public class MainActivity extends AppCompatActivity {

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

        final FalleryOptions falleryOptions = new FalleryBuilder()
                .setImageLoader(YourImageLoader())
                .build();

        this.findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Fallery.startFalleryFromActivityWithOptions(
                        MainActivity.this, 1, falleryOptions
                );
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == RESULT_OK && data != null) {
            String[] result = Fallery.getResultMediasFromIntent(data);
            String caption = Fallery.getCaptionFromIntent(data);
            handleResultWithCaption(result, caption);
        }
    }

    private void handleResultWithCaption(String[] result, String caption) {
        // todo: handle result and caption
    }
}