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Camera2Basic / src / com.example.android.camera2basic /

Camera2BasicFragment.java

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/*
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 * Copyright 2014 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *       http://www.apache.org/licenses/LICENSE-2.0
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 *
10
 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
16
 
17
package com.example.android.camera2basic;
18
 
19
import android.app.Activity;
20
import android.app.AlertDialog;
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import android.app.Dialog;
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import android.app.DialogFragment;
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import android.app.Fragment;
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import android.content.Context;
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import android.content.DialogInterface;
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import android.content.res.Configuration;
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import android.graphics.ImageFormat;
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import android.graphics.Matrix;
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import android.graphics.RectF;
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import android.graphics.SurfaceTexture;
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import android.hardware.camera2.CameraAccessException;
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import android.hardware.camera2.CameraCaptureSession;
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import android.hardware.camera2.CameraCharacteristics;
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import android.hardware.camera2.CameraDevice;
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import android.hardware.camera2.CameraManager;
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import android.hardware.camera2.CameraMetadata;
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import android.hardware.camera2.CaptureRequest;
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import android.hardware.camera2.CaptureResult;
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import android.hardware.camera2.TotalCaptureResult;
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import android.hardware.camera2.params.StreamConfigurationMap;
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import android.media.Image;
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import android.media.ImageReader;
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import android.os.Bundle;
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import android.os.Handler;
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import android.os.HandlerThread;
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import android.util.Log;
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import android.util.Size;
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import android.util.SparseIntArray;
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import android.view.LayoutInflater;
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import android.view.Surface;
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import android.view.TextureView;
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import android.view.View;
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import android.view.ViewGroup;
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import android.widget.Toast;
55
 
56
import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collections;
64
import java.util.Comparator;
65
import java.util.List;
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import java.util.concurrent.Semaphore;
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import java.util.concurrent.TimeUnit;
68
 
69
public class Camera2BasicFragment extends Fragment implements View.OnClickListener {
70
 
71
    /**
72
     * Conversion from screen rotation to JPEG orientation.
73
     */
74
    private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
75
 
76
    static {
77
        ORIENTATIONS.append(Surface.ROTATION_0, 90);
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        ORIENTATIONS.append(Surface.ROTATION_90, 0);
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        ORIENTATIONS.append(Surface.ROTATION_180, 270);
80
        ORIENTATIONS.append(Surface.ROTATION_270, 180);
81
    }
82
 
83
    /**
84
     * Tag for the {@link Log}.
85
     */
86
    private static final String TAG = "Camera2BasicFragment";
87
 
88
    /**
89
     * Camera state: Showing camera preview.
90
     */
91
    private static final int STATE_PREVIEW = 0;
92
 
93
    /**
94
     * Camera state: Waiting for the focus to be locked.
95
     */
96
    private static final int STATE_WAITING_LOCK = 1;
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    /**
98
     * Camera state: Waiting for the exposure to be precapture state.
99
     */
100
    private static final int STATE_WAITING_PRECAPTURE = 2;
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    /**
102
     * Camera state: Waiting for the exposure state to be something other than precapture.
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     */
104
    private static final int STATE_WAITING_NON_PRECAPTURE = 3;
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    /**
106
     * Camera state: Picture was taken.
107
     */
108
    private static final int STATE_PICTURE_TAKEN = 4;
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110
    /**
111
     * {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a
112
     * {@link TextureView}.
113
     */
114
    private final TextureView.SurfaceTextureListener mSurfaceTextureListener
115
            = new TextureView.SurfaceTextureListener() {
116
 
117
        @Override
118
        public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) {
119
            openCamera(width, height);
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        }
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122
        @Override
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        public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) {
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            configureTransform(width, height);
125
        }
126
 
127
        @Override
128
        public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) {
129
            return true;
130
        }
131
 
132
        @Override
133
        public void onSurfaceTextureUpdated(SurfaceTexture texture) {
134
        }
135
 
136
    };
137
 
138
    /**
139
     * ID of the current {@link CameraDevice}.
140
     */
141
    private String mCameraId;
142
 
143
    /**
144
     * An {@link AutoFitTextureView} for camera preview.
145
     */
146
    private AutoFitTextureView mTextureView;
147
 
148
    /**
149
     * A {@link CameraCaptureSession } for camera preview.
150
     */
151
 
152
    private CameraCaptureSession mCaptureSession;
153
    /**
154
     * A reference to the opened {@link CameraDevice}.
155
     */
156
 
157
    private CameraDevice mCameraDevice;
158
    /**
159
     * The {@link android.util.Size} of camera preview.
160
     */
161
 
162
    private Size mPreviewSize;
163
 
164
    /**
165
     * {@link CameraDevice.StateCallback} is called when {@link CameraDevice} changes its state.
166
     */
167
    private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
168
 
169
        @Override
170
        public void onOpened(CameraDevice cameraDevice) {
171
            // This method is called when the camera is opened.  We start camera preview here.
172
            mCameraOpenCloseLock.release();
173
            mCameraDevice = cameraDevice;
174
            createCameraPreviewSession();
175
        }
176
 
177
        @Override
178
        public void onDisconnected(CameraDevice cameraDevice) {
179
            mCameraOpenCloseLock.release();
180
            cameraDevice.close();
181
            mCameraDevice = null;
182
        }
183
 
184
        @Override
185
        public void onError(CameraDevice cameraDevice, int error) {
186
            mCameraOpenCloseLock.release();
187
            cameraDevice.close();
188
            mCameraDevice = null;
189
            Activity activity = getActivity();
190
            if (null != activity) {
191
                activity.finish();
192
            }
193
        }
194
 
195
    };
196
 
197
    /**
198
     * An additional thread for running tasks that shouldn't block the UI.
199
     */
200
    private HandlerThread mBackgroundThread;
201
 
202
    /**
203
     * A {@link Handler} for running tasks in the background.
204
     */
205
    private Handler mBackgroundHandler;
206
 
207
    /**
208
     * An {@link ImageReader} that handles still image capture.
209
     */
210
    private ImageReader mImageReader;
211
 
212
    /**
213
     * This is the output file for our picture.
214
     */
215
    private File mFile;
216
 
217
    /**
218
     * This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a
219
     * still image is ready to be saved.
220
     */
221
    private final ImageReader.OnImageAvailableListener mOnImageAvailableListener
222
            = new ImageReader.OnImageAvailableListener() {
223
 
224
        @Override
225
        public void onImageAvailable(ImageReader reader) {
226
            mBackgroundHandler.post(new ImageSaver(reader.acquireNextImage(), mFile));
227
        }
228
 
229
    };
230
 
231
    /**
232
     * {@link CaptureRequest.Builder} for the camera preview
233
     */
234
    private CaptureRequest.Builder mPreviewRequestBuilder;
235
 
236
    /**
237
     * {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder}
238
     */
239
    private CaptureRequest mPreviewRequest;
240
 
241
    /**
242
     * The current state of camera state for taking pictures.
243
     *
244
     * @see #mCaptureCallback
245
     */
246
    private int mState = STATE_PREVIEW;
247
 
248
    /**
249
     * A {@link Semaphore} to prevent the app from exiting before closing the camera.
250
     */
251
    private Semaphore mCameraOpenCloseLock = new Semaphore(1);
252
 
253
    /**
254
     * A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture.
255
     */
256
    private CameraCaptureSession.CaptureCallback mCaptureCallback
257
            = new CameraCaptureSession.CaptureCallback() {
258
 
259
        private void process(CaptureResult result) {
260
            switch (mState) {
261
                case STATE_PREVIEW: {
262
                    // We have nothing to do when the camera preview is working normally.
263
                    break;
264
                }
265
                case STATE_WAITING_LOCK: {
266
                    int afState = result.get(CaptureResult.CONTROL_AF_STATE);
267
                    if (CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED == afState ||
268
                            CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED == afState) {
269
                        // CONTROL_AE_STATE can be null on some devices
270
                        Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
271
                        if (aeState == null ||
272
                                aeState == CaptureResult.CONTROL_AE_STATE_CONVERGED) {
273
                            mState = STATE_WAITING_NON_PRECAPTURE;
274
                            captureStillPicture();
275
                        } else {
276
                            runPrecaptureSequence();
277
                        }
278
                    }
279
                    break;
280
                }
281
                case STATE_WAITING_PRECAPTURE: {
282
                    // CONTROL_AE_STATE can be null on some devices
283
                    Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
284
                    if (aeState == null ||
285
                            aeState == CaptureResult.CONTROL_AE_STATE_PRECAPTURE ||
286
                            aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED) {
287
                        mState = STATE_WAITING_NON_PRECAPTURE;
288
                    }
289
                    break;
290
                }
291
                case STATE_WAITING_NON_PRECAPTURE: {
292
                    // CONTROL_AE_STATE can be null on some devices
293
                    Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
294
                    if (aeState == null || aeState != CaptureResult.CONTROL_AE_STATE_PRECAPTURE) {
295
                        mState = STATE_PICTURE_TAKEN;
296
                        captureStillPicture();
297
                    }
298
                    break;
299
                }
300
            }
301
        }
302
 
303
        @Override
304
        public void onCaptureProgressed(CameraCaptureSession session, CaptureRequest request,
305
                                        CaptureResult partialResult) {
306
            process(partialResult);
307
        }
308
 
309
        @Override
310
        public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
311
                                       TotalCaptureResult result) {
312
            process(result);
313
        }
314
 
315
    };
316
 
317
    /**
318
     * Given {@code choices} of {@code Size}s supported by a camera, chooses the smallest one whose
319
     * width and height are at least as large as the respective requested values, and whose aspect
320
     * ratio matches with the specified value.
321
     *
322
     * @param choices     The list of sizes that the camera supports for the intended output class
323
     * @param width       The minimum desired width
324
     * @param height      The minimum desired height
325
     * @param aspectRatio The aspect ratio
326
     * @return The optimal {@code Size}, or an arbitrary one if none were big enough
327
     */
328
    private static Size chooseOptimalSize(Size[] choices, int width, int height, Size aspectRatio) {
329
        // Collect the supported resolutions that are at least as big as the preview Surface
330
        List<Size> bigEnough = new ArrayList<Size>();
331
        int w = aspectRatio.getWidth();
332
        int h = aspectRatio.getHeight();
333
        for (Size option : choices) {
334
            if (option.getHeight() == option.getWidth() * h / w &&
335
                    option.getWidth() >= width && option.getHeight() >= height) {
336
                bigEnough.add(option);
337
            }
338
        }
339
 
340
        // Pick the smallest of those, assuming we found any
341
        if (bigEnough.size() > 0) {
342
            return Collections.min(bigEnough, new CompareSizesByArea());
343
        } else {
344
            Log.e(TAG, "Couldn't find any suitable preview size");
345
            return choices[0];
346
        }
347
    }
348
 
349
    public static Camera2BasicFragment newInstance() {
350
        Camera2BasicFragment fragment = new Camera2BasicFragment();
351
        fragment.setRetainInstance(true);
352
        return fragment;
353
    }
354
 
355
    @Override
356
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
357
                             Bundle savedInstanceState) {
358
        return inflater.inflate(R.layout.fragment_camera2_basic, container, false);
359
    }
360
 
361
    @Override
362
    public void onViewCreated(final View view, Bundle savedInstanceState) {
363
        view.findViewById(R.id.picture).setOnClickListener(this);
364
        view.findViewById(R.id.info).setOnClickListener(this);
365
        mTextureView = (AutoFitTextureView) view.findViewById(R.id.texture);
366
    }
367
 
368
    @Override
369
    public void onActivityCreated(Bundle savedInstanceState) {
370
        super.onActivityCreated(savedInstanceState);
371
        mFile = new File(getActivity().getExternalFilesDir(null), "pic.jpg");
372
    }
373
 
374
    @Override
375
    public void onResume() {
376
        super.onResume();
377
        startBackgroundThread();
378
 
379
        // When the screen is turned off and turned back on, the SurfaceTexture is already
380
        // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
381
        // a camera and start preview from here (otherwise, we wait until the surface is ready in
382
        // the SurfaceTextureListener).
383
        if (mTextureView.isAvailable()) {
384
            openCamera(mTextureView.getWidth(), mTextureView.getHeight());
385
        } else {
386
            mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
387
        }
388
    }
389
 
390
    @Override
391
    public void onPause() {
392
        closeCamera();
393
        stopBackgroundThread();
394
        super.onPause();
395
    }
396
 
397
    /**
398
     * Sets up member variables related to camera.
399
     *
400
     * @param width  The width of available size for camera preview
401
     * @param height The height of available size for camera preview
402
     */
403
    private void setUpCameraOutputs(int width, int height) {
404
        Activity activity = getActivity();
405
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
406
        try {
407
            for (String cameraId : manager.getCameraIdList()) {
408
                CameraCharacteristics characteristics
409
                        = manager.getCameraCharacteristics(cameraId);
410
 
411
                // We don't use a front facing camera in this sample.
412
                if (characteristics.get(CameraCharacteristics.LENS_FACING)
413
                        == CameraCharacteristics.LENS_FACING_FRONT) {
414
                    continue;
415
                }
416
 
417
                StreamConfigurationMap map = characteristics.get(
418
                        CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
419
 
420
                // For still image captures, we use the largest available size.
421
                Size largest = Collections.max(
422
                        Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)),
423
                        new CompareSizesByArea());
424
                mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(),
425
                        ImageFormat.JPEG, /*maxImages*/2);
426
                mImageReader.setOnImageAvailableListener(
427
                        mOnImageAvailableListener, mBackgroundHandler);
428
 
429
                // Danger, W.R.! Attempting to use too large a preview size could  exceed the camera
430
                // bus' bandwidth limitation, resulting in gorgeous previews but the storage of
431
                // garbage capture data.
432
                mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class),
433
                        width, height, largest);
434
 
435
                // We fit the aspect ratio of TextureView to the size of preview we picked.
436
                int orientation = getResources().getConfiguration().orientation;
437
                if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
438
                    mTextureView.setAspectRatio(
439
                            mPreviewSize.getWidth(), mPreviewSize.getHeight());
440
                } else {
441
                    mTextureView.setAspectRatio(
442
                            mPreviewSize.getHeight(), mPreviewSize.getWidth());
443
                }
444
 
445
                mCameraId = cameraId;
446
                return;
447
            }
448
        } catch (CameraAccessException e) {
449
            e.printStackTrace();
450
        } catch (NullPointerException e) {
451
            // Currently an NPE is thrown when the Camera2API is used but not supported on the
452
            // device this code runs.
453
            new ErrorDialog().show(getFragmentManager(), "dialog");
454
        }
455
    }
456
 
457
    /**
458
     * Opens the camera specified by {@link Camera2BasicFragment#mCameraId}.
459
     */
460
    private void openCamera(int width, int height) {
461
        setUpCameraOutputs(width, height);
462
        configureTransform(width, height);
463
        Activity activity = getActivity();
464
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
465
        try {
466
            if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
467
                throw new RuntimeException("Time out waiting to lock camera opening.");
468
            }
469
            manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
470
        } catch (CameraAccessException e) {
471
            e.printStackTrace();
472
        } catch (InterruptedException e) {
473
            throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
474
        }
475
    }
476
 
477
    /**
478
     * Closes the current {@link CameraDevice}.
479
     */
480
    private void closeCamera() {
481
        try {
482
            mCameraOpenCloseLock.acquire();
483
            if (null != mCaptureSession) {
484
                mCaptureSession.close();
485
                mCaptureSession = null;
486
            }
487
            if (null != mCameraDevice) {
488
                mCameraDevice.close();
489
                mCameraDevice = null;
490
            }
491
            if (null != mImageReader) {
492
                mImageReader.close();
493
                mImageReader = null;
494
            }
495
        } catch (InterruptedException e) {
496
            throw new RuntimeException("Interrupted while trying to lock camera closing.", e);
497
        } finally {
498
            mCameraOpenCloseLock.release();
499
        }
500
    }
501
 
502
    /**
503
     * Starts a background thread and its {@link Handler}.
504
     */
505
    private void startBackgroundThread() {
506
        mBackgroundThread = new HandlerThread("CameraBackground");
507
        mBackgroundThread.start();
508
        mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
509
    }
510
 
511
    /**
512
     * Stops the background thread and its {@link Handler}.
513
     */
514
    private void stopBackgroundThread() {
515
        mBackgroundThread.quitSafely();
516
        try {
517
            mBackgroundThread.join();
518
            mBackgroundThread = null;
519
            mBackgroundHandler = null;
520
        } catch (InterruptedException e) {
521
            e.printStackTrace();
522
        }
523
    }
524
 
525
    /**
526
     * Creates a new {@link CameraCaptureSession} for camera preview.
527
     */
528
    private void createCameraPreviewSession() {
529
        try {
530
            SurfaceTexture texture = mTextureView.getSurfaceTexture();
531
            assert texture != null;
532
 
533
            // We configure the size of default buffer to be the size of camera preview we want.
534
            texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
535
 
536
            // This is the output Surface we need to start preview.
537
            Surface surface = new Surface(texture);
538
 
539
            // We set up a CaptureRequest.Builder with the output Surface.
540
            mPreviewRequestBuilder
541
                    = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
542
            mPreviewRequestBuilder.addTarget(surface);
543
 
544
            // Here, we create a CameraCaptureSession for camera preview.
545
            mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()),
546
                    new CameraCaptureSession.StateCallback() {
547
 
548
                        @Override
549
                        public void onConfigured(CameraCaptureSession cameraCaptureSession) {
550
                            // The camera is already closed
551
                            if (null == mCameraDevice) {
552
                                return;
553
                            }
554
 
555
                            // When the session is ready, we start displaying the preview.
556
                            mCaptureSession = cameraCaptureSession;
557
                            try {
558
                                // Auto focus should be continuous for camera preview.
559
                                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE,
560
                                        CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
561
                                // Flash is automatically enabled when necessary.
562
                                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
563
                                        CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
564
 
565
                                // Finally, we start displaying the camera preview.
566
                                mPreviewRequest = mPreviewRequestBuilder.build();
567
                                mCaptureSession.setRepeatingRequest(mPreviewRequest,
568
                                        mCaptureCallback, mBackgroundHandler);
569
                            } catch (CameraAccessException e) {
570
                                e.printStackTrace();
571
                            }
572
                        }
573
 
574
                        @Override
575
                        public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
576
                            Activity activity = getActivity();
577
                            if (null != activity) {
578
                                Toast.makeText(activity, "Failed", Toast.LENGTH_SHORT).show();
579
                            }
580
                        }
581
                    }, null
582
            );
583
        } catch (CameraAccessException e) {
584
            e.printStackTrace();
585
        }
586
    }
587
 
588
    /**
589
     * Configures the necessary {@link android.graphics.Matrix} transformation to `mTextureView`.
590
     * This method should be called after the camera preview size is determined in
591
     * setUpCameraOutputs and also the size of `mTextureView` is fixed.
592
     *
593
     * @param viewWidth  The width of `mTextureView`
594
     * @param viewHeight The height of `mTextureView`
595
     */
596
    private void configureTransform(int viewWidth, int viewHeight) {
597
        Activity activity = getActivity();
598
        if (null == mTextureView || null == mPreviewSize || null == activity) {
599
            return;
600
        }
601
        int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
602
        Matrix matrix = new Matrix();
603
        RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
604
        RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
605
        float centerX = viewRect.centerX();
606
        float centerY = viewRect.centerY();
607
        if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
608
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
609
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
610
            float scale = Math.max(
611
                    (float) viewHeight / mPreviewSize.getHeight(),
612
                    (float) viewWidth / mPreviewSize.getWidth());
613
            matrix.postScale(scale, scale, centerX, centerY);
614
            matrix.postRotate(90 * (rotation - 2), centerX, centerY);
615
        }
616
        mTextureView.setTransform(matrix);
617
    }
618
 
619
    /**
620
     * Initiate a still image capture.
621
     */
622
    private void takePicture() {
623
        lockFocus();
624
    }
625
 
626
    /**
627
     * Lock the focus as the first step for a still image capture.
628
     */
629
    private void lockFocus() {
630
        try {
631
            // This is how to tell the camera to lock focus.
632
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
633
                    CameraMetadata.CONTROL_AF_TRIGGER_START);
634
            // Tell #mCaptureCallback to wait for the lock.
635
            mState = STATE_WAITING_LOCK;
636
            mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), mCaptureCallback,
637
                    mBackgroundHandler);
638
        } catch (CameraAccessException e) {
639
            e.printStackTrace();
640
        }
641
    }
642
 
643
    /**
644
     * Run the precapture sequence for capturing a still image. This method should be called when we
645
     * get a response in {@link #mCaptureCallback} from {@link #lockFocus()}.
646
     */
647
    private void runPrecaptureSequence() {
648
        try {
649
            // This is how to tell the camera to trigger.
650
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER,
651
                    CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER_START);
652
            // Tell #mCaptureCallback to wait for the precapture sequence to be set.
653
            mState = STATE_WAITING_PRECAPTURE;
654
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
655
                    mBackgroundHandler);
656
        } catch (CameraAccessException e) {
657
            e.printStackTrace();
658
        }
659
    }
660
 
661
    /**
662
     * Capture a still picture. This method should be called when we get a response in
663
     * {@link #mCaptureCallback} from both {@link #lockFocus()}.
664
     */
665
    private void captureStillPicture() {
666
        try {
667
            final Activity activity = getActivity();
668
            if (null == activity || null == mCameraDevice) {
669
                return;
670
            }
671
            // This is the CaptureRequest.Builder that we use to take a picture.
672
            final CaptureRequest.Builder captureBuilder =
673
                    mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
674
            captureBuilder.addTarget(mImageReader.getSurface());
675
 
676
            // Use the same AE and AF modes as the preview.
677
            captureBuilder.set(CaptureRequest.CONTROL_AF_MODE,
678
                    CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
679
            captureBuilder.set(CaptureRequest.CONTROL_AE_MODE,
680
                    CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
681
 
682
            // Orientation
683
            int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
684
            captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
685
 
686
            CameraCaptureSession.CaptureCallback CaptureCallback
687
                    = new CameraCaptureSession.CaptureCallback() {
688
 
689
                @Override
690
                public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request,
691
                                               TotalCaptureResult result) {
692
                    Toast.makeText(getActivity(), "Saved: " + mFile, Toast.LENGTH_SHORT).show();
693
                    unlockFocus();
694
                }
695
            };
696
 
697
            mCaptureSession.stopRepeating();
698
            mCaptureSession.capture(captureBuilder.build(), CaptureCallback, null);
699
        } catch (CameraAccessException e) {
700
            e.printStackTrace();
701
        }
702
    }
703
 
704
    /**
705
     * Unlock the focus. This method should be called when still image capture sequence is finished.
706
     */
707
    private void unlockFocus() {
708
        try {
709
            // Reset the autofucos trigger
710
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER,
711
                    CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
712
            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE,
713
                    CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
714
            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback,
715
                    mBackgroundHandler);
716
            // After this, the camera will go back to the normal state of preview.
717
            mState = STATE_PREVIEW;
718
            mCaptureSession.setRepeatingRequest(mPreviewRequest, mCaptureCallback,
719
                    mBackgroundHandler);
720
        } catch (CameraAccessException e) {
721
            e.printStackTrace();
722
        }
723
    }
724
 
725
    @Override
726
    public void onClick(View view) {
727
        switch (view.getId()) {
728
            case R.id.picture: {
729
                takePicture();
730
                break;
731
            }
732
            case R.id.info: {
733
                Activity activity = getActivity();
734
                if (null != activity) {
735
                    new AlertDialog.Builder(activity)
736
                            .setMessage(R.string.intro_message)
737
                            .setPositiveButton(android.R.string.ok, null)
738
                            .show();
739
                }
740
                break;
741
            }
742
        }
743
    }
744
 
745
    /**
746
     * Saves a JPEG {@link Image} into the specified {@link File}.
747
     */
748
    private static class ImageSaver implements Runnable {
749
 
750
        /**
751
         * The JPEG image
752
         */
753
        private final Image mImage;
754
        /**
755
         * The file we save the image into.
756
         */
757
        private final File mFile;
758
 
759
        public ImageSaver(Image image, File file) {
760
            mImage = image;
761
            mFile = file;
762
        }
763
 
764
        @Override
765
        public void run() {
766
            ByteBuffer buffer = mImage.getPlanes()[0].getBuffer();
767
            byte[] bytes = new byte[buffer.remaining()];
768
            buffer.get(bytes);
769
            FileOutputStream output = null;
770
            try {
771
                output = new FileOutputStream(mFile);
772
                output.write(bytes);
773
            } catch (FileNotFoundException e) {
774
                e.printStackTrace();
775
            } catch (IOException e) {
776
                e.printStackTrace();
777
            } finally {
778
                mImage.close();
779
                if (null != output) {
780
                    try {
781
                        output.close();
782
                    } catch (IOException e) {
783
                        e.printStackTrace();
784
                    }
785
                }
786
            }
787
        }
788
 
789
    }
790
 
791
    /**
792
     * Compares two {@code Size}s based on their areas.
793
     */
794
    static class CompareSizesByArea implements Comparator<Size> {
795
 
796
        @Override
797
        public int compare(Size lhs, Size rhs) {
798
            // We cast here to ensure the multiplications won't overflow
799
            return Long.signum((long) lhs.getWidth() * lhs.getHeight() -
800
                    (long) rhs.getWidth() * rhs.getHeight());
801
        }
802
 
803
    }
804
 
805
    public static class ErrorDialog extends DialogFragment {
806
 
807
        @Override
808
        public Dialog onCreateDialog(Bundle savedInstanceState) {
809
            final Activity activity = getActivity();
810
            return new AlertDialog.Builder(activity)
811
                    .setMessage("This device doesn't support Camera2 API.")
812
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
813
                        @Override
814
                        public void onClick(DialogInterface dialogInterface, int i) {
815
                            activity.finish();
816