cliq.com.cliqgram.fragments.CameraFragment.java Source code

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Here is the source code for cliq.com.cliqgram.fragments.CameraFragment.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 cliq.com.cliqgram.fragments;

import android.Manifest;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
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.ImageReader;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.v13.app.FragmentCompat;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
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.Button;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;
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;

import butterknife.Bind;
import butterknife.ButterKnife;
import cliq.com.cliqgram.R;
import cliq.com.cliqgram.activities.ImageDisplayActivity;
import cliq.com.cliqgram.callbacks.ImageSavedCallback;
import cliq.com.cliqgram.utils.ImageSaver;
import cliq.com.cliqgram.utils.ImageUtil;
import cliq.com.cliqgram.utils.PermissionUtil;
import cliq.com.cliqgram.utils.Utils;
import cliq.com.cliqgram.views.AutoFitTextureView;

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class CameraFragment extends Fragment
        implements View.OnClickListener, FragmentCompat.OnRequestPermissionsResultCallback {

    /**
     * Conversion from screen rotation to JPEG orientation.
     */
    private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
    private static final int REQUEST_CAMERA_PERMISSION = 1;
    private static final String FRAGMENT_DIALOG = "dialog";

    private static final int PICK_IMAGE_REQUEST = 1;

    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);
    }

    /**
     * Tag for the {@link Log}.
     */
    private static final String TAG = "Camera2BasicFragment";

    /**
     * Camera state: Showing camera preview.
     */
    private static final int STATE_PREVIEW = 0;

    /**
     * Camera state: Waiting for the focus to be locked.
     */
    private static final int STATE_WAITING_LOCK = 1;

    /**
     * Camera state: Waiting for the exposure to be precapture state.
     */
    private static final int STATE_WAITING_PRECAPTURE = 2;

    /**
     * Camera state: Waiting for the exposure state to be something other than precapture.
     */
    private static final int STATE_WAITING_NON_PRECAPTURE = 3;

    /**
     * Camera state: Picture was taken.
     */
    private static final int STATE_PICTURE_TAKEN = 4;

    /**
     * {@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) {
        }

    };

    /**
     * ID of the current {@link CameraDevice}.
     */
    private String mCameraId;

    /**
     * An {@link AutoFitTextureView} for camera preview.
     */
    @Bind(R.id.textureView_preview)
    AutoFitTextureView mTextureView;

    /**
     * An {@link View} for grid view.
     */
    @Bind(R.id.view_grid)
    View myGridView;

    /**
     *
     */
    @Bind(R.id.button_capture)
    FloatingActionButton buttonCapture;

    /**
     *
     */
    @Bind(R.id.button_flash)
    Button buttonFlash;

    /**
     *
     */
    @Bind(R.id.button_grid)
    Button buttonGrid;

    /**
     *
     */
    @Bind(R.id.button_gallery)
    Button buttonGallery;
    //    private boolean imageSaved = false;
    private boolean flashOn = true;
    private boolean gridOn = false;

    /**
     * A {@link CameraCaptureSession } for camera preview.
     */
    private CameraCaptureSession mCaptureSession;

    /**
     * A reference to the opened {@link CameraDevice}.
     */
    private CameraDevice mCameraDevice;

    /**
     * The {@link Size} of camera preview.
     */
    private Size mPreviewSize;

    /**
     * {@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();
            }
        }

    };

    /**
     * An additional thread for running tasks that shouldn't block the UI.
     */
    private HandlerThread mBackgroundThread;

    /**
     * A {@link Handler} for running tasks in the background.
     */
    private Handler mBackgroundHandler;

    /**
     * An {@link ImageReader} that handles still image capture.
     */
    private ImageReader mImageReader;

    /**
     * This is the output file for our picture.
     */
    private File mFile;

    /**
     * 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(getActivity(), reader.acquireNextImage(), mFile, null));
        }

    };

    /**
     * {@link CaptureRequest.Builder} for the camera preview
     */
    private CaptureRequest.Builder mPreviewRequestBuilder;

    /**
     * {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder}
     */
    private CaptureRequest mPreviewRequest;

    /**
     * The current state of camera state for taking pictures.
     *
     * @see #mCaptureCallback
     */
    private int mState = STATE_PREVIEW;

    /**
     * A {@link Semaphore} to prevent the app from exiting before closing the camera.
     */
    private Semaphore mCameraOpenCloseLock = new Semaphore(1);

    /**
     * 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_LONG).show();
                }
            });
        }
    }

    /**
     * Given {@code choices} of {@code Size}s supported by a camera, chooses the smallest one whose
     * width and height are at least as large as the respective requested values, 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 width       The minimum desired width
     * @param height      The minimum desired height
     * @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 width, int height, Size aspectRatio) {
        // Collect the supported resolutions that are at least as big as the preview Surface
        List<Size> bigEnough = new ArrayList<>();
        int w = aspectRatio.getWidth();
        int h = aspectRatio.getHeight();
        for (Size option : choices) {
            if (option.getHeight() == option.getWidth() * h / w && option.getWidth() >= width
                    && option.getHeight() >= height) {
                bigEnough.add(option);
            }
        }

        // Pick the smallest of those, assuming we found any
        if (bigEnough.size() > 0) {
            return Collections.min(bigEnough, new CompareSizesByArea());
        } else {
            Log.e(TAG, "Couldn't find any suitable preview size");
            return choices[0];
        }
    }

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_camera2_basic, container, false);
    }

    @Override
    public void onViewCreated(final View view, Bundle savedInstanceState) {

        // bind view to ButterKnife
        ButterKnife.bind(this, view);

        /**
         * set click listener for buttons
         */
        buttonCapture.setOnClickListener(this);
        buttonFlash.setOnClickListener(this);
        buttonGallery.setOnClickListener(this);
        buttonGrid.setOnClickListener(this);
        //        mTextureView = (AutoFitTextureView) view.findViewById(R.id.texture);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        String picName = String.valueOf(Utils.getCurrentDate().getTime());
        mFile = new File(getActivity().getExternalFilesDir(null), picName + ".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() {

        PermissionUtil.requestPermission((AppCompatActivity) getActivity(),
                "The app requires camera permission to continue.", 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) {
                PermissionUtil.ErrorDialog.newInstance(getString(R.string.request_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);

                // 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), width, height, largest);

                // We fit the aspect ratio of TextureView to the size of preview we picked.
                int orientation = getResources().getConfiguration().orientation;
                if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
                    mTextureView.setAspectRatio(mPreviewSize.getWidth(), mPreviewSize.getHeight());
                } else {
                    mTextureView.setAspectRatio(mPreviewSize.getHeight(), mPreviewSize.getWidth());
                }

                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.
            PermissionUtil.ErrorDialog.newInstance(getString(R.string.camera_error)).show(getChildFragmentManager(),
                    FRAGMENT_DIALOG);
        }
    }

    /**
     * Opens the camera specified by {@link CameraFragment#mCameraId}.
     */
    private void openCamera(int width, int height) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (getActivity()
                    .checkSelfPermission(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.
                                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
                                        CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);

                                // 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_90 == rotation || Surface.ROTATION_270 == rotation) {
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
            float scale = Math.max((float) viewHeight / mPreviewSize.getHeight(),
                    (float) viewWidth / mPreviewSize.getWidth());
            matrix.postScale(scale, scale, centerX, centerY);
            matrix.postRotate(90 * (rotation - 2), centerX, centerY);
        } else if (Surface.ROTATION_180 == rotation) {
            matrix.postRotate(180, 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);
            captureBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);

            // check to turn on/off flash mode
            captureBuilder.set(CaptureRequest.FLASH_MODE,
                    flashOn ? CaptureResult.FLASH_MODE_SINGLE : CaptureResult.FLASH_MODE_OFF);

            // 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);
                    Log.d(TAG, "Saved file: " + mFile.toString());
                    unlockFocus();

                    startImageDisplayActivity(mFile.getName());

                }
            };

            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);
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
                    CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
            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.button_capture:
            takePicture();
            break;
        case R.id.button_flash:
            if (flashOn) {
                flashOn = false;
                ImageUtil.loadResToView(getActivity(), R.drawable.icon_flash_off, buttonFlash, 0.7f);
            } else {
                flashOn = true;
                ImageUtil.loadResToView(getActivity(), R.drawable.icon_flash_on, buttonFlash, 0.7f);
            }
            break;
        case R.id.button_grid:
            // TODO
            if (gridOn) {
                gridOn = false;
                myGridView.setVisibility(View.INVISIBLE);
                ImageUtil.loadResToView(getActivity(), R.drawable.icon_grid_off, buttonGrid, 0.7f);
            } else {
                gridOn = true;
                myGridView.setVisibility(View.VISIBLE);
                ImageUtil.loadResToView(getActivity(), R.drawable.icon_grid_on, buttonGrid, 0.7f);
            }
            break;
        case R.id.button_gallery:

            Intent intent = new Intent();
            // Show only images, no videos or anything else
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            // Always show the chooser (if there are multiple options available)
            startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST);

            break;
        }
    }

    /**
     * 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());
        }

    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        Activity activity = getActivity();

        if (requestCode == PICK_IMAGE_REQUEST && resultCode == Activity.RESULT_OK && data != null
                && data.getData() != null) {

            /**
             * @param imageDate byte[]
             * @param currentUser User
             * @param description String
             * @return post Post
             * Note: Any data in post object may not be able to
             * get before post.saveInBackground() in finished.
             * So, check the database (table "Post") on Parse to see if post is
             * created successfully.
             * If post is created successfully, it will be shown on home page.
             */
            Uri uri = data.getData();

            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(activity.getContentResolver(), uri);
                // Log.d(TAG, String.valueOf(bitmap));

                startImageDisplayActivity(bitmap);

            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            activity.finish();
        }
    }

    /**
     * open ImageDisplayActivity and pass recent taken/selected image to it
     *
     * @param bitmap
     */
    private void startImageDisplayActivity(Bitmap bitmap) {

        new ImageSaver(getActivity(), bitmap, mFile, new ImageSavedCallback() {
            @Override
            public void onImageSaved(String fileName) {
                startImageDisplayActivity(mFile.getName());
            }
        }).run();

    }

    private void startImageDisplayActivity(String fileName) {
        Intent intent = new Intent(getActivity(), ImageDisplayActivity.class);
        intent.putExtra("image", fileName);
        startActivity(intent);

        // finish current activity
        getActivity().finish();
    }

}