Json手动解析小案例

淩亂°似流年 2022-08-19 09:01 136阅读 0赞

本文Json解析荔枝新闻  
json格式为：

{
        "status":"ok",
        "paramz":{
            "feeds":[
                {
                    "id":299080,
                    "oid":288342,
                    "category":"article",
                    "data":{
                        "subject":"视频直播：AB会面",
                        "summary":"在新加坡会面",
                        "cover":"/Attachs/Article/288342/56a263bcab4a4c55b0bef0528ce880b6_padmini.JPG",
                        "pic":"",
                        "format":"video",
                        "changed":"2015-11-07 14:35:22"
                    }
                },
                {
                    "id":299076,
                    "oid":288340,
                    "category":"article",
                    "data":{
                        "subject":"荔枝新闻3.0：不止是阅读",
                        "summary":"江苏广电旗下资讯类手机应用“荔枝新闻”于近期推出全新升级换代的3.0版。",
                        "cover":"/Attachs/Article/288340/3e8e2c397c70469f8845fad73aa38165_padmini.JPG",
                        "pic":"",
                        "format":"txt",
                        "changed":"2015-09-22 16:01:41"
                    }
                }
            ],
            "PageIndex":1,
            "PageSize":20,
            "TotalCount":53521,
            "TotalPage":2677
        }
    }

MainActivity中的代码：

package org.moblie.train.zday09_json;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    import org.moblie.train.zday09_json_MyUtils.HttpURLConnHelper;
    
    import android.app.Activity;
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.widget.AbsListView;
    import android.widget.AbsListView.OnScrollListener;
    import android.widget.ListView;
    import android.widget.Toast;
    
    public class MainActivity extends Activity {
    	private String jsonUrl = "http://litchiapi.jstv.com/api/GetFeeds?column=0&PageSize=20&pageIndex=";
    	private ListView listView;
    	private MyAdapter adapter;
    	private List<Map<String, String>> list = new ArrayList<Map<String, String>>();
    	private boolean isBottom;
    	private int currentPage = 1;
    
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_main);
    		// 初始化ListView
    		initViews();
    		// 完成网络请求，通过异步任务，在子线程完成
    		loadNetworkData();
    	}
    
    	private void loadNetworkData() {
    		new MyTask().execute(jsonUrl + currentPage);
    	}
    
    	private void initViews() {
    		listView = (ListView) findViewById(R.id.listView_Main);
    		adapter = new MyAdapter(list, this);
    		listView.setAdapter(adapter);
    		listView.setOnScrollListener(new OnScrollListener() {
    
    			@Override
    			public void onScrollStateChanged(AbsListView view, int scrollState) {
    				if (isBottom && scrollState == SCROLL_STATE_IDLE) {
    					// 已经滑动到最底部。此时需要将页数加1，再重新请求
    					currentPage++;
    					loadNetworkData();
    				}
    			}
    
    			@Override
    			public void onScroll(AbsListView view, int firstVisibleItem,
    					int visibleItemCount, int totalItemCount) {
    				isBottom = ((firstVisibleItem + visibleItemCount) == totalItemCount);
    			}
    		});
    	}
    
    	public List<Map<String, String>> jsonStringToList(String jsonString) {
    		try {
    			JSONObject jsonObject = new JSONObject(jsonString);
    			if (jsonObject.getString("status").equals("ok")) {
    				JSONObject jsonObject_paramz = jsonObject
    						.getJSONObject("paramz");
    				JSONArray jsonArray_feeds = jsonObject_paramz
    						.getJSONArray("feeds");
    				// 解析JSONArray要遍历
    				for (int i = 0; i < jsonArray_feeds.length(); i++) {
    					JSONObject jsonObject_feed = jsonArray_feeds
    							.getJSONObject(i);
    					JSONObject jsonObject_data = jsonObject_feed
    							.getJSONObject("data");
    					String jsonString_subject = jsonObject_data
    							.getString("subject");
    					String jsonString_summary = jsonObject_data
    							.getString("summary");
    					Map<String, String> map = new HashMap<String, String>();
    					map.put("subject", jsonString_subject);
    					map.put("summary", jsonString_summary);
    					list.add(map);
    				}
    			}
    		} catch (JSONException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    		return list;
    	}
    
    	class MyTask extends AsyncTask<String, Integer, List<Map<String, String>>> {
    
    		@Override
    		// 在子线程中完成的方法
    		protected List<Map<String, String>> doInBackground(String... params) {
    			// 网络请求返回的byte数组
    			// 参数即URL
    			/**
    [此处用到的网络请求工具类详见博客](http://blog.csdn.net/iblade/article/details/50488749)
    */
    			byte[] data = HttpURLConnHelper.loadByteFromURL(params[0]);
    			if (data != null) {
    				String jsonString = new String(data);
    				List<Map<String, String>> li = jsonStringToList(jsonString);
    				return li;
    			} else {// 如果data为空，即网络数据请求失败
    				Toast.makeText(MainActivity.this, "网络异常，请检查网络",
    						Toast.LENGTH_SHORT);
    			}
    			return null;
    		}
    
    		@Override
    		protected void onPostExecute(List<Map<String, String>> li) {
    			super.onPostExecute(li);
    			list.addAll(li);
    			adapter.notifyDataSetChanged();
    		}
    	}
    }

MyAdapter中的代码：

package org.moblie.train.zday09_json;
    
    import java.util.List;
    import java.util.Map;
    
    import android.app.Activity;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;
    
    public class MyAdapter extends BaseAdapter {
    	private List<Map<String, String>> list;
    	private Activity activity;
    
    	public MyAdapter(List<Map<String, String>> list, Activity activity) {
    		super();
    		this.list = list;
    		this.activity = activity;
    	}
    
    	@Override
    	public int getCount() {
    		return list.size();
    	}
    
    	@Override
    	public Object getItem(int position) {
    		return list.get(position);
    	}
    
    	@Override
    	public long getItemId(int position) {
    		return position;
    	}
    
    	@Override
    	public View getView(int position, View convertView, ViewGroup parent) {
    		ViewHolder holder = null;
    		if (convertView == null) {
    			holder = new ViewHolder();
    			convertView = activity.getLayoutInflater().inflate(
    					R.layout.item_listview_main, parent, false);
    			holder.subjectView = (TextView) convertView
    					.findViewById(R.id.textSuject);
    			holder.summaryView = (TextView) convertView
    					.findViewById(R.id.textSummary);
    			convertView.setTag(holder);
    		} else {
    			holder = (ViewHolder) convertView.getTag();
    		}
    		holder.subjectView.setText(list.get(position).get("subject"));
    		holder.summaryView.setText(list.get(position).get("summary"));
    
    		return convertView;
    	}
    
    	class ViewHolder {
    		private TextView subjectView;
    		private TextView summaryView;
    
    	}
    }

item\_listview\_activity.xml中的代码：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal" >
    
        <TextView
            android:id="@+id/textSuject"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="标题" />
    
        <TextView
            android:id="@+id/textSummary"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="内容" />
    
    </LinearLayout>

activity\_main.xml中代码：

我们的数据源来自网络  
所以一定不要忘了在清单文件中为其设置连接网络权限  
清单文件中的代码：

<uses-sdk
            android:minSdkVersion="8"
            android:targetSdkVersion="14" />
        <uses-permission android:name="android.permission.INTERNET"/>