CameraxActivity.java

package com.asmaamir.mlkitdemo.CameraX;

import android.annotation.SuppressLint;
import android.content.pm.PackageManager;
import android.graphics.Matrix;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.CameraInfoUnavailableException;
import androidx.camera.core.CameraX;
import androidx.camera.core.CameraX.LensFacing;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageAnalysisConfig;
import androidx.camera.core.ImageCapture;
import androidx.camera.core.ImageCaptureConfig;
import androidx.camera.core.Preview;
import androidx.camera.core.PreviewConfig;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import com.asmaamir.mlkitdemo.R;

import java.io.File;


/*
 * Example: https://codelabs.developers.google.com/codelabs/camerax-getting-started/#0
 */

public class CameraxActivity extends AppCompatActivity {
    private TextureView tv;
    private static final String TAG = "CameraxActivity";
    public static final int REQUEST_CODE_PERMISSION = 101;
    public static final String[] REQUIRED_PERMISSIONS = new String[]{"android.permission.CAMERA", "android.permission.WRITE_EXTERNAL_STORAGE"};

    public static LensFacing lens = LensFacing.FRONT;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camerax);
        tv = findViewById(R.id.texture_view);
        if (allPermissionsGranted()) {
            tv.post(this::startCamera);
        } else {
            ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSION);
        }
        tv.addOnLayoutChangeListener((v, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom) -> updateTransform());
    }

    @SuppressLint("RestrictedApi")
    private void startCamera() {
        initCamera();
        ImageButton ibSwitch = findViewById(R.id.btn_switch);
        ibSwitch.setOnClickListener(v -> {
            if (lens == LensFacing.FRONT)
                lens = LensFacing.BACK;
            else
                lens = LensFacing.FRONT;
            try {
                Log.i(TAG, "" + lens);
                CameraX.getCameraWithLensFacing(lens);
                initCamera();
            } catch (CameraInfoUnavailableException e) {
                Log.e(TAG, e.toString());
            }
        });
    }

    private void initCamera() {
        CameraX.unbindAll();
        PreviewConfig pc = new PreviewConfig
                .Builder()
                .setLensFacing(lens)
                .setTargetResolution(new Size(tv.getWidth(), tv.getHeight()))
                .build();

        Preview preview = new Preview(pc);
        preview.setOnPreviewOutputUpdateListener(output -> {
            ViewGroup vg = (ViewGroup) tv.getParent();
            vg.removeView(tv);
            vg.addView(tv, 0);
            tv.setSurfaceTexture(output.getSurfaceTexture());
            updateTransform();
        });
        ImageCaptureConfig icc = new ImageCaptureConfig
                .Builder()
                .setLensFacing(lens)
                .setCaptureMode(ImageCapture.CaptureMode.MAX_QUALITY)
                .build();
        ImageCapture imgCap = new ImageCapture(icc);
        ImageButton ib = findViewById(R.id.img_cap);
        ib.setOnClickListener(v -> {
            File file = new File(Environment.getExternalStorageDirectory() + "/" + System.currentTimeMillis() + ".png");
            imgCap.takePicture(file, (Runnable::run), new ImageCapture.OnImageSavedListener() {
                @Override
                public void onImageSaved(@NonNull File file) {
                    String msg = "Image is saved at: " + file.getAbsolutePath();
                    runOnUiThread(() -> Toast.makeText(getBaseContext(), msg, Toast.LENGTH_SHORT).show());
                    Log.i(TAG, msg);
                }

                @Override
                public void onError(@NonNull ImageCapture.ImageCaptureError imageCaptureError, @NonNull String message, @Nullable Throwable cause) {
                    Log.e(TAG, "An error occurred while saving:" + message);
                }
            });
        });
        ImageAnalysisConfig iac = new ImageAnalysisConfig
                .Builder()
                .setLensFacing(lens)
                .setImageReaderMode(ImageAnalysis.ImageReaderMode.ACQUIRE_LATEST_IMAGE)
                .build();

        ImageAnalysis imageAnalysis = new ImageAnalysis(iac);
        imageAnalysis.setAnalyzer(Runnable::run,
                new DemoAnalyzer());
        CameraX.bindToLifecycle(this, preview, imgCap, imageAnalysis);
    }

    private void updateTransform() {
        Matrix mat = new Matrix();
        float centerX = tv.getWidth() / 2.0f;
        float centerY = tv.getHeight() / 2.0f;

        float rotationDegrees;
        switch (tv.getDisplay().getRotation()) {
            case Surface.ROTATION_0:
                rotationDegrees = 0;
                break;
            case Surface.ROTATION_90:
                rotationDegrees = 90;
                break;
            case Surface.ROTATION_180:
                rotationDegrees = 180;
                break;
            case Surface.ROTATION_270:
                rotationDegrees = 270;
                break;
            default:
                return;
        }
        mat.postRotate(rotationDegrees, centerX, centerY);
        tv.setTransform(mat);

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CODE_PERMISSION) {
            if (allPermissionsGranted()) {
                tv.post(this::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;
    }

}