前言
開發環境是Android studio 北極狐，CameraX1.0.0-alpha02，實現語言是Java。
創建工程
1.引入CameraX
在build.gradle添加要引入CameraX的版本。
//CameraXdef camerax_version
= "1.0.0-alpha02"implementation
"androidx.camera:camera-core:${camerax_version}"implementation
"androidx.camera:camera-camera2:${camerax_version}"
2.在AndroidManifest.xml添加打開攝像頭的權限和讀寫文件的權限。
<uses-permission android:name
="android.permission.CAMERA" /
><uses-permission android:name
="android.permission.WRITE_EXTERNAL_STORAGE" /
><uses-permission android:name
="android.permission.READ_EXTERNAL_STORAGE" /
>
android:requestLegacyExternalStorage
="true"
3.在工程里面新添加一個Activity。
4.CameraXDemo代碼。
public class IdentificationPhoto extends AppCompatActivity
{private int REQUEST_CODE_PERMISSIONS
= 101;private final String [] REQUIRED_PERMISSIONS
=new String[] {"android.permission.CAMERA","android.permission.WRITE_EXTERNAL_STORAGE"};TextureView textureView
;ImageView cameraFlip
;private int backlensfacing
= 0;private int flashLamp
= 0;@Overrideprotected void onCreate(Bundle savedInstanceState
){super.onCreate(savedInstanceState
);setContentView(R.layout
.activity_camerax_demo
);getSupportActionBar().hide();if(Build.VERSION
.SDK_INT
>= Build.VERSION_CODES
.KITKAT
) {getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS
);getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION
);}textureView
= findViewById(R.id
.view_camera
);cameraFlip
= findViewById(R.id
.btn_switch_camera
);cameraFlip
.setOnClickListener(new View.OnClickListener(){@Overridepublic void onClick(View view
){if(backlensfacing
== 0){startCamera(CameraX.LensFacing.FRONT
);backlensfacing
= 1;}else if(backlensfacing
== 1){startCamera(CameraX.LensFacing.BACK
);backlensfacing
= 0;}}});if(allPermissionsGranted()){startCamera(CameraX.LensFacing.BACK
);}else {ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS
, REQUEST_CODE_PERMISSIONS
);}}private void startCamera(CameraX.LensFacing CAMERA_ID
){unbindAll();Rational aspectRatio
= new Rational(textureView
.getWidth(), textureView
.getHeight());Size screen
= new Size(textureView
.getWidth(),textureView
.getHeight());PreviewConfig pConfig
;Preview preview
;pConfig
= new PreviewConfig.Builder().setLensFacing(CAMERA_ID
).setTargetAspectRatio(aspectRatio
).setTargetResolution(screen
).build();preview
= new Preview(pConfig
);preview
.setOnPreviewOutputUpdateListener(new Preview.OnPreviewOutputUpdateListener() {@Overridepublic void onUpdated(Preview.PreviewOutput output
){ViewGroup parent
= (ViewGroup)textureView
.getParent();parent
.removeView(textureView
);parent
.addView(textureView
,0);textureView
.setSurfaceTexture(output
.getSurfaceTexture());updateTransform();}});final ImageCaptureConfig imageCaptureConfig
;imageCaptureConfig
= new ImageCaptureConfig.Builder().setCaptureMode(ImageCapture.CaptureMode.MAX_QUALITY
).setTargetRotation(getWindowManager().getDefaultDisplay().getRotation()).setLensFacing(CAMERA_ID
).build();final ImageCapture imgCap
= new ImageCapture(imageCaptureConfig
);findViewById(R.id
.btn_flash
).setOnClickListener(new View.OnClickListener(){@Overridepublic void onClick(View view
){if (flashLamp
== 0){flashLamp
= 1;imgCap
.setFlashMode(FlashMode.OFF
);Toast.makeText(getBaseContext(), "Flash Disable", Toast.LENGTH_SHORT
).show();}else if(flashLamp
== 1){flashLamp
= 0;imgCap
.setFlashMode(FlashMode.ON
);Toast.makeText(getBaseContext(), "Flash Enable", Toast.LENGTH_SHORT
).show();}}});findViewById(R.id
.btn_takePict
).setOnClickListener(new View.OnClickListener(){@Overridepublic void onClick(View view
){File image
= null;String timeStamp
= new SimpleDateFormat("yyyMMdd_HHmmss").format(new Date());String imageFileName
= "JPEG_"+ timeStamp
+ "_";File storageDir
= getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES
);try {image
= File.createTempFile(imageFileName
,".jpeg",storageDir
);}catch (IOException e
){e
.printStackTrace();}File file
= new File(image
.getAbsolutePath());imgCap
.takePicture(file
, new ImageCapture.OnImageSavedListener(){@Overridepublic void onImageSaved(@NonNull File file
){String msg
= "Pic saved at "+ file
.getAbsolutePath();galleryAddPic(file
.getAbsolutePath());Toast.makeText(getBaseContext(), msg
,Toast.LENGTH_LONG
).show();}@Overridepublic void onError(@NonNull ImageCapture.UseCaseError useCaseError
, @NonNull String message
, @Nullable Throwable cause
) {String msg
= "Pic saved at "+ message
;Toast.makeText(getBaseContext(), msg
,Toast.LENGTH_LONG
).show();if (cause
!=null){cause
.printStackTrace();Toast.makeText(getBaseContext(), cause
.toString(),Toast.LENGTH_LONG
).show();}}});}});bindToLifecycle(this,preview
, imgCap
);}private void galleryAddPic(String currentFilePath
){Intent mediaScanIntent
= new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE
);File file
= new File (currentFilePath
);Uri contentUri
= Uri.fromFile(file
);mediaScanIntent
.setData(contentUri
);this.sendBroadcast(mediaScanIntent
);}private void updateTransform(){Matrix mx
= new Matrix();float w
= textureView
.getMeasuredWidth();float h
= textureView
.getMeasuredHeight();float cX
= w
/ 2f;float cY
= h
/ 2f;int rotationDgr
;int rotation
= (int)textureView
.getRotation();switch (rotation
){case Surface.ROTATION_0
:rotationDgr
= 0;break;case Surface.ROTATION_90
:rotationDgr
= 90;break;case Surface.ROTATION_180
:rotationDgr
= 180;break;case Surface.ROTATION_270
:rotationDgr
= 270;break;default: return;}mx
.postRotate((float)rotationDgr
, cX
,cY
);textureView
.setTransform(mx
);}@RequiresApi(api
= Build.VERSION_CODES
.LOLLIPOP
)@Overridepublic void onRequestPermissionsResult(int requestCode
, @NonNull String[] permissions
, @NonNull int[] grantResults
) {super.onRequestPermissionsResult(requestCode
, permissions
, grantResults
);if(requestCode
== REQUEST_CODE_PERMISSIONS
){if (allPermissionsGranted()) {startCamera(CameraX.LensFacing.BACK
);}else{Toast.makeText(this, "Permissions not granted by the user.", Toast.LENGTH_SHORT
).show();finish();}}}private boolean allPermissionsGranted(){for(String permission
: REQUIRED_PERMISSIONS
){if(ContextCompat.checkSelfPermission(this, permission
)!= PackageManager.PERMISSION_GRANTED
){return false;}}return true;}private boolean checkCameraHardware(Context context
){return context
.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA
);}private void toggleFrontBackCamera(){}
}
5.在布局文件里面添加
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".CameraXDome"><TextureViewandroid:id="@+id/view_camera"android:layout_width="0dp"android:layout_height="0dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="1.0"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"app:layout_constraintVertical_bias="0.0" /><ImageButtonandroid:id="@+id/btn_takePict"android:layout_width="wrap_content"android:layout_height="wrap_content"android:src="@drawable/ic_camera"android:layout_marginBottom="30dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintEnd_toEndOf="parent"></ImageButton><ImageButtonandroid:id="@+id/btn_flash"android:layout_width="wrap_content"android:layout_height="wrap_content"android:src="@drawable/ic_flash"android:layout_marginBottom="35dp"android:layout_marginStart="20dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintStart_toStartOf="parent"></ImageButton><ImageButtonandroid:id="@+id/btn_switch_camera"android:layout_width="wrap_content"android:layout_height="wrap_content"android:src="@drawable/ic_switch_camera"android:layout_marginBottom="30dp"android:layout_marginStart="330dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintStart_toStartOf="parent"></ImageButton></androidx.constraintlayout.widget.ConstraintLayout>
6.運行APP，因為模擬器沒有前視攝像頭，上真機調試就可以看到效果。
總結
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