Custom component not drawing drawable

Question

I'm trying to learn to create custom views and components, and have already hit a road block. I cannot get any drawable to render on canvas using the drawable.draw(canvas) method. But it works if I get the bitmap and draw it using canvas.drawBitmap() method.

There isn't anything fancy in the code either:

@Override
protected void onDraw(Canvas canvas) {

    // drawing bitmap directly works
    /*
    Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
    canvas.drawBitmap(bitmap, 10, 10, paint);
    */

    // this doesn't work but mThumb is not null in log
    if(mThumb != null) {
        canvas.save();
        mThumb.draw(canvas);
        Log.d("Custom component - ", "mThumb : " + mThumb);
        canvas.restore();
    }
}

The log shows the mThumb variable contains the drawable. I'm getting it the standard way:

if(attrs != null) {
    final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CustomView);
    color = a.getColor(R.styleable.CustomView_cv_color, color);
    thumb = a.getDrawable(R.styleable.CustomView_cv_thumb);
    setThumb(thumb);
    a.recycle();
}

setColor(color);

The xml for the custom view is:

<me.mycustomview.MyCustomView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:cv_color="@android:color/holo_red_light"
    app:cv_thumb="@drawable/ic_launcher" />

And in attrs.xml:

<declare-styleable name="CustomView">
    <attr name="cv_color" format="color" />
    <attr name="cv_thumb" format="reference" />
</declare-styleable>

I'd really appreciate it if someone could point me in the right direction. Thanks!

Answer 1

You might be missing the bounds, try like this

      //try setting bounds before you draw so that OS can know the area in which you want to draw.you may also pass some Rect object while setting up bounds
      mThumb.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
      mThumb.draw(canvas);