Implementing CameraX Using Stable API in Java : From Setup to Advanced Use Cases

In this tutorial, we will implement CameraX using Java. The purpose of this post is to provide an updated implementation, as my previous tutorial used the Alpha version of CameraX APIs, which are now outdated.

Watch the Video Tutorial

If you prefer a step-by-step walkthrough, watch the video tutorial below:

1. Setting Up the Project

First, create a new project in Android Studio. In the activity_main.xml layout, replace the default TextView with a PreviewView for camera preview.

Adding Dependencies

Include the following dependencies in your build.gradle file:

        implementation "androidx.camera:camera-core:1.3.0"
        implementation "androidx.camera:camera-camera2:1.3.0"
        implementation "androidx.camera:camera-lifecycle:1.3.0"
        implementation "androidx.camera:camera-view:1.3.0"
        

After adding these dependencies, sync your project.

2. Updating the Layout

Modify activity_main.xml to include a PreviewView for displaying the camera preview and buttons for capturing images and videos.

        <androidx.camera.view.PreviewView
            android:id="@+id/previewView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

        <Button
            android:id="@+id/capturePhoto"
            android:text="Capture Photo"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <Button
            android:id="@+id/captureVideo"
            android:text="Capture Video"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        

3. Implementing CameraX

Before writing CameraX logic, add the following permissions to AndroidManifest.xml:

        <uses-permission android:name="android.permission.CAMERA" />
        <uses-permission android:name="android.permission.RECORD_AUDIO" />
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        

Getting Camera Provider

First, obtain the Camera Provider in MainActivity.java:

        ProcessCameraProvider cameraProvider =
            ProcessCameraProvider.getInstance(this).get();
        

Starting CameraX

Initialize CameraX and bind it to the lifecycle:

        private void startCameraX(ProcessCameraProvider cameraProvider) {
            CameraSelector cameraSelector = new CameraSelector.Builder()
                .requireLensFacing(CameraSelector.LENS_FACING_BACK)
                .build();

            Preview preview = new Preview.Builder().build();
            preview.setSurfaceProvider(previewView.getSurfaceProvider());

            cameraProvider.bindToLifecycle(this, cameraSelector, preview);
        }
        

4. Capturing Images

Implement the image capture functionality:

        ImageCapture imageCapture = new ImageCapture.Builder().build();

        capturePhoto.setOnClickListener(view -> {
            File file = new File(getExternalFilesDir(null), "photo.jpg");
            ImageCapture.OutputFileOptions options =
                new ImageCapture.OutputFileOptions.Builder(file).build();

            imageCapture.takePicture(options, executor, new ImageCapture.OnImageSavedCallback() {
                @Override
                public void onImageSaved(@NonNull ImageCapture.OutputFileResults output) {
                    Toast.makeText(getApplicationContext(), "Photo Captured", Toast.LENGTH_SHORT).show();
                }

                @Override
                public void onError(@NonNull ImageCaptureException exception) {
                    exception.printStackTrace();
                }
            });
        });
        

5. Capturing Videos

To record videos, use the new CameraX Recorder API:

        VideoCapture videoCapture = new VideoCapture.Builder().build();

        captureVideo.setOnClickListener(view -> {
            if (recording == null) {
                File file = new File(getExternalFilesDir(null), "video.mp4");
                VideoCapture.OutputFileOptions options =
                    new VideoCapture.OutputFileOptions.Builder(file).build();

                recording = videoCapture.getOutput()
                    .prepareRecording(getApplicationContext(), options)
                    .start(ContextCompat.getMainExecutor(this), event -> {
                        if (event instanceof VideoRecordEvent.Start) {
                            captureVideo.setText("Stop Recording");
                        } else if (event instanceof VideoRecordEvent.Finalize) {
                            captureVideo.setText("Capture Video");
                            recording = null;
                            Toast.makeText(this, "Video Saved", Toast.LENGTH_SHORT).show();
                        }
                    });
            } else {
                recording.stop();
                recording = null;
            }
        });
        

6. Running the Application

After implementing the above code, run the application. You should be able to preview the camera, capture images, and record videos. Ensure you have granted camera and storage permissions in the app settings.

Conclusion

In this tutorial, we implemented CameraX in Java, covering preview, image capture, and video recording using the latest APIs. If you found this guide helpful, feel free to check out more tutorials on our channel!