StateListDrawable to switch colorfilters

Question

I want to create custom buttons to use in a TabHost. I haven been trying to just use the same image resource (png), but have the colorfilter change depending on the state. S

Answer 1

OK, I never got the above code to work, so here's what I ended up doing.

First, I subclassed LayerDrawable:

public class StateDrawable extends LayerDrawable {

    public StateDrawable(Drawable[] layers) {
        super(layers);
    }

    @Override
    protected boolean onStateChange(int[] states) {
        for (int state : states) {
            if (state == android.R.attr.state_selected) {
                super.setColorFilter(Color.argb(255, 255, 195, 0), PorterDuff.Mode.SRC_ATOP);
            } else {
                super.setColorFilter(Color.GRAY, PorterDuff.Mode.SRC_ATOP);
            }
        }
        return super.onStateChange(states);
    }

    @Override
    public boolean isStateful() {
        return true;
    }

}

I changed the buildTab() method to the following:

private View buildTab(int icon, int label) {
    LayoutInflater inflater = LayoutInflater.from(this);
    View view = inflater.inflate(R.layout.tab_button, null);
    ((ImageView) view.findViewById(R.id.tab_icon)).setImageDrawable(new StateDrawable(new Drawable[] { getResources()
          .getDrawable(icon) }));
    ((TextView) view.findViewById(R.id.tab_text)).setText(getString(label));
    return view;
}

I still add the tabs like this:

Intent fooIntent = new Intent().setClass(this, FooActivity.class);
tabHost.addTab(tabHost.newTabSpec(TAB_NAME_INFO).setIndicator(buildTab(R.drawable.tab_icon_info, R.string.info)).setContent(infoIntent));

This works for me, compatible with android 1.6.