图像视图选择器在类中的奇怪行为，它扩展了imageview

Question

我正在尝试向对象添加一个简单的选择器 - imageView - 这是扩展imageview的类的实例。

final PackageTypeView ptv = packageTypeViewsList.get(index);
            index++;

             Drawable drawable = getResources().getDrawable(
                    R.drawable.selector);

             ImageTitleView imageView = new ImageTitleView(
                    getActivity());

            imageView.setImageBitmap(BeanUtils.decodeSampledBitmapFromResource(new File(ptv.getTileRenderPath()), screenWidth, screenWidth));

            if (ptv.getTitleBgArgb() != null) {
                imageView.setColorCode(ptv.getTitleBgArgb());
            }


            imageView.setImageDrawable(drawable);

            //TODO check this entry in the database
            if (ptv.isShowingTitle()) {
                imageView.setDescription(ptv.getName());
            }

            imageView.setScaleType(ScaleType.CENTER_CROP);
            imageView.setClickable(true);
            // imageView.setImageResource(R.drawable.selector);
            imageView.setOnClickListener(this);
            imageView.setTag(ptv.getId());

这是ImageTitleView类。

public class ImageTitleView extends ImageView {

    private String description;

    private String colorCode = "aaaaaaBB";

    private static float fontSize = -1;

    private Paint paint = new Paint();

    private Rect rect = new Rect();

    private Bitmap bitmap = null;

    private static Typeface tf = Typeface.create("Helvetica", Typeface.BOLD);

    public ImageTitleView(Context context, Bitmap bitmap) {
        super(context);
        initPaint(context);
        this.bitmap = bitmap;
    }

    public ImageTitleView(Context context) {
        super(context);
        initPaint(context);
    }

    public ImageTitleView(Context context, String description) {
        super(context);
        this.description = description;
        initPaint(context);
    }

    public ImageTitleView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initPaint(context);
    }

    public ImageTitleView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initPaint(context);
    }

    private void initPaint(Context context) {
        fontSize = context.getResources().getDimension(R.dimen.text_size_grid_info);
        paint.setTextSize(fontSize);
        paint.setTypeface(tf);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);

        if (description != null) {
            rect.set(new Rect(0, canvas.getHeight() - (canvas.getHeight() / 4), canvas.getWidth(), canvas.getHeight()));
            paint.setColor(Color.parseColor("#" + colorCode));
            canvas.drawRect(rect, paint);

            float y = rect.top + ( (rect.bottom - rect.top) / 2 + fontSize / 2);
            paint.setColor(Color.WHITE);
            canvas.drawText(description, 15, y, paint);

        }
    }

    The problem is the the following when I add the selector the imageView's bitmap is replaced  with 

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getColorCode() {
        return colorCode;
    }

    public void setColorCode(String colorCode) {
        if (colorCode != null && !colorCode.isEmpty()) {
            this.colorCode = colorCode;
        }
    }

    @Override
    public void setClickable(boolean clickable) {   
        super.setClickable(clickable);
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);       
    }
}

这是选择器：

<item android:state_pressed="true" android:drawable="@color/button_pressed_color"/>
<item android:state_focused="true" android:drawable="@color/button_pressed_color"/>
<item android:drawable="@android:color/transparent"/>

问题是选择器会更改imageView对象的背景，并用透明背景替换此对象的位图。