為什么推薦使用Jetpack CameraX？
大家好，我是皇叔，最近開了一個安卓進階漲薪訓練營，可以幫助大家突破技術(shù)&職場瓶頸，從而度過難關(guān)，進入心儀的公司。
詳情見文章：沒錯！皇叔開了個訓練營
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;
// 綁定前確保解除了所有綁定，防止CameraProvider重復綁定到Lifecycle發(fā)生異常
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();
...
// 需要將ImageCapture場景一并綁定
mCamera = cameraProvider.bindToLifecycle(this, cameraSelector, mPreview, mImageCapture);
...
}
public void onAnalyzeGo(View view) {
if (!isAnalyzing) {
mImageAnalysis.setAnalyzer(CameraXExecutors.mainThreadExecutor(), image -> {
analyzeQRCode(image);
});
}
...
}
// 從ImageProxy取出圖像數(shù)據(jù)，交由二維碼框架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為null將引發(fā)NPE終止錄制的請求
mAudioRecorder.startRecording();
} catch (IllegalStateException e) {
postListener.onError(ERROR_ENCODER, "AudioRecorder start fail", e);
return;
}
...
mRecordingFuture.addListener(() -> {
...
if (getCamera() != null) {
// 前面發(fā)生了NPE,那么將失去此處再次獲得AudioRecorder實例的機會
setupEncoder(getCameraId(), getAttachedSurfaceResolution());
notifyReset();
}
}, CameraXExecutors.mainThreadExecutor());
...
}
NightPreviewExtender 夜拍預覽 BokehPreviewExtender 人像預覽 BeautyPreviewExtender 美顔預覽 HdrPreviewExtender HDR預覽 AutoPreviewExtender 自動預覽
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);
}
}
調(diào)用CameraProvider的bindToLifecycle()前記得先調(diào)用unbindAll()，否則可能發(fā)生重復綁定的exception ImageAnalyzer的analyze()在分析完圖片之后應(yīng)立即調(diào)用ImageProxy的close()釋放圖像，以便后續(xù)圖像能繼續(xù)傳送過來。否則將阻塞回調(diào)。因而也要注意分析圖像的耗時問題 每個ImageProxy實例在關(guān)閉后不要存儲它的引用，因為一旦調(diào)用close()，這些圖像將變得不合法 圖像分析結(jié)束后應(yīng)當調(diào)用ImageAnalysis的clearAnalyzer()以告知不用將圖像流傳輸過來避免性能的浪費 視頻錄制場景一定不要忘記獲得audio權(quán)限
有趣的兼容性處理
class ImageSaveLocationValidator {
// 將判斷設(shè)備品牌是否為華為或榮耀，是則直接跳過驗證
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的優(yōu)勢
易用性，采用封裝的API可以高效達到目標 設(shè)備一致性，不用在乎版本，忽略設(shè)備硬件差異帶來的開發(fā)區(qū)別，達到一致的開發(fā)體驗 新的相機體驗，通過效果擴展可以實現(xiàn)和原生相機一樣的美顏等拍攝功能
本文demo
https://github.com/ellisonchan/JetpackDemo
結(jié)語
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