Android app

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "HEIC to JPEG Converter";
    private static final int REQUEST_PICK_HEIC_FILE = 1;
    private static final int REQUEST_PICK_JPEG_FILE = 2;

    private Button mPickHeicButton;
    private Button mPickJpegButton;

    private File mHeicFile;
    private File mJpegFile;

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

        mPickHeicButton = findViewById(R.id.pick_heic_button);
        mPickJpegButton = findViewById(R.id.pick_jpeg_button);

        mPickHeicButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Open the file picker dialog to select the input HEIC file
                Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
                intent.addCategory(Intent.CATEGORY_OPENABLE);
                intent.setType("image/heic");
                startActivityForResult(intent, REQUEST_PICK_HEIC_FILE);
            }
        });

        mPickJpegButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Open the file picker dialog to select the output JPEG file
                Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
                intent.addCategory(Intent.CATEGORY_OPENABLE);
                intent.setType("image/jpeg");
                intent.putExtra(Intent.EXTRA_TITLE, "output.jpg");
                startActivityForResult(intent, REQUEST_PICK_JPEG_FILE);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            if (requestCode == REQUEST_PICK_HEIC_FILE) {
                // Get the selected HEIC file
                if (data != null && data.getData() != null) {
                    mHeicFile = new File(getFilePathFromUri(data.getData()));
                    Log.d(TAG, "Selected HEIC file: " + mHeicFile.getAbsolutePath());
                }
            } else if (requestCode == REQUEST_PICK_JPEG_FILE) {
                // Get the selected JPEG file
                if (data != null && data.getData() != null) {
                    mJpegFile = new File(getFilePathFromUri(data.getData()));
                    Log.d(TAG, "Selected JPEG file: " + mJpegFile.getAbsolutePath());
                }
            }

            // Check if both files are selected and convert HEIC to JPEG
            if (mHeicFile != null && mJpegFile != null) {
                HEICToJPEGConverter converter = new HEICToJPEGConverter();
                converter.convert(mHeicFile.getAbsolutePath(), mJpegFile.getAbsolutePath());
                Log.d(TAG, "Conversion complete.");
            }
        }
    }

    private String getFilePathFromUri(Uri uri) {
        String filePath = null;
        String[] projection = {MediaStore.Images.Media.DATA};
        Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
        if (cursor != null && cursor.moveToFirst()) {
            int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            filePath = cursor.getString(columnIndex);
            cursor.close();
        }
        return filePath;
    }
}