android 项目学习随笔九（ListView加头布局）

1、缓冲背景色

<ListView
android:id="@+id/lv_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="@null"
android:layout_marginTop="60dp"
android:cacheColorHint="#fff"
/>

2、给ListView添加头布局

a、头布局文件

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="vertical" >

    <FrameLayout

        android:layout_width="match_parent"

        android:layout_height="180dp" >

        <com.itheima.zhsh66.view.HorizontalScrollViewPager

            android:id="@+id/vp_tab_detail"

            android:layout_width="match_parent"

            android:layout_height="match_parent" />

        <RelativeLayout

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:layout_gravity="bottom"

            android:background="#a000"

            android:padding="5dp" >

            <TextView

                android:id="@+id/tv_title"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:text="标题"

                android:textColor="#fff"

                android:textSize="18sp" />

            <com.viewpagerindicator.CirclePageIndicator

                android:id="@+id/indicator"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content"

                android:layout_alignParentRight="true"

                android:padding="10dip"

                app:fillColor="#f00"

                app:pageColor="#9e9e9e"

                app:radius="3dp"

                app:strokeWidth="0dp" />

        </RelativeLayout>

    </FrameLayout>

</LinearLayout>

b、添加头布局

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);

import java.util.ArrayList;

import android.app.Activity;

import android.support.v4.view.PagerAdapter;

import android.support.v4.view.ViewPager.OnPageChangeListener;

import android.text.TextUtils;

import android.view.View;

import android.view.ViewGroup;

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.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.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;

    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();

            }

        });

        return view;

    }

    @Override

    public void initData() {

        String cache = CacheUtils.getCache(mUrl, mActivity);

        if (!TextUtils.isEmpty(cache)) {

            processResult(cache);

        }

        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);

                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();

            }

        });

    }

    protected void processResult(String result) {

        Gson gson = new Gson();

        mNewsTabData = gson.fromJson(result, NewsData.class);

        // 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);

        }

    }

    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);

            return convertView;

        }

    }

    static class ViewHolder {

        public TextView tvTitle;

        public TextView tvDate;

        public ImageView ivIcon;

    }

}