201.m1-优化抽取Adapter二之抽取ViewHolder

最新推荐文章于 2025-06-21 18:10:00 发布

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本文介绍了一种通用ViewHolder的设计方法，通过抽象基类BaseHolder实现了ViewHolder的共性抽取，减少了代码重复并提高了复用性。适用于不同类型的列表项。

注意到刚才的几个ViewHolder很多都是类似的，因此ViewHolder也可以抽取出来单独抽到BaseHolder，继承BaseHolder即可

BaseHolder.java

package com.ldw.market.holder;

import android.view.View;

import com.ldw.market.utils.BitmapHelper;
import com.lidroid.xutils.BitmapUtils;

/*
 * ViewHolder共性的抽取
 */
public abstract class BaseHolder<Data>  {
	private View contentView;
	private Data data;
	protected BitmapUtils bitmapUtils;
	//构造方法
	public BaseHolder(){
		bitmapUtils = BitmapHelper.getBitmapUtils();
		contentView=initView();
		contentView.setTag(this);
	}
	/** 创建界面*/
	public  abstract View initView();
	
	public View getContentView() {
		return contentView;
	}
	public void setData(Data data){
		this.data=data;
		refreshView(data);
	}
	/** 根据数据刷新界面*/
	public abstract void refreshView(Data data);
}

抽取以后的HomeFragment.java

package com.ldw.market.fragment;

import java.util.List;

import android.os.Bundle;
import android.text.format.Formatter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.RatingBar;
import android.widget.TextView;

import com.ldw.market.R;
import com.ldw.market.Adapter.DefaultAdapter;
import com.ldw.market.domain.AppInfo;
import com.ldw.market.holder.BaseHolder;
import com.ldw.market.http.HttpHelper;
import com.ldw.market.protocol.HomeProtocal;
import com.ldw.market.utils.UiUtils;
import com.ldw.market.utils.BitmapHelper;
import com.ldw.market.view.BaseListView;
import com.lidroid.xutils.BitmapUtils;
import com.lidroid.xutils.bitmap.PauseOnScrollListener;

/*
 * Home页面，主体的加载的几个页面和服务器请求数据都是在BaseFragment中去实现
 */
public class HomeFragment extends BaseFragment {

	private List<AppInfo> appInfos;

		// 当Fragment挂载的activity创建的时候调用
		@Override
		public void onActivityCreated(Bundle savedInstanceState) {
			super.onActivityCreated(savedInstanceState);
			show();
		}
	
	public View createSuccessView() {
		//使用自定义的ListView,ListView初始化的时候会初始化几个方法
		BaseListView listView = new BaseListView(UiUtils.getContext());
		
		listView.setAdapter(new HomeAdapter(appInfos));
		// 第二个参数 慢慢滑动的时候是否加载图片 false  加载   true 不加载
		//  第三个参数  飞速滑动的时候是否加载图片  true 不加载 
		listView.setOnScrollListener(new PauseOnScrollListener(bitmapUtils, false, true));
		bitmapUtils.configDefaultLoadingImage(R.drawable.ic_default);  // 设置如果图片加载中显示的图片
        bitmapUtils.configDefaultLoadFailedImage(R.drawable.ic_default);// 加载失败显示的图片
		return listView;
	}
	
	private class HomeAdapter extends DefaultAdapter<AppInfo>{

		//构造函数，初始化数据
		public HomeAdapter(List<AppInfo> appInfos) {
			super(appInfos);
			// TODO Auto-generated constructor stub
		}

		@Override
		protected BaseHolder<AppInfo> getHolder() {
			// TODO Auto-generated method stub
			return new ViewHolder();
		}

		
		
	}
	
	static class ViewHolder extends BaseHolder<AppInfo>{
		ImageView item_icon;
		TextView item_title,item_size,item_bottom;
		RatingBar item_rating;

		
		//更新界面
		@Override
		public void refreshView(AppInfo data){
			this.item_title.setText(data.getName());// 设置应用程序的名字
			String size = Formatter.formatFileSize(UiUtils.getContext(), data.getSize());
			this.item_size.setText(size);
			this.item_bottom.setText(data.getDes());
			float stars = data.getStars();
			this.item_rating.setRating(stars); // 设置ratingBar的值
			String iconUrl = data.getIconUrl(); //这个地址不全，需要加上apache地址"iconUrl": "app/com.youyuan.yyhl/icon.jpg",
			//http://127.0.0.1:8090/image?name=app/com.youyuan.yyhl/icon.jpg
			
			
			//第一个参数是显示图片的控件，第二个参数是显示图片的url
			bitmapUtils.display(this.item_icon, HttpHelper.URL+"image?name="+iconUrl);
			// 显示图片的控件
			//bitmapUtils.display(holder.item_icon, HttpHelper.URL+"image?name="+iconUrl);
		}

		@Override
		public View initView() {
			View contentView = View.inflate(UiUtils.getContext(), R.layout.item_app, null);
			this.item_icon = (ImageView) contentView.findViewById(R.id.item_icon);
			this.item_title = (TextView) contentView.findViewById(R.id.item_title);
			this.item_size = (TextView) contentView.findViewById(R.id.item_size);
			this.item_bottom = (TextView) contentView.findViewById(R.id.item_bottom);
			this.item_rating = (RatingBar) contentView.findViewById(R.id.item_rating);
			return contentView;
		}

	}

	@Override
	public LoadResult load() {
		HomeProtocal protocol = new HomeProtocal();
		appInfos = protocol.load(0);
		return checkData(appInfos);
	}
	

	
	
}

抽取以后的SubjectFragment.java

package com.ldw.market.fragment;

import java.util.List;

import com.ldw.market.R;
import com.ldw.market.Adapter.DefaultAdapter;
import com.ldw.market.domain.SubjectInfo;
import com.ldw.market.fragment.BaseFragment.LoadResult;
import com.ldw.market.holder.BaseHolder;
import com.ldw.market.http.HttpHelper;
import com.ldw.market.protocol.SubjectProtocol;
import com.ldw.market.utils.BitmapHelper;
import com.ldw.market.utils.UiUtils;
import com.lidroid.xutils.BitmapUtils;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class SubjectFragment extends BaseFragment {

	private List<SubjectInfo> datas;
	@Override
	public View createSuccessView() {
		ListView listView=new ListView(UiUtils.getContext());
		listView.setAdapter(new SubjectAdapter(datas));
		return listView;
	}
	
	private class SubjectAdapter extends DefaultAdapter<SubjectInfo>{


		//构造函数，初始化数据
		public SubjectAdapter(List<SubjectInfo> datas) {
			super(datas);
			// TODO Auto-generated constructor stub
		}

		@Override
		protected BaseHolder<SubjectInfo> getHolder() {
			return new ViewHolder();
		}
		
	}
	
	class ViewHolder extends BaseHolder<SubjectInfo>{
		ImageView item_icon;
		TextView item_txt;
		
		//更新界面
		@Override
		public void refreshView(SubjectInfo data){
			this.item_txt.setText(data.getDes());
			bitmapUtils.display(this.item_icon, HttpHelper.URL+"image?name="+data.getUrl());
		}

		@Override
		public View initView() {
			View contentView=View.inflate(UiUtils.getContext(), R.layout.item_subject, null);
			this.item_icon=(ImageView) contentView.findViewById(R.id.item_icon);
			this.item_txt=(TextView) contentView.findViewById(R.id.item_txt);
			return contentView;
		}

	}

	@Override
	protected LoadResult load() {
		SubjectProtocol protocol=new SubjectProtocol();
		datas = protocol.load(0);
		return checkData(datas);
	}

}

DefaultAdapter.java共性的Adapter

package com.ldw.market.Adapter;

import java.util.List;

import com.ldw.market.domain.AppInfo;
import com.ldw.market.holder.BaseHolder;

import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

/*
 * BaseAdapter的共性方法的封装,使用泛型封装
 */
public abstract class DefaultAdapter<Data> extends BaseAdapter{
	protected List<Data> datas;
	
	//get方法
	public List<Data> getDatas() {
		return datas;
	}

	//set方法
	public void setDatas(List<Data> datas) {
		this.datas = datas;
	}
	
	//构造函数，初始化数据
	public DefaultAdapter(List<Data> datas) {
		this.datas = datas;
	}

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return datas.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return datas.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		//BaseHolder使用泛型以支持多种数据类型的Holder
		BaseHolder<Data> holder;
		if(convertView == null){
			//每一个栏目的holder不一样
			holder = getHolder();
		}else{
			holder = (BaseHolder) convertView.getTag();
		}
		
		Data data = datas.get(position);
		holder.setData(data);
		return holder.getContentView();
	}

	protected abstract BaseHolder<Data> getHolder();

}

BaseHolder.java共性的ViewHolder，需要注意的是每一个项目的ViewHolder是不一样的，因此让子类去返回Holder，使用抽象的方法getHolder来获取子类的ViewHolder();

package com.ldw.market.Adapter;

import java.util.List;

import com.ldw.market.domain.AppInfo;
import com.ldw.market.holder.BaseHolder;

import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

/*
 * BaseAdapter的共性方法的封装,使用泛型封装
 */
public abstract class DefaultAdapter<Data> extends BaseAdapter{
	protected List<Data> datas;
	
	//get方法
	public List<Data> getDatas() {
		return datas;
	}

	//set方法
	public void setDatas(List<Data> datas) {
		this.datas = datas;
	}
	
	//构造函数，初始化数据
	public DefaultAdapter(List<Data> datas) {
		this.datas = datas;
	}

	@Override
	public int getCount() {
		// TODO Auto-generated method stub
		return datas.size();
	}

	@Override
	public Object getItem(int position) {
		// TODO Auto-generated method stub
		return datas.get(position);
	}

	@Override
	public long getItemId(int position) {
		// TODO Auto-generated method stub
		return position;
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		//BaseHolder使用泛型以支持多种数据类型的Holder
		BaseHolder<Data> holder;
		if(convertView == null){
			//每一个栏目的holder不一样,因此让子类去实现，让每一个子类返回自己的ViewHolder来获取到子类的Holder
			holder = getHolder();
		}else{
			holder = (BaseHolder) convertView.getTag();
		}
		
		Data data = datas.get(position);
		holder.setData(data);
		return holder.getContentView();
	}

	protected abstract BaseHolder<Data> getHolder();

}