ListViewのアダプタとHolderのパッケージ

class MyAdapter extends BaseAdapter {

        private ArrayList data;

        public MyAdapter(List data){
            this.data = data;
        }
        @Override  
        public int getCount() {  
            return data.size();  
        }  
        @Override  
        public Object getItem(int position) {  
            return data.get(position);  
        }  
        @Override  
        public long getItemId(int position) {  
            return position;  
        }  
        @Override  
        public View getView(int position, View convertView, ViewGroup parent) {  
            ViewHolder holder;  
            if(convertView == null){  
                holder = new ViewHolder();  
                // 1.        
                View view = View.inflate(context, R.layout.listviewitem, null);  
                // 2.       
                holder.textView = view.findViewById(R.id.textView1);  
                // 3.   tag    
                view.setTag(holder);  
            }else{  
                holder = (ViewHolder) convertView.getTag();  
            }  
                // 4.          
            holder.textView.setText("    ");  
            return convertView;  
        }  
    }  

    static class ViewHolder {  
        TextView textView;  
    }  

public abstract class MyBaseHolder {  
    //   item      
    private View mRootView;  
    //   item     
    private T data;  

    //  new     ,       ,      ,  tag  
    public MyBaseHolder() {  
        mRootView = initView();  
        // 3.      tag  
        mRootView.setTag(this);  
    }  
    // 1.         
    // 2.       findViewById  
    public abstract View initView();  
    //   item       
    public View getRootView() {  
        return mRootView;  
    }  
    //     item     
    public void setData(T data) {  
        this.data = data;  
        refreshView(data);  
    }  
    //     item     
    public T getData() {  
        return data;  
    }  
    // 4.            
    public abstract void refreshView(T data);  
}  

public class SpecificHolder extends MyBaseHolder<String> {  

    private TextView mTextView;  

    @Override  
    public View initView() {  
        // 1.       
        View view = View.inflate(null, R.layout.item_listview, null);  
        // 2.        
        mTextView = (TextView) view.findViewById(R.id.textView1);  
        return view;  
    }  

    @Override  
    public void refreshView(String data) {  
        // 3.           
        mTextView.setText(data);  
    }  

}  

public abstract class MyBaseAdapter extends BaseAdapter {

    private ArrayList data;

    public MyBaseAdapter(ArrayList data) {
        this.data = data;
    }
    @Override
    public int getCount() {
        return data.size();
    }
    @Override
    public T getItem(int position) {
        return data.get(position);
    }
    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        MyBaseHolder baseHolder;
        if(convertView == null){
            // 1.       
            // 2.       findViewById
            // 3.      tag
            baseHolder = getHolder();
        }else{
            baseHolder = (MyBaseHolder) convertView.getTag();
        }
        // 4.         
        baseHolder.setData(getItem(position));
        return baseHolder.getRootView();
    }

    public abstract MyBaseHolder getHolder();
}

class MyAdapter extends MyBaseAdapter<String>{  

        public MyAdapter(ArrayList data) {  
            super(data);  
        }  

        @Override  
        public MyBaseHolder getHolder() {  
            return new SpecificHolder();  
        }  

    }