android button setPressed after onClick

Just to note this is because Android is changing the setPressed both before and after your onClickEvent, so changing it yourself has no effect. Another way to get around this is to use the onTouchEvent.

button.setOnTouchListener(new OnTouchListener() {

    @Override
    public boolean onTouch(View v, MotionEvent event) {

        // show interest in events resulting from ACTION_DOWN
        if (event.getAction() == MotionEvent.ACTION_DOWN) return true;

        // don't handle event unless its ACTION_UP so "doSomething()" only runs once.
        if (event.getAction() != MotionEvent.ACTION_UP) return false;

        doSomething();
        button.setPressed(true);                    
        return true;
   }
});

Use ToggleButton instead of Button.

<ToggleButton
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:background="@drawable/topping_selector"
    android:checked="false"
    android:textOff="Topping2"
    android:textOn="Topping2" />

topping_selector.xml:

<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:state_checked="true" 
        android:drawable="@drawable/btn_topping_on" />

    <item android:state_checked="false" 
        android:drawable="@drawable/btn_topping_off" />

</selector>