Android CameraX Sample

README.md

Android CameraX Sample

The sample source was only Kotlin, so I rewrite it in Java. Operation has been verified with the actual machine and API 28 emulator. Please give the camera permission to the application from the Android settings.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextureView
        android:id="@+id/textureView"
        android:layout_width="480px"
        android:layout_height="640px"
        android:layout_marginTop="16dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="480px"
        android:layout_height="640px"
        android:layout_margin="16dp"
        app:srcCompat="@mipmap/ic_launcher"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textureView" />

    <ImageButton
        android:id="@+id/imageButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        app:srcCompat="@android:drawable/ic_menu_camera"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

AndroidManifest.xml

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

build.gradle

android {
    compileSdkVersion 29
    defaultConfig {
        minSdkVersion 21
        targetSdkVersion 29
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'

    def camerax_version = "1.0.0-alpha05"
    implementation "androidx.camera:camera-core:${camerax_version}"
    implementation "androidx.camera:camera-camera2:${camerax_version}"
}

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.*;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.util.Log;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;

import java.nio.ByteBuffer;

public class MainActivity extends AppCompatActivity
{
    private TextureView textureView;

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

        textureView = findViewById(R.id.textureView);

        textureView.post((Runnable)(new Runnable()
        {
            public final void run()
            {
                startCamera();
            }
        }));

        textureView.addOnLayoutChangeListener(new View.OnLayoutChangeListener()
        {
            @Override
            public void onLayoutChange(View view, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom)
            {
                updateTransform();
            }
        });
    }

    private void startCamera()
    {
        PreviewConfig.Builder previewConfig = new PreviewConfig.Builder();

        Preview preview = new Preview(previewConfig.build());

        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.Builder imageCaptureConfig = new ImageCaptureConfig.Builder();

        final ImageCapture imageCapture = new ImageCapture(imageCaptureConfig.build());

        ImageButton button = findViewById(R.id.imageButton);
        button.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                imageCapture.takePicture(new ImageCapture.OnImageCapturedListener()
                {
                    @Override
                    public void onCaptureSuccess(ImageProxy image, int rotationDegrees)
                    {
                        ImageView imageView = findViewById(R.id.imageView);
                        imageView.setImageBitmap(imageProxyToBitmap(image));
                        imageView.setRotation(rotationDegrees);

                        image.close();
                    }
                });
            }
        });

        CameraX.bindToLifecycle(this, preview, imageCapture);
    }


    private void updateTransform()
    {
        Matrix matrix = new Matrix();

        float centerX = textureView.getWidth() / 2f;
        float centerY = textureView.getHeight() / 2f;

        float rotationDegrees = 0f;
        switch (textureView.getDisplay().getRotation())
        {
            case Surface.ROTATION_0:
                rotationDegrees = 0f;
                break;

            case Surface.ROTATION_90:
                rotationDegrees = 90f;
                break;

            case Surface.ROTATION_180:
                rotationDegrees = 180f;
                break;

            case Surface.ROTATION_270:
                rotationDegrees = 270f;
                break;

            default:
                return;
        }

        matrix.postRotate(-rotationDegrees, centerX, centerY);

        textureView.setTransform(matrix);
    }


    private Bitmap imageProxyToBitmap(ImageProxy image)
    {
        ImageProxy.PlaneProxy planeProxy = image.getPlanes()[0];
        ByteBuffer buffer = planeProxy.getBuffer();
        byte[] bytes = new byte[buffer.remaining()];
        buffer.get(bytes);

        return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
    }
}