类概述

BaseAdapter主要用于ListView(实现指定的ListAdapter接口)、Spinner(实现指定的SpinnerAdapter接口)以及GridView的共同实现一个公共基类适配器。

假设我们实现一个ArrayListAdapter，
public abstract class ArrayListAdapter extends BaseAdapter{

protected ArrayList mList;
protected Activity mContext;
protected ListView mListView;

public ArrayListAdapter(Activity context){
this.mContext = context;
}

@Override
//设置像layout中填充的条目数量
public int getCount() {
if(mList != null)
return mList.size();
else
return 0;
}

@Override
public Object getItem(int position) {
return mList == null null : mList.get(position);
}

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

@Override
/**
* @param position position就是位置从0开始
* @param convertView convertView是Spinner,ListView中每一项要显示的view
* @param parent parent就是父窗体了，也就是Spinner,ListView,GridView了
* @return 通常return 的view也就是convertView
* 绘制的内容均在此实现
*/
abstract public View getView(int position, View convertView, ViewGroup parent);

public void setList(ArrayList list){
this.mList = list;
notifyDataSetChanged();
}

public ArrayList getList(){
return mList;
}

public void setList(T[] list){
ArrayList arrayList = new ArrayList(list.length);
for (T t : list) {
arrayList.add(t);
}
setList(arrayList);
}

public ListView getListView(){
return mListView;
}

public void setListView(ListView listView){
mListView = listView;
}

}