CameraX：如何使用图像调用分析方法

Question

我正在尝试分析使用 Android 的 CameraX 获得的最新图像。在这个阶段，我使用的是 androidx.camera:camera-camera2 1.0.0-alpha05 版本。在我的 MainActivity.java 中，我不知道如何将最新图像放入分析 (ImageProxy image, int rotationDegrees) 方法中。

我如何以及在哪里获得最新的图像，然后将其传递给分析方法？

我的代码如下所示

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "Christo";

    private int REQUEST_CODE_PERMISSIONS = 101;
    private final String[] REQUIRED_PERMISSIONS = new String[]{"android.permission.CAMERA", "android.permission.WRITE_EXTERNAL_STORAGE"};
    TextureView textureView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textureView = findViewById(R.id.view_finder);

        if(allPermissionsGranted()){
            startCamera(); //start camera if permission has been granted by user
        } else{
            ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS);
        }
    }

    private void startCamera() {

        Log.v(TAG, "startCamera()");

        CameraX.unbindAll();

        Rational aspectRatio = new Rational (textureView.getWidth(), textureView.getHeight());

        Size screen = new Size(textureView.getWidth(), textureView.getHeight()); //size of the screen

        PreviewConfig pConfig = new PreviewConfig.Builder()
                .setTargetAspectRatio(aspectRatio) //AspectRatio.RATIO_4_3
                .setTargetResolution(screen)
                //.setLensFacing(CameraX.LensFacing.FRONT)
                .build();
        Preview preview = new Preview(pConfig);

        preview.setOnPreviewOutputUpdateListener(
                new Preview.OnPreviewOutputUpdateListener() {
                    @Override
                    public void onUpdated(Preview.PreviewOutput output){
                        ViewGroup parent = (ViewGroup) textureView.getParent();
                        parent.removeView(textureView);
                        parent.addView(textureView, 0);

                        textureView.setSurfaceTexture(output.getSurfaceTexture());
                        updateTransform();
                    }
                });

        ImageCaptureConfig imageCaptureConfig = new ImageCaptureConfig.Builder().setCaptureMode(ImageCapture.CaptureMode.MIN_LATENCY)
                .setTargetRotation(getWindowManager().getDefaultDisplay().getRotation()).build();

        final ImageCapture imgCap = new ImageCapture(imageCaptureConfig);

        findViewById(R.id.imgCapture).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                final String timeStamp = new SimpleDateFormat("MM_dd_HH_mm_ss").format(new Date());

                File file = new File(Environment.getExternalStorageDirectory() + "/Christo/pic" + timeStamp + ".png");

                imgCap.takePicture(file, new ImageCapture.OnImageSavedListener() {
                    @Override
                    public void onImageSaved(@NonNull File file) {
                        String msg = "Pic captured at " + file.getAbsolutePath();
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onError(@NonNull ImageCapture.ImageCaptureError useCaseError, @NonNull String message, @Nullable Throwable cause) {
                        String msg = "Pic capture failed : " + message;
                        Toast.makeText(getBaseContext(), msg,Toast.LENGTH_LONG).show();
                        if(cause != null){
                            cause.printStackTrace();
                        }
                    }
                });
            }
        });

        ImageAnalysisConfig imageConfig = new ImageAnalysisConfig.Builder().setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE).build();
        ImageAnalysis analysis = new ImageAnalysis(imageConfig);

        analysis.setAnalyzer(

                new ImageAnalysis.Analyzer(){

                    @Override
                    public void analyze(ImageProxy image, int rotationDegrees){

                        Log.v(TAG, "analyze");

                        // My code to analyze image - yet to be developed

                    }
                });

        //bind to lifecycle:
        CameraX.bindToLifecycle((LifecycleOwner)this, preview, imgCap);
    }

    private void updateTransform(){

        Log.v(TAG, "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);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

        if(requestCode == REQUEST_CODE_PERMISSIONS){
            if(allPermissionsGranted()){
                startCamera();
            } 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;
    }
}

...

Answer 1

public void analyze 现在正在使用下面的代码。我一直在尝试升级到 1.0.0-alpha10 版本，但我被困在 1.0.0-alpha05 版本。我会坚持下去的。

package com.chris.chris_camerax;

import android.content.pm.PackageManager;
import android.graphics.Matrix;
import android.media.Image;
import android.os.Bundle;
import android.util.Log;
import android.util.Rational;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;
import android.view.ViewGroup;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.CameraX;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageAnalysisConfig;
import androidx.camera.core.ImageProxy;
import androidx.camera.core.Preview;
import androidx.camera.core.PreviewConfig;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;


public class MainActivity 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;

    private static final String TAG = "Christo";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textureView = findViewById(R.id.view_finder);

        if(allPermissionsGranted()){
            startCamera(); //start camera if permission has been granted by user
        } else{
            ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS);
        }
    }

    private void startCamera() {

        Log.v(TAG, "startCamera()");

        CameraX.unbindAll();

        Rational aspectRatio = new Rational (textureView.getWidth(), textureView.getHeight());
        Size screen = new Size(textureView.getWidth(), textureView.getHeight()); //size of the screen

        PreviewConfig pConfig = new PreviewConfig.Builder()
                .setTargetAspectRatio(aspectRatio)
                //.setTargetAspectRatio(AspectRatio.RATIO_4_3)
                //.setTargetResolution(screen)
                //.setLensFacing(CameraX.LensFacing.FRONT)
                .build();

        Preview preview = new Preview(pConfig);

        preview.setOnPreviewOutputUpdateListener(
                new Preview.OnPreviewOutputUpdateListener() {
                    @Override
                    public void onUpdated(Preview.PreviewOutput output){
                        ViewGroup parent = (ViewGroup) textureView.getParent();
                        parent.removeView(textureView);
                        parent.addView(textureView, 0);

                        textureView.setSurfaceTexture(output.getSurfaceTexture());
                        updateTransform();
                    }
                });

        ImageAnalysisConfig iAC = new ImageAnalysisConfig.Builder()
                .setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE)
                .build();

        ImageAnalysis imageAnalyzer =
                new ImageAnalysis(iAC);
                        //.setTargetResolution(new Size(1280, 720))
                        //.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
                        //.build();

        imageAnalyzer.setAnalyzer(
                new ImageAnalysis.Analyzer() {
                    @Override
                    public void analyze(ImageProxy image, int rotationDegrees) {
                        // insert your code here.
                        Log.v(TAG, "analyze");

                        Image img = image.getImage();


                    }
                });

        //bind to lifecycle:
        CameraX.bindToLifecycle(this, preview, imageAnalyzer);
    }

    private void updateTransform(){

        Log.v(TAG, "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);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

        if(requestCode == REQUEST_CODE_PERMISSIONS){
            if(allPermissionsGranted()){
                startCamera();
            } 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;
    }
}