为什么推荐使用Jetpack CameraX？
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详情见文章：没错！皇叔开了个训练营
前言
Camera2
CameraX
private void setupCamera(PreviewView previewView) {
ListenableFuture<ProcessCameraProvider> cameraProviderFuture =
ProcessCameraProvider.getInstance(this);
cameraProviderFuture.addListener(() -> {
try {
mCameraProvider = cameraProviderFuture.get();
bindPreview(mCameraProvider, previewView);
} catch (ExecutionException | InterruptedException e) {
e.printStackTrace();
}
}, ContextCompat.getMainExecutor(this));
}
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider,
PreviewView previewView) {
mPreview = new Preview.Builder().build();
mCamera = cameraProvider.bindToLifecycle(this,
CameraSelector.DEFAULT_BACK_CAMERA, mPreview);
mPreview.setSurfaceProvider(previewView.getSurfaceProvider());
}
public void onChangeGo(View view) {
if (mCameraProvider != null) {
isBack = !isBack;
bindPreview(mCameraProvider, binding.previewView);
}
}
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider,
PreviewView previewView) {
...
CameraSelector cameraSelector = isBack ? CameraSelector.DEFAULT_BACK_CAMERA
: CameraSelector.DEFAULT_FRONT_CAMERA;
// 绑定前确保解除了所有绑定，防止CameraProvider重复绑定到Lifecycle发生异常
cameraProvider.unbindAll();
mCamera = cameraProvider.bindToLifecycle(this, cameraSelector, mPreview);
...
}
protected void onCreate(@Nullable Bundle savedInstanceState) {
...
binding.previewView.setOnTouchListener((v, event) -> {
FocusMeteringAction action = new FocusMeteringAction.Builder(
binding.previewView.getMeteringPointFactory()
.createPoint(event.getX(), event.getY())).build();
try {
showTapView((int) event.getX(), (int) event.getY());
mCamera.getCameraControl().startFocusAndMetering(action);
}...
});
}
private void showTapView(int x, int y) {
PopupWindow popupWindow = new PopupWindow(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
ImageView imageView = new ImageView(this);
imageView.setImageResource(R.drawable.ic_focus_view);
popupWindow.setContentView(imageView);
popupWindow.showAsDropDown(binding.previewView, x, y);
binding.previewView.postDelayed(popupWindow::dismiss, 600);
binding.previewView.playSoundEffect(SoundEffectConstants.CLICK);
}
private void takenPictureInternal(boolean isExternal) {
final ContentValues contentValues = new ContentValues();
contentValues.put(MediaStore.MediaColumns.DISPLAY_NAME, CAPTURED_FILE_NAME
+ "_" + picCount++);
contentValues.put(MediaStore.MediaColumns.MIME_TYPE, "image/jpeg");
ImageCapture.OutputFileOptions outputFileOptions =
new ImageCapture.OutputFileOptions.Builder(
getContentResolver(),
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues)
.build();
if (mImageCapture != null) {
mImageCapture.takePicture(outputFileOptions, CameraXExecutors.mainThreadExecutor(),
new ImageCapture.OnImageSavedCallback() {
@Override
public void onImageSaved(@NonNull ImageCapture.OutputFileResults outputFileResults) {
Toast.makeText(DemoActivityLite.this, "Picture got"
+ (outputFileResults.getSavedUri() != null
? " @ " + outputFileResults.getSavedUri().getPath()
: "") + ".", Toast.LENGTH_SHORT)
.show();
}
...
});
}
}
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider,
PreviewView previewView) {
...
mImageCapture = new ImageCapture.Builder()
.setTargetRotation(previewView.getDisplay().getRotation())
.build();
...
// 需要将ImageCapture场景一并绑定
mCamera = cameraProvider.bindToLifecycle(this, cameraSelector, mPreview, mImageCapture);
...
}
public void onAnalyzeGo(View view) {
if (!isAnalyzing) {
mImageAnalysis.setAnalyzer(CameraXExecutors.mainThreadExecutor(), image -> {
analyzeQRCode(image);
});
}
...
}
// 从ImageProxy取出图像数据，交由二维码框架zxing解析
private void analyzeQRCode(@NonNull ImageProxy imageProxy) {
ByteBuffer byteBuffer = imageProxy.getPlanes()[0].getBuffer();
byte[] data = new byte[byteBuffer.remaining()];
byteBuffer.get(data);
...
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Result result;
try {
result = multiFormatReader.decode(bitmap);
}
...
showQRCodeResult(result);
imageProxy.close();
}
private void showQRCodeResult(@Nullable Result result) {
if (binding != null && binding.qrCodeResult != null) {
binding.qrCodeResult.post(() ->
binding.qrCodeResult.setText(result != null ? "Link:\n" + result.getText() : ""));
binding.qrCodeResult.playSoundEffect(SoundEffectConstants.CLICK);
}
}
public void onVideoGo(View view) {
bindPreview(mCameraProvider, binding.previewView, isVideoMode);
}
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider,
PreviewView previewView, boolean isVideo) {
...
mVideoCapture = new VideoCapture.Builder()
.setTargetRotation(previewView.getDisplay().getRotation())
.setVideoFrameRate(25)
.setBitRate(3 * 1024 * 1024)
.build();
cameraProvider.unbindAll();
if (isVideo) {
mCamera = cameraProvider.bindToLifecycle(this, cameraSelector,
mPreview, mVideoCapture);
} else {
mCamera = cameraProvider.bindToLifecycle(this, cameraSelector,
mPreview, mImageCapture, mImageAnalysis);
}
mPreview.setSurfaceProvider(previewView.getSurfaceProvider());
}
public void onCaptureGo(View view) {
if (isVideoMode) {
if (!isRecording) {
// Check permission first.
ensureAudioStoragePermission(REQUEST_STORAGE_VIDEO);
}
}
...
}
private void ensureAudioStoragePermission(int requestId) {
...
if (requestId == REQUEST_STORAGE_VIDEO) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(...);
return;
}
recordVideo();
}
}
private void recordVideo() {
try {
mVideoCapture.startRecording(
new VideoCapture.OutputFileOptions.Builder(getContentResolver(),
MediaStore.Video.Media.EXTERNAL_CONTENT_URI, contentValues)
.build(),
CameraXExecutors.mainThreadExecutor(),
new VideoCapture.OnVideoSavedCallback() {
@Override
public void onVideoSaved(@NonNull VideoCapture.OutputFileResults outputFileResults) {
// Notify user...
}
}
);
}
...
toggleRecordingStatus();
}
private void toggleRecordingStatus() {
// Stop recording when toggle to false.
if (!isRecording && mVideoCapture != null) {
mVideoCapture.stopRecording();
}
}
// VideoCapture.java
public void startRecording(
@NonNull OutputFileOptions outputFileOptions, @NonNull Executor executor,
@NonNull OnVideoSavedCallback callback) {
...
try {
// mAudioRecorder为null将引发NPE终止录制的请求
mAudioRecorder.startRecording();
} catch (IllegalStateException e) {
postListener.onError(ERROR_ENCODER, "AudioRecorder start fail", e);
return;
}
...
mRecordingFuture.addListener(() -> {
...
if (getCamera() != null) {
// 前面发生了NPE,那么将失去此处再次获得AudioRecorder实例的机会
setupEncoder(getCameraId(), getAttachedSurfaceResolution());
notifyReset();
}
}, CameraXExecutors.mainThreadExecutor());
...
}
NightPreviewExtender 夜拍预览 BokehPreviewExtender 人像预览 BeautyPreviewExtender 美顔预览 HdrPreviewExtender HDR预览 AutoPreviewExtender 自动预览
private void bindPreview(@NonNull ProcessCameraProvider cameraProvider,
PreviewView previewView, boolean isVideo) {
Preview.Builder previewBuilder = new Preview.Builder();
ImageCapture.Builder captureBuilder = new ImageCapture.Builder()
.setTargetRotation(previewView.getDisplay().getRotation());
...
setPreviewExtender(previewBuilder, cameraSelector);
mPreview = previewBuilder.build();
setCaptureExtender(captureBuilder, cameraSelector);
mImageCapture = captureBuilder.build();
...
}
private void setPreviewExtender(Preview.Builder builder, CameraSelector cameraSelector) {
BeautyPreviewExtender beautyPreviewExtender = BeautyPreviewExtender.create(builder);
if (beautyPreviewExtender.isExtensionAvailable(cameraSelector)) {
// Enable the extension if available.
beautyPreviewExtender.enableExtension(cameraSelector);
}
}
private void setCaptureExtender(ImageCapture.Builder builder, CameraSelector cameraSelector) {
NightImageCaptureExtender nightImageCaptureExtender = NightImageCaptureExtender.create(builder);
if (nightImageCaptureExtender.isExtensionAvailable(cameraSelector)) {
// Enable the extension if available.
nightImageCaptureExtender.enableExtension(cameraSelector);
}
}
调用CameraProvider的bindToLifecycle()前记得先调用unbindAll()，否则可能发生重复绑定的exception ImageAnalyzer的analyze()在分析完图片之后应立即调用ImageProxy的close()释放图像，以便后续图像能继续传送过来。否则将阻塞回调。因而也要注意分析图像的耗时问题 每个ImageProxy实例在关闭后不要存储它的引用，因为一旦调用close()，这些图像将变得不合法 图像分析结束后应当调用ImageAnalysis的clearAnalyzer()以告知不用将图像流传输过来避免性能的浪费 视频录制场景一定不要忘记获得audio权限
有趣的兼容性处理
class ImageSaveLocationValidator {
// 将判断设备品牌是否为华为或荣耀，是则直接跳过验证
static boolean isValid(final @NonNull ImageCapture.OutputFileOptions outputFileOptions) {
...
if (isSaveToMediaStore(outputFileOptions)) {
// Skip verification on Huawei devices
final HuaweiMediaStoreLocationValidationQuirk huaweiQuirk =
DeviceQuirks.get(HuaweiMediaStoreLocationValidationQuirk.class);
if (huaweiQuirk != null) {
return huaweiQuirk.canSaveToMediaStore();
}
return canSaveToMediaStore(outputFileOptions.getContentResolver(),
outputFileOptions.getSaveCollection(), outputFileOptions.getContentValues());
}
return true;
}
...
}
public class HuaweiMediaStoreLocationValidationQuirk implements Quirk {
static boolean load() {
return "HUAWEI".equals(Build.BRAND.toUpperCase())
|| "HONOR".equals(Build.BRAND.toUpperCase());
}
/**
* Always skip checking if the image capture save destination in
* {@link android.provider.MediaStore} is valid.
*/
public boolean canSaveToMediaStore() {
return true;
}
}
CameraX的优势
易用性，采用封装的API可以高效达到目标 设备一致性，不用在乎版本，忽略设备硬件差异带来的开发区别，达到一致的开发体验 新的相机体验，通过效果扩展可以实现和原生相机一样的美颜等拍摄功能
本文demo
https://github.com/ellisonchan/JetpackDemo
结语
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