10. 面向holder编程、自动轮询

没有看过上一篇文章的话，建议先去阅读GooglePlay:9.代码抽取（adapter）
项目框架的搭建：
以后每个view都是holder

BaseHolder 

  1. public abstract class BaseHolder<Data>  {／／写data和t一样
	private View contentView;
	private Data data;
	protected BitmapUtils bitmapUtils;
	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);
}
MoreHolder 
  1. public class MoreHolder extends BaseHolder<Integer> {
	public static final int HAS_NO_MORE=0;  // 没有额外数据了
	public static final int LOAD_ERROR=1;// 加载失败
	public static final int HAS_MORE=2;//  有额外数据
	
	private RelativeLayout rl_more_loading,rl_more_error;
	
	/**当Holder显示的时候 显示什么样子*/
	@Override
	public View initView() {
		View view=UiUtils.inflate(R.layout.load_more);
		rl_more_loading=(RelativeLayout) view.findViewById(R.id.rl_more_loading);
		rl_more_error=(RelativeLayout) view.findViewById(R.id.rl_more_error);
		return view;
	}
	private DefaultAdapter adapter;
	
	public MoreHolder(DefaultAdapter adapter) {
		super();
		this.adapter=adapter;
		
	}
	@Override
	public View getContentView() {
		loadMore();
		
		return super.getContentView();
	}
	private void loadMore() {
		// 请求服务器   加载下一批数据 
		//  交给Adapter  让Adapter  加载更多数据
		adapter.loadMore();
	}
	/**根据数据做界面的修改*/
	@Override
	public void refreshView(Integer data) {
		rl_more_error.setVisibility(data==LOAD_ERROR?View.VISIBLE:View.GONE);
		rl_more_loading.setVisibility(data==HAS_MORE?View.VISIBLE:View.GONE);
		
	}
}
DefaultAdapter ： 多种不同类型条目的ListView 
  1. public abstract class DefaultAdapter<Data> extends BaseAdapter {
	protected List<Data> datas;
	private static final int DEFAULT_ITEM = 0;
	private static final int MORE_ITEM = 1;
	public List<Data> getDatas() {
		return datas;
	}
	public void setDatas(List<Data> datas) {
		this.datas = datas;
	}
	public DefaultAdapter(List<Data> datas) {
		this.datas = datas;
	}
	@Override
	public int getCount() {
		return datas.size() + 1; // 最后的一个条目 就是加载更多的条目
	}
	@Override
	public Object getItem(int position) {
		return datas.get(position);
	}
	/** 根据位置 判断当前条目是什么类型 */
	@Override
	public int getItemViewType(int position) {  //20     
		if (position == datas.size()) { // 当前是最后一个条目
			return MORE_ITEM;
		}
		return getInnerItemViewType(position); // 如果不是最后一个条目 返回默认类型
	}
	private int getInnerItemViewType(int position) {
		return DEFAULT_ITEM;
	}
	/** 当前ListView 有几种不同的条目类型 */
	@Override
	public int getViewTypeCount() {
		return super.getViewTypeCount() + 1; // 2 有两种不同的类型
	}
	@Override
	public long getItemId(int position) {
		return position;
	}
	public View getView(int position, View convertView, ViewGroup parent) {
		BaseHolder holder = null;
		switch (getItemViewType(position)) {  // 判断当前条目时什么类型
		case MORE_ITEM:
			if(convertView==null){
				holder=getMoreHolder();
			}else{
				holder=(BaseHolder) convertView.getTag();
			}
			break;
		case DEFAULT_ITEM:
			if (convertView == null) {
				holder = getHolder();
			} else {
				holder = (BaseHolder) convertView.getTag();
			}
			if (position < datas.size()) {
				holder.setData(datas.get(position));
			}
			break;
		}
		return holder.getContentView();  //  如果当前Holder 恰好是MoreHolder  证明MoreHOlder已经显示
	}
	private MoreHolder holder;
	private BaseHolder getMoreHolder() {
		if(holder!=null){
			return holder;
		}else{
			holder=new MoreHolder(this);
			return holder;
		}
	}
	protected abstract BaseHolder<Data> getHolder();
	
	/**
	 * 当加载更多条目显示的时候 调用该方法
	 */
	public void loadMore() {
		ThreadManager.getInstance().createLongPool().execute(new Runnable() {
			
			@Override
			public void run() {
				// 在子线程中加载更多 
				final List<Data> newData = onload();
				UiUtils.runOnUiThread(new Runnable() {
					
					@Override
					public void run() {
						if(newData==null){
							holder.setData(MoreHolder.LOAD_ERROR);//  
						}else if(newData.size()==0){
							holder.setData(MoreHolder.HAS_NO_MORE);
						}else{
							// 成功了
							holder.setData(MoreHolder.HAS_MORE);
							datas.addAll(newData);//  给listView之前的集合添加一个新的集合
							notifyDataSetChanged();// 刷新界面
						
						}
						
					}
				});
			
				
			}
		});
	}
	/**
	 * 加载更多数据
	 */
	protected  abstract List<Data> onload();
}
 
修改8的代码SubjectFragment
  1. public class SubjectFragment extends BaseFragment {
	private List<SubjectInfo> datas;
	@Override
	public View createSuccessView() {
		BaseListView  listView=new BaseListView  (UiUtils.getContext());
		listView.setAdapter(new SubjectAdapter(datas));
		return listView;
	}
	private class SubjectAdapter extends DefaultAdapter<SubjectInfo>{
		public SubjectAdapter(List<SubjectInfo> datas) {
			super(datas);
		}
		@Override
		protected BaseHolder<SubjectInfo> getHolder() {
			return new SubjectHolder();
		}
		@Override
		protected List<SubjectInfo> onload() {
			SubjectProtocol protocol=new SubjectProtocol();
			List<SubjectInfo> load = protocol.load(0);
			datas.addAll(load);
			return load;
		}
	}
	class SubjectHolder extends BaseHolder<SubjectInfo>{
		ImageView item_icon;
		TextView item_txt;
		@Override
		public View initView() {
			View contentView=UiUtils.inflate(R.layout.item_subject);
			this.item_icon=(ImageView) contentView.findViewById(R.id.item_icon);
			this.item_txt=(TextView) contentView.findViewById(R.id.item_txt);
			return contentView;
		}
		@Override
		public void refreshView(SubjectInfo data) {
			this.item_txt.setText(data.getDes());
			bitmapUtils.display(this.item_icon, HttpHelper.URL+"image?name="+data.getUrl());
		}
	}
	@Override
	protected LoadResult load() {
		SubjectProtocol protocol=new SubjectProtocol();
		datas = protocol.load(0);
		return checkData(datas);
	}
}
都是首页、APP、游戏页面很相似，所有又可以抽取
ListBaseHolder 
public class ListBaseHolder extends BaseHolder<AppInfo> {
	ImageView item_icon;
	TextView item_title,item_size,item_bottom;
	RatingBar item_rating;
	
	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();  //http://127.0.0.1:8090/image?name=app/com.youyuan.yyhl/icon.jpg
		
		// 显示图片的控件
		bitmapUtils.display(this.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;
	}
}
ListBaseAdapter 
  1. public abstract class ListBaseAdapter extends DefaultAdapter<AppInfo> {
	public ListBaseAdapter(List<AppInfo> datas) {
		super(datas);
	}
	@Override
	protected BaseHolder<AppInfo> getHolder() {
		return new ListBaseHolder();
	}
	@Override
	protected abstract List<AppInfo> onload();
	
}
GameFragment 
public class GameFragment extends BaseFragment {
	private List<AppInfo> datas;
	/**
	 * 加载成功的界面
	 */
	@Override
	public View createSuccessView() {
		BaseListView  listView=new BaseListView(UiUtils.getContext());
		listView.setAdapter(new ListBaseAdapter(datas){
			@Override
			protected List<AppInfo> onload() {
				GameProtocol protocol=new GameProtocol();
				List<AppInfo> load = protocol.load(datas.size());  //  
				datas.addAll(load);
				return load;
			}
			
		});
		return listView;
	}
	/**
	 * 请求服务器加载数据
	 */
	@Override
	protected LoadResult load() {
		GameProtocol protocol=new GameProtocol();
		datas = protocol.load(0);
		return checkData(datas);
	}
}
AppFragment 
public class AppFragment extends BaseFragment {
	private List<AppInfo> datas;
	/**
	 * 当加载成功的时候 显示的界面
	 */
	@Override
	public View createSuccessView() {
		BaseListView  listView=new BaseListView(UiUtils.getContext());
		listView.setAdapter(new ListBaseAdapter(datas){
			@Override
			protected List<AppInfo> onload() {
				AppProtocol protocol=new AppProtocol();
				List<AppInfo> load = protocol.load(0);
				datas.addAll(load);
				return load;
			}
			
		});
		return listView;
	}
	/**
	 * 请求服务器 获取服务器的数据
	 */
	protected LoadResult load() {
		AppProtocol protocol=new AppProtocol();
		datas = protocol.load(0);
		return checkData(datas); // 检查数据 有三种结果  成功, 错误,空
	}
}

　　

首页有个几张图片的展示栏，所以又是一个holder
HomePictureHolder （自动轮询）
public class HomePictureHolder extends BaseHolder<List<String>> {
	/* 当new HomePictureHolder()就会调用该方法 */
	private ViewPager viewPager;
	private List<String> datas;
	@Override
	public View initView() {
		viewPager = new ViewPager(UiUtils.getContext());
		viewPager.setLayoutParams(new AbsListView.LayoutParams(
				LayoutParams.MATCH_PARENT, UiUtils
						.getDimens(R.dimen.home_picture_height)));／／转换成dp
		return viewPager;
	}
	/* 当 holder.setData 才会调用 */
	@Override
	public void refreshView(List<String> datas) {
		this.datas = datas;
		viewPager.setAdapter(new HomeAdapter());
		viewPager.setCurrentItem(2000*datas.size());// 设置起始的位置   Integer.Max_Vlue/2，这样开始位置也能向后划了
		viewPager.setOnTouchListener(new OnTouchListener() {
			
			@Override
			public boolean onTouch(View v, MotionEvent event) {
				switch (event.getAction()) {
				case MotionEvent.ACTION_DOWN:
					runTask.stop();   
					break;
// 事件的取消，有可能按下viewpager滑动到listview上停止就不轮播了
				case MotionEvent.ACTION_CANCEL:  
				case MotionEvent.ACTION_UP:
					runTask.start();
					break;
				}
				
				return false; // viewPager 触摸事件 返回值要是false  
			}
		});
		runTask = new AuToRunTask();
		runTask.start();
	}
	boolean flag;
	private AuToRunTask runTask;
//Runnable并不是开启子线程，所以可以在主线程运行，thread才是开启线程
	public class AuToRunTask implements Runnable{
		@Override
		public void run() {
			if(flag){
				UiUtils.cancel(this);  // 取消之前
				int currentItem = viewPager.getCurrentItem();
				currentItem++;
				viewPager.setCurrentItem(currentItem);
				//  延迟执行当前的任务
				UiUtils.postDelayed(this, 2000);// 递归调用
			}
		}
		public void start(){
			if(!flag){
				UiUtils.cancel(this);  // 取消之前
				flag=true;
				UiUtils.postDelayed(this, 2000);// 递归调用
			}
		}
		public  void stop(){
			if(flag){
				flag=false;
				UiUtils.cancel(this);
			}
		}
		
	}
	
	class HomeAdapter extends PagerAdapter {
		// 当前viewPager里面有多少个条目
		LinkedList<ImageView> convertView=new LinkedList<ImageView>();
		// ArrayList
		@Override
		public int getCount() {
			return	Integer.MAX_VALUE;／／这样写条目就能一直划了
		}
		/* 判断返回的对象和 加载view对象的关系 */
		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			return arg0 == arg1;
		}
		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			ImageView view=(ImageView) object;
			convertView.add(view);// 把移除的对象 添加到缓存集合中
			container.removeView(view);
		}
		@Override
		public Object instantiateItem(ViewGroup container, int position) {
			int index=position%datas.size();／／访问网络需要这个参数
			ImageView view;
			if(convertView.size()>0){
				view=convertView.remove(0);
			}else{
				view= new ImageView(UiUtils.getContext());
			}
			bitmapUtils.display(view, HttpHelper.URL + "image?name="
					+ datas.get(index));
			container.addView(view); // 加载的view对象
			return view; // 返回的对象
		}
	}
}
 
UiUtils 添加这三个方法 
  2.   /**
	 * 延迟执行 任务
	 * @param run   任务
	 * @param time  延迟的时间
	 */
	public static void postDelayed(Runnable run, int time) {
		BaseApplication.getHandler().postDelayed(run, time); // 调用Runable里面的run方法
	}
	/**
	 * 取消任务
	 * @param auToRunTask
	 */
	public static void cancel(Runnable auToRunTask) {
		BaseApplication.getHandler().removeCallbacks(auToRunTask);
	}
	
}
这样写获取到图片高的dp
 <dimen name="home_picture_height">134dp</dimen>	
public static int getDimens(int homePictureHeight) {
		return (int) getResource().getDimension(homePictureHeight);
	}
 
HomeFragment 
public class HomeFragment extends BaseFragment {
	private List<AppInfo> datas;
	private List<String> pictures; //  顶部ViewPager 显示界面的数据
	
	// 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() {
		BaseListView listView=new BaseListView(UiUtils.getContext());
		HomePictureHolder holder=new HomePictureHolder();
		holder.setData(pictures);
		View contentView = holder.getContentView(); // 得到holder里面管理的view对象
		//contentView.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
		listView.addHeaderView(contentView); // 把holder里的view对象 添加到listView的上面
		
		
		listView.setAdapter(new ListBaseAdapter(datas,listView){
			@Override
			protected List<AppInfo> onload() {
				HomeProtocol protocol=new HomeProtocol();
				List<AppInfo> load = protocol.load(datas.size());
				datas.addAll(load);
				return load;
			}
			@Override
			public void onInnerItemClick(int position) {
				super.onInnerItemClick(position);
				Toast.makeText(getActivity(), "position:"+position, 0).show();
				AppInfo appInfo = datas.get(position);
				Intent intent=new Intent(UiUtils.getContext(), DetailActivity.class);
				intent.putExtra("packageName", appInfo.getPackageName());//将包名传到详情页，详情页访问网络用包名
				startActivity(intent);
			}
			
		});
	
		// 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;
	}
	
	public LoadResult load() {
		HomeProtocol protocol=new HomeProtocol();
		datas = protocol.load(0);  // load index 从哪个位置开始获取数据   0  20  40 60 
		pictures = protocol.getPictures();
		return checkData(datas);
	}
}
 
修改DefaultAdapter，这样传调到详情页面的时候position
已经是修改过的了，我们并不希望去点首页的图片展示
  1. 	public DefaultAdapter(List<Data> datas,ListView lv) {
		this.datas = datas;
		// 给ListView设置条目的点击事件
		lv.setOnItemClickListener(this);
		this.lv=lv;
	}
	
	// ListView 条目点击事件回调的方法
	@Override
	public void onItemClick(AdapterView<?> parent, View view, int position,
			long id) {
		//Toast.makeText(UiUtils.getContext(), "position:"+position, 0).show();
		position=position-lv.getHeaderViewsCount();// 获取到顶部条目的数量   位置去掉顶部view的数量
		onInnerItemClick(position);
	}
/**在该方法去处理条目的点击事件*/
	public void onInnerItemClick(int position) {
		
	}
 
面向holder编程
  1. 	public View createSuccessView() {
			BaseListView listView=new BaseListView(UiUtils.getContext());
			HomePictureHolder holder=new HomePictureHolder();
			holder.setData(pictures);
			View contentView = holder.getContentView(); // 得到holder里面管理的view对象
			contentView.setLayoutParams(new AbsListView.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
			listView.addHeaderView(contentView); // 把holder里的view对象 添加到listView的上面



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原文地址：https://www.cnblogs.com/sixrain/p/4972607.html