BaseAdapter的简单封装

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继承BaseAdapter的抽象类（根据需求进行添加方法）

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public abstract class MyBaseAdapter<T> extends BaseAdapter{

public List<T> list;

public Context context;

public MyBaseAdapter(Context context,List<T> list) {

this.list = list;

this.context = context;

}

@Override

public int getCount() {

return list != null ? list.size() : 0;

}

@Override

public Object getItem(int position) {

return list.get(position);

}

@Override

public long getItemId(int position) {

return position;

}

/**

*入口,第一步

*/

@Override

public View getView(int position, View convertView, ViewGroup parent) {

//实现抽象方法创建ViewHolder，并返回ViewHolder执行getItemView方法返回的视图

return createViewHoler(position, convertView, parent).getItemView();

}

/**

* 创建ViewHolder的抽象方法

* @param position

* @param convertView

* @param parent

* @return

*/

public abstract ViewHolder createViewHoler(int position, View convertView, ViewGroup parent);

/**

* ViewHolder类

*/

public static class ViewHolder {

private View convertView;

//保存View的map

private HashMap<Integer, View> views;

private Context context;

/**

*第四步：ViewHolder的私有构造器

*/

private ViewHolder(Context context, View convertView) {

this.convertView = convertView;

this.views = new HashMap<>();

this.context = context;

//设置tag

convertView.setTag(this);

}

/**

*第三步：提供给外界获取ViewHolder的方法（使用优化重用布局）

*/

public static ViewHolder getHolder(View convertView, Context context, int layoutId, ViewGroup parent) {

if (convertView == null) {

LayoutInflater inflater = LayoutInflater.from(context);

convertView = inflater.inflate(layoutId, parent, false);

return new ViewHolder(context, convertView);

} else {

return (ViewHolder) convertView.getTag();

}

/**

* findById方法

* @param id

* @param <T>

* @return

*/

public <T extends View> T findById(int id) {

View view = views.get(id);

if (view == null) {

view = convertView.findViewById(id);

views.put(id, view);

} else {

view = views.get(id);

}

return (T) view;

}

/**

* 设置TextView文本方法

* @param id

* @param txt

*/

public void setText(int id, String txt) {

TextView tv = findById(id);

tv.setText(txt);

}

/**

* 返回整个视图

* @return

*/

public View getItemView() {

return convertView;

}

继承封装的适配器代码

public class TestAdapter extends MyBaseAdapter{

private List<String> list;

protected Context context;

public TestAdapter(Context context, List<String> list) {

super(context, list);

this.list = list;

this.context = context;

}

/**

* 第二步

* @param position

* @param convertView

* @param parent

* @return

*/

@Override

public ViewHolder createViewHoler(int position, View convertView, ViewGroup parent) {

ViewHolder holder = ViewHolder.getHolder(convertView,context, R.layout.simple_fragment,parent);

//findById方法

TextView tv = holder.findById(R.id.tv_sp_fm);

//设置TextView文本方法

holder.setText(R.id.tv_sp_fm,list.get(position));

return holder;

}

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