ListView不同的项目布局(item layout)的实现

如果我们有这样的需求：每隔几个数据项出现一个分隔项。如图：



你需要做这些:

重写Adapter的getViewTypeCount() – 返回你有多少个不同的布局
重写Adapter的getItemViewType(int) – 由position返回view type id
根据view item的类型，在getView中创建正确的convertView

public class MultipleItemsList extends ListActivity {
private MyCustomAdapter mAdapter;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mAdapter = new MyCustomAdapter();
for (int i = 1; i < 50; i++) {
mAdapter.addItem("item " + i);
if (i % 4 == 0) {
mAdapter.addSeparatorItem("separator " + i);
}
}
setListAdapter(mAdapter);
}

private class MyCustomAdapter extends BaseAdapter {

private static final int TYPE_ITEM = 0;
private static final int TYPE_SEPARATOR = 1;
private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;

private ArrayList mData = new ArrayList();
private LayoutInflater mInflater;

private TreeSet mSeparatorsSet = new TreeSet();

public MyCustomAdapter() {
mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public void addItem(final String item) {
mData.add(item);
notifyDataSetChanged();
}

public void addSeparatorItem(final String item) {
mData.add(item);
// save separator position
mSeparatorsSet.add(mData.size() - 1);
notifyDataSetChanged();
}

@Override
public int getItemViewType(int position) {
return mSeparatorsSet.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
}

@Override
public int getViewTypeCount() {
return TYPE_MAX_COUNT;
}

@Override
public int getCount() {
return mData.size();
}

@Override
public String getItem(int position) {
return mData.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
int type = getItemViewType(position);
System.out.println("getView " + position + " " + convertView + " type = " + type);
if (convertView == null) {
holder = new ViewHolder();
switch (type) {
case TYPE_ITEM:
convertView = mInflater.inflate(R.layout.item1, null);
holder.textView = (TextView)convertView.findViewById(R.id.text);
break;
case TYPE_SEPARATOR:
convertView = mInflater.inflate(R.layout.item2, null);
holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
break;
}
convertView.setTag(holder);
} else {
holder = (ViewHolder)convertView.getTag();
}
holder.textView.setText(mData.get(position));
return convertView;
}

}

public static class ViewHolder {
public TextView textView;
}
}