Mark Murphy - Beginning Android

}

publiclong getItemId(int position) {

return(delegate. getItemId(position));

}

publicView getView(int position, View convertView,

ViewGroup parent) {

return(delegate. getView(position, convertView, parent));

}

publicvoid registerDataSetObserver(DataSetObserver observer) {

delegate. registerDataSetObserver(observer);

}

publicboolean hasStableIds() {

return(delegate. hasStableIds());

}

publicboolean isEmpty() {

return(delegate. isEmpty());

}

publicint getViewTypeCount() {

return(delegate. getViewTypeCount());

}

publicint getItemViewType(int position) {

return(delegate. getItemViewType(position));

}

publicvoid unregisterDataSetObserver(DataSetObserver observer) {

delegate. unregisterDataSetObserver(observer);

}

publicboolean areAllItemsEnabled() {

return(delegate. areAllItemsEnabled());

}

publicboolean isEnabled(int position) {

return(delegate. isEnabled(position));

}

}

We can then subclass AdapterWrapperto create RateableWrapper, overriding the default getView()but otherwise allowing the delegated ListAdapterto do the “real work:”

public classRateableWrapper extendsAdapterWrapper {

Context ctxt = null;

float[] rates = null;

public RateableWrapper(Context ctxt, ListAdapter delegate) {

super(delegate);

this.ctxt = ctxt;

this.rates = newfloat[delegate. getCount()];

for(int i=0; idelegate. getCount(); i++) {

this.rates[i]=2.0f;

}

}

publicView 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( newLinearLayout. LayoutParams(

LinearLayout.LayoutParams.WRAP_CONTENT,

LinearLayout.LayoutParams.FILL_PARENT));

guts. setLayoutParams( newLinearLayout. LayoutParams(

LinearLayout.LayoutParams.FILL_PARENT,

LinearLayout.LayoutParams.FILL_PARENT));

RatingBar.OnRatingBarChangeListener l =

newRatingBar. OnRatingBarChangeListener() {

publicvoid 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 RateableWrapperis 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 LinearLayoutto hold our RatingBarand the “guts” (that is, whatever view the delegate created that we are decorating with the checkbox). LayoutInflateris designed to construct a Viewfrom 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:

classViewWrapper {

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);

}

void setRatingBar(RatingBar rate) {

this.rate = rate;

}

View getGuts() {

if(guts== null) {

guts = base. getChildAt(1);

}