Beginning Android

overriding the default getView() but otherwise allowing the delegated ListAdapter to do the “real work:”

public class RateableWrapper extends AdapterWrapper {
 Context ctxt = null;
 float[] rates = null;
 public RateableWrapper(Context ctxt, ListAdapter delegate) {
  super(delegate);
  this.ctxt = ctxt;
  this.rates = new float [delegate.getCount()];
  for(int i=0; idelegate.getCount(); i++) {
   this.rates[i]=2.0f;
  }
 }
 public View getView(int position, View convertView,
  ViewGroup parent) {
  ViewWrapper wrap = null;
  View row = convertView;
  if (convertView==null) {
   LinearLayout layout = new LinearLayout(ctxt);
   RatingBar rate = new RatingBar(ctxt);
   rate.setNumStars(3);
   rate.setStepSize(1.0f);
   View guts = delegate.getView(position, null, parent);
   layout.setOrientation(LinearLayout.HORIZONTAL);
   rate.setLayoutParams(new LinearLayout.LayoutParams(
    LinearLayout.LayoutParams.WRAP_CONTENT,
    LinearLayout.LayoutParams.FILL_PARENT));
   guts.setLayoutParams(new LinearLayout.LayoutParams(
    LinearLayout.LayoutParams.FILL_PARENT,
    LinearLayout.LayoutParams.FILL_PARENT));
   RatingBar.OnRatingBarChangeListener l =
    new RatingBar.OnRatingBarChangeListener() {
    public void onRatingChanged(RatingBar ratingBar,
     float rating, boolean fromTouch) {
     rates[(Integer)ratingBar.getTag()] = rating;
    }
   };
   rate.setOnRatingBarChangeListener(l);
   layout.addView(rate);
   layout.addView(guts);
   wrap = new ViewWrapper(layout);
   wrap.setGuts(guts);
   layout.setTag(wrap);
   rate.setTag(new Integer(position));
   rate.setRating(rates[position]);
   row = layout;
  } else {
   wrap = (ViewWrapper)convertView.getTag();
   wrap.setGuts(delegate.getView(position, wrap.getGuts(),
    parent));
   wrap.getRatingBar().setTag(new Integer(position));
   wrap.getRatingBar().setRating(rates [position]);
  }
  return(row);
 }
}

The idea is that RateableWrapper is where most of our rate-list logic resides. It puts the rating bars on the rows and it tracks the rating bars’ states as they are adjusted by the user. For the states, it has a float[] sized to fit the number of rows that the delegate says are in the list.

RateableWrapper’s implementation of getView() is reminiscent of the one from RateListDemo, except that rather than use LayoutInflater, we need to manually construct a LinearLayout to hold our RatingBar and the “guts” (that is, whatever view the delegate created that we are decorating with the checkbox). LayoutInflater is designed to construct a View from raw widgets; in our case, we don’t know in advance what the rows will look like, other than that we need to add a checkbox to them. However, the rest is similar to what we saw in RateListDemo:

class ViewWrapper {
 ViewGroup base;
 View guts = null;
 RatingBar rate = null;
 ViewWrapper(ViewGroup base) {
  this.base = base;
 }
 RatingBar getRatingBar() {
  if (rate==null) {
   rate = (RatingBar)base.getChildAt(0);
  }
  return(rate);