android 项目学习随笔十二（ListView加脚布局）

1、ListView加脚布局

头布局initHeaderView，在onTouchEvent事件中进行显示隐藏头布局切换

脚布局initFooterView，实现接口OnScrollListener，重写接口方法onScrollStateChanged onScroll 进行显示隐藏脚布局切换

添加标记isLoadingMore，是否正在加载数据，防止多次滑动重复加载数据

import java.util.ArrayList;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.os.Handler;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.text.TextUtils;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.TextView;
import android.widget.Toast;

import com.google.gson.Gson;
import com.itheima.zhsh66.NewsDetailActivity;
import com.itheima.zhsh66.R;
import com.itheima.zhsh66.base.BaseMenuDetailPager;
import com.itheima.zhsh66.domain.NewsData;
import com.itheima.zhsh66.domain.NewsData.News;
import com.itheima.zhsh66.domain.NewsData.TopNews;
import com.itheima.zhsh66.domain.NewsMenuData.NewsTabData;
import com.itheima.zhsh66.global.Constants;
import com.itheima.zhsh66.utils.CacheUtils;
import com.itheima.zhsh66.utils.PrefUtils;
import com.itheima.zhsh66.view.HorizontalScrollViewPager;
import com.itheima.zhsh66.view.RefreshListView;
import com.itheima.zhsh66.view.RefreshListView.OnRefreshListener;
import com.lidroid.xutils.BitmapUtils;
import com.lidroid.xutils.HttpUtils;
import com.lidroid.xutils.ViewUtils;
import com.lidroid.xutils.exception.HttpException;
import com.lidroid.xutils.http.ResponseInfo;
import com.lidroid.xutils.http.callback.RequestCallBack;
import com.lidroid.xutils.http.client.HttpRequest.HttpMethod;
import com.lidroid.xutils.view.annotation.ViewInject;
import com.viewpagerindicator.CirclePageIndicator;

/**
* 12个页签的页面对象
*
*/
public class TabDetailPager extends BaseMenuDetailPager {

// 页签分类的网络信息
private NewsTabData mTabData;
// 网络返回的新闻列表数据
private NewsData mNewsTabData;
// 加载新闻列表的url
private String mUrl;

// 头条新闻的网络数据
private ArrayList<TopNews> mTopNewsList;
// 头条新闻的数据适配器
private TopNewsAdapter mTopNewsAdapter;
// 新闻列表的集合
private ArrayList<News> mNewsList;
private NewsAdapter mNewsAdapter;

@ViewInject(R.id.vp_tab_detail)
private HorizontalScrollViewPager mViewPager;

@ViewInject(R.id.lv_tab_detail)
private RefreshListView lvList;

@ViewInject(R.id.indicator)
private CirclePageIndicator mIndicator;

@ViewInject(R.id.tv_title)
private TextView tvTopNewsTitle;

private String mMoreUrl;// 下一页的链接

private Handler mHandler = null;

public TabDetailPager(Activity activity, NewsTabData tabData) {
super(activity);
mTabData = tabData;
mUrl = Constants.SERVER_URL + mTabData.url;
}

@Override
public View initView() {
View view = View.inflate(mActivity, R.layout.pager_tab_detail, null);
ViewUtils.inject(this, view);

View header = View.inflate(mActivity, R.layout.list_header_topnews,
null);
ViewUtils.inject(this, header);// 必须也将头布局注入到ViewUtils

// 给listview添加头布局
lvList.addHeaderView(header);

// 设置下拉刷新监听
lvList.setOnRefreshListener(new OnRefreshListener() {

@Override
public void onRefresh() {
// 从网络加载数据
getDataFromServer();
}

@Override
public void loadMore() {
// 加载更多数据
if (mMoreUrl != null) {
System.out.println("加载下一页数据...");
getMoreDataFromServer();
} else {
lvList.onRefreshComplete(true);// 收起加载更多布局
Toast.makeText(mActivity, "没有更多数据了", Toast.LENGTH_SHORT)
.show();
}
}
});

lvList.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
System.out.println("pos:" + position);

News news = mNewsList.get(position);

// 当前点击的item的标题颜色置灰
TextView tvTitle = (TextView) view.findViewById(R.id.tv_title);
tvTitle.setTextColor(Color.GRAY);

// 将已读状态持久化到本地
// key: read_ids; value: 1324,1325,1326
String readIds = PrefUtils.getString("read_ids", "", mActivity);
if (!readIds.contains(news.id)) {// 以前没有添加过,才添加进来
readIds = readIds + news.id + ",";// 1324,1325,
PrefUtils.putString("read_ids", readIds, mActivity);
}

// 跳到详情页
Intent intent = new Intent(mActivity, NewsDetailActivity.class);
intent.putExtra("url", news.url);
mActivity.startActivity(intent);
}
});

return view;
}

@Override
public void initData() {
String cache = CacheUtils.getCache(mUrl, mActivity);
if (!TextUtils.isEmpty(cache)) {
processResult(cache, false);
}

getDataFromServer();
}

private void getDataFromServer() {
HttpUtils utils = new HttpUtils();
utils.send(HttpMethod.GET, mUrl, new RequestCallBack<String>() {

@Override
public void onSuccess(ResponseInfo<String> responseInfo) {
String result = responseInfo.result;
processResult(result, false);

System.out.println("访问网络成功!!!");
CacheUtils.setCache(mUrl, result, mActivity);

// 收起下拉刷新控件
lvList.onRefreshComplete(true);
}

@Override
public void onFailure(HttpException error, String msg) {
// 收起下拉刷新控件
lvList.onRefreshComplete(false);

error.printStackTrace();
Toast.makeText(mActivity, msg, Toast.LENGTH_SHORT).show();
}
});
}

/**
* 加载更多数据
*/
protected void getMoreDataFromServer() {
HttpUtils utils = new HttpUtils();
utils.send(HttpMethod.GET, mMoreUrl, new RequestCallBack<String>() {

@Override
public void onSuccess(ResponseInfo<String> responseInfo) {
String result = responseInfo.result;
processResult(result, true);
// 收起加载更多布局
lvList.onRefreshComplete(true);
}

@Override
public void onFailure(HttpException error, String msg) {
error.printStackTrace();
Toast.makeText(mActivity, msg, Toast.LENGTH_SHORT).show();
// 收起加载更多布局
lvList.onRefreshComplete(false);
}
});
}

protected void processResult(String result, boolean isMore) {
Gson gson = new Gson();
mNewsTabData = gson.fromJson(result, NewsData.class);

if (!TextUtils.isEmpty(mNewsTabData.data.more)) {
// 初始化下一页链接地址
mMoreUrl = Constants.SERVER_URL + mNewsTabData.data.more;
} else {
// 没有下一页了
mMoreUrl = null;
}

if (!isMore) {
// 初始化头条新闻
mTopNewsList = mNewsTabData.data.topnews;
if (mTopNewsList != null) {
mTopNewsAdapter = new TopNewsAdapter();
mViewPager.setAdapter(mTopNewsAdapter);
mIndicator.setViewPager(mViewPager);// 将指示器和viewpager绑定
mIndicator.setSnap(true);// 快照模式
mIndicator.setOnPageChangeListener(new OnPageChangeListener() {

@Override
public void onPageSelected(int position) {
//System.out.println("position:" + position);
TopNews topNews = mTopNewsList.get(position);
tvTopNewsTitle.setText(topNews.title);
}

@Override
public void onPageScrolled(int position,
float positionOffset, int positionOffsetPixels) {
}

@Override
public void onPageScrollStateChanged(int state) {
}
});

mIndicator.onPageSelected(0);// 将小圆点位置归零, 解决它会在页面销毁时仍记录上次位置的bug
tvTopNewsTitle.setText(mTopNewsList.get(0).title);// 初始化第一页标题
}

// 初始化新闻列表
mNewsList = mNewsTabData.data.news;
if (mNewsList != null) {
mNewsAdapter = new NewsAdapter();
lvList.setAdapter(mNewsAdapter);
}

if (mHandler == null) {
mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
int currentItem = mViewPager.getCurrentItem();

if (currentItem < mTopNewsList.size() - 1) {
currentItem++;
} else {
currentItem = 0;
}

mViewPager.setCurrentItem(currentItem);

mHandler.sendEmptyMessageDelayed(0, 2000);
};
};

// 延时2秒切换广告条
mHandler.sendEmptyMessageDelayed(0, 2000);

mViewPager.setOnTouchListener(new OnTouchListener() {

@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
System.out.println("ACTION_DOWN");
// 删除所有消息
mHandler.removeCallbacksAndMessages(null);
break;
case MotionEvent.ACTION_CANCEL:// 事件取消(当按下后,然后移动下拉刷新,导致抬起后无法响应ACTION_UP,
// 但此时会响应ACTION_CANCEL,也需要继续播放轮播条)
case MotionEvent.ACTION_UP:
// 延时2秒切换广告条
mHandler.sendEmptyMessageDelayed(0, 2000);
break;
default:
break;
}
return false;
}
});
}
} else {
// 加载更多
ArrayList<News> moreData = mNewsTabData.data.news;
mNewsList.addAll(moreData);// 追加数据
mNewsAdapter.notifyDataSetChanged();// 刷新listview
}
}

class TopNewsAdapter extends PagerAdapter {

BitmapUtils mBitmapUtils;

public TopNewsAdapter() {
// 初始化xutils中的加载图片的工具
mBitmapUtils = new BitmapUtils(mActivity);
// 设置默认加载图片
mBitmapUtils
.configDefaultLoadingImage(R.drawable.topnews_item_default);
}

@Override
public int getCount() {
return mTopNewsList.size();
}

@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
ImageView view = new ImageView(mActivity);
view.setScaleType(ScaleType.FIT_XY);// 设置图片填充效果, 表示填充父窗体
// 获取图片链接, 使用链接下载图片, 将图片设置给ImageView, 考虑内存溢出问题, 图片本地缓存
mBitmapUtils.display(view, mTopNewsList.get(position).topimage);
container.addView(view);
return view;
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}

}

class NewsAdapter extends BaseAdapter {

public BitmapUtils mBitmapUtils;

public NewsAdapter() {
mBitmapUtils = new BitmapUtils(mActivity);
mBitmapUtils
.configDefaultLoadingImage(R.drawable.pic_item_list_default);
}

@Override
public int getCount() {
return mNewsList.size();
}

@Override
public News getItem(int position) {
return mNewsList.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) {
convertView = View.inflate(mActivity, R.layout.list_item_news,
null);
holder = new ViewHolder();
holder.tvTitle = (TextView) convertView
.findViewById(R.id.tv_title);
holder.tvDate = (TextView) convertView
.findViewById(R.id.tv_date);
holder.ivIcon = (ImageView) convertView
.findViewById(R.id.iv_icon);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}

News news = getItem(position);
holder.tvTitle.setText(news.title);
holder.tvDate.setText(news.pubdate);

mBitmapUtils.display(holder.ivIcon, news.listimage);

// 标记已读和未读
String readIds = PrefUtils.getString("read_ids", "", mActivity);
if (readIds.contains(news.id)) {
// 已读
holder.tvTitle.setTextColor(Color.GRAY);
} else {
// 未读
holder.tvTitle.setTextColor(Color.BLACK);
}

return convertView;
}

}

static class ViewHolder {
public TextView tvTitle;
public TextView tvDate;
public ImageView ivIcon;
}

}

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