是否可以在自定义View类中创建另一个控件？

public class CustomClass extends FrameLayout {
    Context c;
    ProgressBar progressBar;
    ImageView imageView;
    public CustomClass(Context context) {
       super(context);
       loadControls(context);
    }
    public CustomClass(Context context, AttributeSet attrs) {
        super(context, attrs);
        loadControls(context);
    }
    public CustomClass(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        loadControls(context);
    }
    public void loadControls(Context context)
    {
        c = context;
        progressBar = new ProgressBar(c, null, android.R.attr.progressBarStyleInverse);
        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.MATCH_PARENT, Gravity.TOP | Gravity.LEFT);

        imageView = new ImageView(c);
        imageView.setScaleType(ImageView.ScaleType.FIT_XY);
        //imageView.setBackgroundColor(color.darker_gray);
       addView(imageView, params);
       params = new FrameLayout.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL);
    addView(progressBar, params);
    progressBar.setVisibility(View.VISIBLE);
   }}