * @param height The height of available size for camera preview
     */
    private void setUpCameraOutputs(int width, int height) {
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            for (String cameraId : manager.getCameraIdList()) {
                CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);

                // We don't use a front facing camera in this sample.
                Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
                if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
                    continue;
                }

                StreamConfigurationMap map = characteristics
                        .get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
                if (map == null) {
                    continue;
                }

                // For still image captures, we use the largest available size.
                Size largest = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)),
                        new CompareSizesByArea());
                mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(), ImageFormat.JPEG,
                        /*maxImages*/2);
                mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, mBackgroundHandler);

                // Find out if we need to swap dimension to get the preview size relative to sensor
                // coordinate.
                int displayRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
                int sensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
                boolean swappedDimensions = false;
                switch (displayRotation) {
                case Surface.ROTATION_0:
                case Surface.ROTATION_180:
                    if (sensorOrientation == 90 || sensorOrientation == 270) {
                        swappedDimensions = true;
                    }
                    break;
                case Surface.ROTATION_90:
                case Surface.ROTATION_270:
                    if (sensorOrientation == 0 || sensorOrientation == 180) {
                        swappedDimensions = true;
                    }
                    break;
                default:
                    Log.e(TAG, "Display rotation is invalid: " + displayRotation);
                }

                Point displaySize = new Point();
                activity.getWindowManager().getDefaultDisplay().getSize(displaySize);
                int rotatedPreviewWidth = width;
                int rotatedPreviewHeight = height;
                int maxPreviewWidth = displaySize.x;
                int maxPreviewHeight = displaySize.y;

                if (swappedDimensions) {
                    rotatedPreviewWidth = height;
                    rotatedPreviewHeight = width;
                    maxPreviewWidth = displaySize.y;
                    maxPreviewHeight = displaySize.x;
                }

                if (maxPreviewWidth > MAX_PREVIEW_WIDTH) {
                    maxPreviewWidth = MAX_PREVIEW_WIDTH;
                }

                if (maxPreviewHeight > MAX_PREVIEW_HEIGHT) {
                    maxPreviewHeight = MAX_PREVIEW_HEIGHT;
                }

                // Danger, W.R.! Attempting to use too large a preview size could  exceed the camera
                // bus' bandwidth limitation, resulting in gorgeous previews but the storage of
                // garbage capture data.
                mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), rotatedPreviewWidth,
                        rotatedPreviewHeight, maxPreviewWidth, maxPreviewHeight, largest);

                // Check if the flash is supported.
                Boolean available = characteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
                mFlashSupported = available == null ? false : available;

                mCameraId = cameraId;
                return;
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            // Currently an NPE is thrown when the Camera2API is used but not supported on the
            // device this code runs.
            ErrorDialog.newInstance("This device doesn\\'t support Camera2 API").show(getChildFragmentManager(),
                    FRAGMENT_DIALOG);
        }
    }

    /**
     * Opens the camera specified by {@link PhotoFragment#mCameraId}.
     */
    private void openCamera(int width, int height) {
        if (ContextCompat.checkSelfPermission(getActivity(),
                Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            requestCameraPermission();
            return;
        }

        setUpCameraOutputs(width, height);
        configureTransform(width, height);
        Activity activity = getActivity();
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
                throw new RuntimeException("Time out waiting to lock camera opening.");
            }
            manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
        }
    }

    /**
     * Closes the current {@link CameraDevice}.
     */
    private void closeCamera() {
        try {
            mCameraOpenCloseLock.acquire();
            if (null != mCaptureSession) {
                mCaptureSession.close();
                mCaptureSession = null;
            }
            if (null != mCameraDevice) {
                mCameraDevice.close();
                mCameraDevice = null;
            }
            if (null != mImageReader) {
                mImageReader.close();
                mImageReader = null;
            }
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera closing.", e);
        } finally {
            mCameraOpenCloseLock.release();
        }
    }

    /**
     * Starts a background thread and its {@link Handler}.
     */
    private void startBackgroundThread() {
        mBackgroundThread = new HandlerThread("CameraBackground");
        mBackgroundThread.start();
        mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
    }

    /**
     * Stops the background thread and its {@link Handler}.
     */
    private void stopBackgroundThread() {
        mBackgroundThread.quitSafely();
        try {
            mBackgroundThread.join();
            mBackgroundThread = null;
            mBackgroundHandler = null;
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    /**
     * Creates a new {@link CameraCaptureSession} for camera preview.
     */
    private void createCameraPreviewSession() {
        try {
            SurfaceTexture texture = mTextureView.getSurfaceTexture();
            assert texture != null;

            // We configure the size of default buffer to be the size of camera preview we want.
            texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());

            // This is the output Surface we need to start preview.
            Surface surface = new Surface(texture);

            // We set up a CaptureRequest.Builder with the output Surface.
            mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            mPreviewRequestBuilder.addTarget(surface);

            // Here, we create a CameraCaptureSession for camera preview.
            mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
                    new CameraCaptureSession.StateCallback() {

                        @Override
                        public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                            // The camera is already closed
                            if (null == mCameraDevice) {
                                return;
                            }

                            // When the session is ready, we start displaying the preview.
                            mCaptureSession = cameraCaptureSession;
                            try {
                                // Auto focus should be continuous for camera preview.
                                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
                                        CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
                                // Flash is automatically enabled when necessary.
                                setAutoFlash(mPreviewRequestBuilder);

                                // Finally, we start displaying the camera preview.
                                mPreviewRequest = mPreviewRequestBuilder.build();
                                mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback,
                                        mBackgroundHandler);
                            } catch (CameraAccessException e) {
                                e.printStackTrace();
                            }
                        }

                        @Override
                        public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                            showToast("Failed");
                        }
                    }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Configures the necessary {@link Matrix} transformation to `mTextureView`.
     * This method should be called after the camera preview size is determined in
     * setUpCameraOutputs and also the size of `mTextureView` is fixed.
     *
     * @param viewWidth  The width of `mTextureView`
     * @param viewHeight The height of `mTextureView`
     */
    private void configureTransform(int viewWidth, int viewHeight) {
        Activity activity = getActivity();
        if (null == mTextureView || null == mPreviewSize || null == activity) {
            return;
        }
        int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
        Matrix matrix = new Matrix();
        RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
        RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
        float centerX = viewRect.centerX();
        float centerY = viewRect.centerY();

        if (Surface.ROTATION_0 == rotation) {
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
            float scale = (float) (viewWidth / mPreviewSize.getWidth() + 0.6);
            matrix.postScale(scale, scale, centerX, centerY);
        }

        mTextureView.setTransform(matrix);
    }

    /**
     * Initiate a still image capture.
     */
    private void takePicture() {
        lockFocus();
    }

    /**
     * Lock the focus as the first step for a still image capture.
     */
    private void lockFocus() {
        try {
            // This is how to tell the camera to lock focus.
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
            // Tell #mCaptureCallback to wait for the lock.
            mState = STATE_WAITING_LOCK;
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Run the precapture sequence for capturing a still image. This method should be called when
     * we get a response in {@link #mCaptureCallback} from {@link #lockFocus()}.
     */
    private void runPrecaptureSequence() {
        try {
            // This is how to tell the camera to trigger.
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
                    CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
            // Tell #mCaptureCallback to wait for the precapture sequence to be set.
            mState = STATE_WAITING_PRECAPTURE;
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Capture a still picture. This method should be called when we get a response in
     * {@link #mCaptureCallback} from both {@link #lockFocus()}.
     */
    private void captureStillPicture() {
        try {
            final Activity activity = getActivity();
            if (null == activity || null == mCameraDevice) {
                return;
            }
            // This is the CaptureRequest.Builder that we use to take a picture.
            final CaptureRequest.Builder captureBuilder = mCameraDevice
                    .createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
            captureBuilder.addTarget(mImageReader.getSurface());

            // Use the same AE and AF modes as the preview.
            captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
            setAutoFlash(captureBuilder);

            // Orientation
            int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
            captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));

            CameraCaptureSession.CaptureCallback CaptureCallback = new CameraCaptureSession.CaptureCallback() {

                @Override
                public void onCaptureCompleted(@NonNull CameraCaptureSession session,
                        @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {

                    //                    showToast("Saved: " + mFile);
                    // Send broadcast message
                    final Activity activity = getActivity();
                    if (activity != null) {
                        activity.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                getActivity().sendBroadcast(new Intent(MainActivity.PHOTO_READY));
                            }
                        });
                    }

                    Log.i(TAG, "File path: " + mFile.toString());
                    unlockFocus();
                }
            };

            mCaptureSession.stopRepeating();
            mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Unlock the focus. This method should be called when still image capture sequence is
     * finished.
     */
    private void unlockFocus() {
        try {
            // Reset the auto-focus trigger
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
            setAutoFlash(mPreviewRequestBuilder);
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
            // After this, the camera will go back to the normal state of preview.
            mState = STATE_PREVIEW;
            mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback, mBackgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
        case R.id.picture: {
            takePicture();
            break;
        }
        }
    }

    private void setAutoFlash(CaptureRequest.Builder requestBuilder) {
        if (mFlashSupported) {
            requestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
        }
    }

    /**
     * Saves a JPEG {@link Image} into the specified {@link File}.
     */
    private static class ImageSaver implements Runnable {

        /**
         * The JPEG image
         */
        private final Image mImage;
        /**
         * The file we save the image into.
         */
        private final File mFile;

        public ImageSaver(Image image, File file) {
            mImage = image;
            mFile = file;
        }

        @Override
        public void run() {
            ByteBuffer buffer = mImage.getPlanes()[0].getBuffer();
            byte[] bytes = new byte[buffer.remaining()];
            buffer.get(bytes);
            FileOutputStream output = null;
            try {
                output = new FileOutputStream(mFile);
                output.write(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                mImage.close();
                if (null != output) {
                    try {
                        output.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

    }

    /**
     * Compares two {@code Size}s based on their areas.
     */
    static class CompareSizesByArea implements Comparator<Size> {

        @Override
        public int compare(Size lhs, Size rhs) {
            // We cast here to ensure the multiplications won't overflow
            return Long.signum((long) lhs.getWidth() * lhs.getHeight() - (long) rhs.getWidth() * rhs.getHeight());
        }

    }

    /**
     * Shows an error message dialog.
     */
    public static class ErrorDialog extends DialogFragment {

        private static final String ARG_MESSAGE = "message";

        public static ErrorDialog newInstance(String message) {
            ErrorDialog dialog = new ErrorDialog();
            Bundle args = new Bundle();
            args.putString(ARG_MESSAGE, message);
            dialog.setArguments(args);
            return dialog;
        }

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Activity activity = getActivity();
            return new AlertDialog.Builder(activity).setMessage(getArguments().getString(ARG_MESSAGE))
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            activity.finish();
                        }
                    }).create();
        }

    }

    /**
     * Shows OK/Cancel confirmation dialog about camera permission.
     */
    public static class ConfirmationDialog extends DialogFragment {

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Fragment parent = getParentFragment();
            return new AlertDialog.Builder(getActivity()).setMessage("This sample needs camera permission.")
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            FragmentCompat.requestPermissions(parent, new String[] { Manifest.permission.CAMERA },
                                    REQUEST_CAMERA_PERMISSION);
                        }
                    }).setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Activity activity = parent.getActivity();
                            if (activity != null) {
                                activity.finish();
                            }
                        }
                    }).create();
        }
    }

    public void showTakenPhoto(Bitmap bitmap) {
        photoView.setImageBitmap(bitmap);
        photoView.setVisibility(View.VISIBLE);
        progressInfoView.setVisibility(View.VISIBLE);
    }

    public void deactivateWhileProcessingImage() {
        takePictureButton.setVisibility(View.INVISIBLE);
    }

    public void activateAfterProcessingImage() {
        takePictureButton.setVisibility(View.VISIBLE);
        photoView.setVisibility(View.INVISIBLE);
        progressInfoView.setVisibility(View.INVISIBLE);
    }

}