title: NumberPicker, intercept when picker stop scrolling
body: <p>I need to implement a View with two numberPicker, pickerOne and pickerTwo. pickerTwo values depending on current value of pickerOne, so when user scroll pickerOne, values inside pickerTwo change. I've implement pickerOne like:</p>
  
  <pre><code> NumberPicker pickerOne= new NumberPicker(context);
  
   pickerOne.setLayoutParams(new LinearLayout.LayoutParams(
              ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
   pickerOne.setDescendantFocusability(NumberPicker.FOCUS_BLOCK_DESCENDANTS); 
   pickerOne.setWrapSelectorWheel(false);
   pickerOne.setMinValue(0);
   pickerOne.setMaxValue(pickerOneValues.length-1);
   pickerOne.setDisplayedValues(pickerOneValues);
   pickerOne.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
       @Override
       public void onValueChange(NumberPicker numberPicker, int i, int i1) {
           Log.d("VALUE", "" + i1);
           updatePickerTwoValues(i1);
       }
   });
  </code></pre>
  
  <p>This code work well only if user do a step by step spin (one spin at time), but if user do an "energic spin" updatePickerTwoValues is called multiple time in a short time.
  There's a way to intercept when picker stop spinning, so only when spin stop, i can update pickerTwo values?</p>