安卓日记——手把手教你做知乎日报

众所周知知乎日报的api是公开的,所以我就想做个自己的知乎日报来玩一下

安卓日记——手把手教你做知乎日报_第1张图片
主页

安卓日记——手把手教你做知乎日报_第2张图片
详细页面

主要用到下列库

  • rxandroid:1.1.0

  • rxjava:1.1.3

  • retrofit:2.0.0-beta1

  • retrofit:adapter-rxjava:2.0.0-beta2

  • retrofit:converter-gson:2.0.0-beta2

  • pagerslidingtabstrip:1.0.1

  • glide:3.5.2

  • 如果不熟悉rxjava怎么用的话可以先到这里看一下(我这次只用到map)http://blog.csdn.net/lzyzsd/article/details/41833541/

  • 如果不熟悉retrofit怎么用的话可以先到这里看一下(我这次只用到Get和Path)http://www.tuicool.com/articles/fQju2uQ

  • 如果不熟悉pagerslidingtabstrip怎么用的话可以先到这里看一下http://blog.csdn.net/qq_32198277/article/details/51503156

首先要看一下知乎日报的api

我这次主要用到了几个获取今日日报无聊日报互联网安全体育日报每个新闻的详细信息的api

因为这个api返回的是json数据,推荐http://www.bejson.com/json2javapojo/
可将json转换为java类,但是有些只是字符串(生成后有些类是空白的)它都设为一个类,复制到自己java文件时,可以把不要那个类,改为String类型

带着大家简单分析一下api
以最新消息为例

最新消息

  • URL: http://news-at.zhihu.com/api/4/news/latest

  • 响应实例:

      {
          date: "20140523",
          stories: [
              {
                  title: "中国古代家具发展到今天有两个高峰,一个两宋一个明末(多图)",
                  ga_prefix: "052321",
                  images: [
                      "http://p1.zhimg.com/45/b9/45b9f057fc1957ed2c946814342c0f02.jpg"
                  ],
                  type: 0,
                  id: 3930445
              },
          ...
          ],
          top_stories: [
              {
                  title: "商场和很多人家里,竹制家具越来越多(多图)",
                  image: "http://p2.zhimg.com/9a/15/9a1570bb9e5fa53ae9fb9269a56ee019.jpg",
                  ga_prefix: "052315",
                  type: 0,
                  id: 3930883
              },
          ...
          ]
      }
    
  • 分析:

    • date : 日期
    • stories : 当日新闻
      • title : 新闻标题
      • images : 图像地址(官方 API 使用数组形式。目前暂未有使用多张图片的情形出现,曾见无 images 属性的情况,请在使用中注意 )
      • ga_prefix : 供 Google Analytics 使用
      • type : 作用未知
      • id : urlshare_url 中最后的数字(应为内容的 id)
      • multipic : 消息是否包含多张图片(仅出现在包含多图的新闻中)
    • top_stories : 界面顶部 ViewPager 滚动显示的显示内容(子项格式同上)

我们只关注story所以新建一个类时只需新建一个类是只需有一个stories的ArrayList

并生成他的getter和setter

public class RootEntity {
    private ArrayList stories ;
    public void setStories(ArrayList stories){
        this.stories = stories;
    }
    public ArrayList getStories(){
        return this.stories;
    }
}

stories我们也只关注id,title和images(images是一个ArrayList但我们只需显示第一个就好了,但有时是空的,使用时要记得判空),新建类时可以这样新建

public class StoriesEntity {
    private int id;
    private String title;
    private List images;

    public void setId(int id) {
        this.id = id;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public void setImages(List images) {
        this.images = images;
    }

    public int getId() {
        return id;
    }

    public String getTitle() {
        return title;
    }

    public List getImages() {
        return images;
    }



}

我们可以根据stories的id获取到他的详细信息,在详细信息中我们只关注body,iamge,image_source和title,生成如下类

public class StoryDetailsEntity {
    private String body;
    private String image_source;
    private String title;
    private String image;

    public void setBody(String body) {
        this.body = body;
    }

    public void setImage_source(String image_source) {
        this.image_source = image_source;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public void setImage(String image) {
        this.image = image;
    }

    public String getBody() {
        return body;
    }

    public String getImage_source() {
        return image_source;
    }

    public String getTitle() {
        return title;
    }

    public String getImage() {
        return image;
    }

}

然后到界面设计,主页是一个ViewPagerPagerSlidingTabStrip,前面已经放了使用教程,我就不详细展开了

然后每个Fragment都只有一个ListView
实现的内容都差不多,所以我们用一个BaseFragment

public class BaseFragment extends Fragment {

    private String baseUrl="http://news-at.zhihu.com";//baseUrl一定要设为这个
    public ZhiHuService service;//要靠他来获取消息,子Fragment都要用

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        service=getService();
        return inflater.inflate(R.layout.fragment_base, container, false);
    }

    
    public ZhiHuService getService() {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
        service=retrofit.create(ZhiHuService.class);
        return service;
    }

    public void loadDataSetLis(Observable rootEntityObservable, final ListView listView){
        rootEntityObservable.observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .map(new Func1>() {
                    @Override
                    public ArrayList call(RootEntity rootEntity) {
                        return rootEntity.getStories();
                    }
                })
                .subscribe(new Subscriber>() {
                    @Override
                    public void onCompleted() {

                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onNext(final ArrayList storiesEntities) {
                        listView.setAdapter(new NewsAdapter(storiesEntities,getContext()));
                        //点击item跳转到详细页面
                        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                            @Override
                            public void onItemClick(AdapterView parent, View view, int position, long id) {
                                Intent intent=new Intent(getActivity(),StoryDetailActivity.class);
                                intent.putExtra("id",storiesEntities.get(position).getId());
                                startActivity(intent);
                            }
                        });
                    }
                });
    }
}

其他Fragment都继承自这个BaseFragment,以最新消息为例

public class InterestFragment extends BaseFragment {
    private ListView lv;
    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        lv= (ListView) view.findViewById(R.id.lvnews);
        loadDataSetLis(service.getInterest(),lv);
    }

}

每个ListView的Adapter是继承自BaseAdapter,还不会用的同学请自行百度

每个item的布局只有一个TextView和ImageView
代码如下

public class NewsAdapter extends BaseAdapter {
    private List newsList;
    private LayoutInflater mInflater;
    private Context context;
    public NewsAdapter(ArrayList newsList, Context context){
        this.newsList=newsList;
        this.context=context;
        mInflater=LayoutInflater.from(context);
    }
    @Override
    public int getCount() {
        return newsList.size();
    }

    @Override
    public Object getItem(int position) {
        return newsList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Holder holder=null;
        if (convertView==null){
            convertView=mInflater.inflate(R.layout.news_item,null);
            holder=new Holder(convertView);
            convertView.setTag(holder);
        }
        holder= (Holder) convertView.getTag();
        StoriesEntity news=newsList.get(position);
        TextView tvnews=holder.tvnews;
        ImageView ivnews=holder.ivnews;
        tvnews.setText(news.getTitle());
        //记得判空,不然后会空指针异常
        if (news.getImages()==null){
            ivnews.setVisibility(View.GONE);
        }else {
            ivnews.setVisibility(View.VISIBLE);
            //用Glide根据URL加载图片
            Glide.with(context).load(news.getImages().get(0)).into(ivnews);
        }
        return convertView;
    }

    private class Holder {
        ImageView ivnews;
        TextView tvnews;
        public  Holder(View view){
            ivnews= (ImageView) view.findViewById(R.id.ivnews);
            tvnews= (TextView) view.findViewById(R.id.tvnews);
        }
    }
}

再来看看ZhihuService是怎么写的,只是retrofit的用法,前面已经有教程了,这里用得比较简单

public interface ZhiHuService {

    //今日头条
    @GET("/api/4/news/latest")
    Observable getLatestNews();
    //互联网安全
    @GET("/api/4/theme/10")
    Observable getSafety();
    //不准无聊
    @GET("/api/4/theme/11")
    Observable getInterest();
    //体育日报
    @GET("/api/4/theme/8")
    Observable getSport();
    //传入id查看详细信息
    @GET("/api/4/news/{id}")
    Observable getNewsDetails(@Path("id") int id);

}

最后就是详细页面

详细页面只是一个webview,可里面的css来自assets,不然的话页面会很难看
还需要一个HtmlUtil来生成完成的html代码
代码如下

public class HtmlUtils {
    public static String structHtml(StoryDetailsEntity storyDetailsEntity) {
        StringBuilder sb = new StringBuilder();
        sb.append("
") .append("

") .append(storyDetailsEntity.getTitle()).append("

") .append("") .append(storyDetailsEntity.getImage_source()).append("") .append("\"\"") .append("
"); //news_content_style.css和news_header_style.css都是在assets里的 String mNewsContent = "" + "" + storyDetailsEntity.getBody().replace("
", sb.toString()); return mNewsContent; } }

接下来是详细页面的activity的代码

public class StoryDetailActivity extends AppCompatActivity {
    private WebView wv;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_story_detail);
        //左上角出现小箭头
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        wv= (WebView) findViewById(R.id.webView);
        Intent intent=getIntent();

        String baseUrl="http://news-at.zhihu.com";
        int id=intent.getIntExtra("id",0);
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();
        ZhiHuService service=retrofit.create(ZhiHuService.class);

        service.getNewsDetails(id)
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeOn(Schedulers.io())
                .map(new Func1() {
                    @Override
                    public String call(StoryDetailsEntity storyDetailsEntity) {
                        return  HtmlUtils.structHtml(storyDetailsEntity);
                    }
                })
                .subscribe(new Subscriber() {
                    @Override
                    public void onCompleted() {
                    }

                    @Override
                    public void onError(Throwable e) {
                        Log.e("error",e.toString());
                    }

                    @Override
                    public void onNext(String s) {
                        //加载asset里的css
                        wv.loadDataWithBaseURL("file:///android_asset/", s, "text/html", "UTF-8", null);
                    }
                });

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        //点击小箭头返回
        if(item.getItemId() == android.R.id.home)
        {
            finish();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

那两个css是在assets里的,我这里就不展示了,所有文件我都放在github里了

源码下载

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