android开发-hack news droid的解析

package com.glebpopov.hackernews.net;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.glebpopov.hackernews.domain.CommentItem;
import com.glebpopov.hackernews.domain.NewsContainer;
import com.glebpopov.hackernews.domain.NewsItem;

import android.util.Log;

public class DataParser
{
private String dataUrl = null;
private String TAG = "DataParser";

public DataParser(String url)
{
dataUrl = url;
}

public String getUrl()
{
return dataUrl;
}

//returns HTTP code
public int submitData()
{
if (getUrl() == null || getUrl().length() == 0)
{
Log.e(TAG, "getJsonData: invalid URL");
return 500;
}
// Create the httpclient
HttpClient httpclient = new DefaultHttpClient();

// Prepare a request object
HttpGet httpget = new HttpGet(getUrl());

// Execute the request
HttpResponse response;

try
{
// Open the webpage.
response = httpclient.execute(httpget);
return response.getStatusLine().getStatusCode();
}
catch (IOException  ex)
{
// thrown by line 80 - getContent();
// Connection was not established
Log.e(TAG, "getJsonData: Connection failed: " + ex.getMessage());
}
finally
{

}
return 500;
}

public NewsContainer getNews()
{
if (dataUrl == null || dataUrl.length() == 0)
{
Log.e(TAG, "getNews: invalid URL");
return null;
}
Log.d(TAG, "URL: " + dataUrl);

NewsContainer container = null;
JSONArray jsonData = getJsonData();
if (jsonData != null)
{
container = new NewsContainer();
ArrayList data = new ArrayList();
NewsItem item = null;
NewsItem moreLink = null;
//shouldn't return links to NEXT...links to next should be appended somewhere else
for (int i=0; i
{
try
{
if (jsonData.getJSONObject(i).getString("title") != null &&
jsonData.getJSONObject(i).getString("title").toLowerCase().equals("nextid")
)
{
moreLink = new NewsItem();
moreLink.setTitle(jsonData.getJSONObject(i).getString("title"));
moreLink.setUrl("" + jsonData.getJSONObject(i).getString("url"));

} else
{
int id = 0;
try
{
id = Integer.parseInt(jsonData.getJSONObject(i).getString("item_id"));
} catch (Exception ex) {}

item = new NewsItem();
item.setTitle(jsonData.getJSONObject(i).getString("title"));
item.setUrl(jsonData.getJSONObject(i).getString("url"));
item.setPostedDate(jsonData.getJSONObject(i).getString("time"));
item.setPoints(jsonData.getJSONObject(i).getString("score"));
item.setAuthor(jsonData.getJSONObject(i).getString("user"));
item.setComments(jsonData.getJSONObject(i).getString("comments"));
item.setId(id);

//add to container
data.add(item);
}
} catch (Exception ex)
{
Log.e(TAG, "getNews: exception while parsing JSON data: " + ex);
}
}

container.setNewsContainer(data);
container.setMoreNewsLink(moreLink);
}

if (container != null && container.getNewsContainer() != null)
{
Log.d(TAG, "getNews: returning " + container.getNewsContainer().size() + " elements");
} else
{
Log.w(TAG, "getNews: failed to retrieve news data");
}
return container;
}

public ArrayList getComments()
{
if (dataUrl == null || dataUrl.length() == 0)
{
Log.e(TAG, "getComments: invalid URL");
return null;
}
JSONArray jsonData = getJsonData();
ArrayList data = parseComments(jsonData, -1);
Log.d(TAG, "getComments: returning " + data.size() + " elements");
return data;
}

public ArrayList parseComments(JSONArray jsonData, int parentId)
{
//Log.d(TAG, "parseComments: ParentID=" + parentID);

ArrayList data = new ArrayList();
if (jsonData != null)
{
//Log.d(TAG, "parseComments: Container Count=" + jsonData.length());
CommentItem item = null;
for (int i=0; i
{
item = new CommentItem();
try
{
int id = -1;
try
{
id = Integer.parseInt(jsonData.getJSONObject(i).getString("id"));
} catch (Exception ex) {}

item.setId(id);
item.setParentId(parentId);
item.setComment(jsonData.getJSONObject(i).getString("comment"));
item.setReplyId(jsonData.getJSONObject(i).getString("reply_id"));
item.setPostedDate(jsonData.getJSONObject(i).getString("time"));
item.setAuthor(jsonData.getJSONObject(i).getString("username"));
if (jsonData.getJSONObject(i).getJSONArray("children") != null)
{
item.setChildren(parseComments(jsonData.getJSONObject(i).getJSONArray("children"), id));
}

} catch (Exception ex)
{
Log.e(TAG, "parseComments: exception while parsing JSON data: " + ex);
}
data.add(item);
}
}
return data;
}

public JSONArray getJsonData()
{
if (dataUrl == null || dataUrl.length() == 0)
{
Log.e(TAG, "getJsonData: invalid URL");
return null;
}
// Create the httpclient
HttpClient httpclient = new DefaultHttpClient();

// Prepare a request object
HttpGet httpget = new HttpGet(dataUrl);

// Execute the request
HttpResponse response;

try {

// return string
String returnString = null;

// Open the webpage.
response = httpclient.execute(httpget);

if(response.getStatusLine().getStatusCode() == 200){
// Connection was established. Get the content.

HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to worry about connection release



if (entity != null) {
// A Simple JSON Response Read
InputStream instream = entity.getContent();

returnString = convertStreamToString(instream);

//Log.d(TAG, "Return String: " + returnString);

// Load the requested page converted to a string into a JSONObject.
JSONObject myAwway = new JSONObject(returnString);

// Get the query value'
//String query = myAwway.getString("query");

// Make array of the suggestions
JSONArray recs = myAwway.getJSONArray("items");
if (recs != null)
{
Log.d(TAG, "getJsonData: Got JSON Data: " + recs.length());
} else
{
Log.w(TAG, "getJsonData: no data returned");
}
// Cose the stream.
instream.close();
return recs;

}

}
else {
// code here for a response othet than 200.  A response 200 means the webpage was ok
// Other codes include 404 - not found, 301 - redirect etc...
// Display the response line.
Log.e(TAG, "getJsonData: Unable to load page. Status: " + response.getStatusLine());
}
}
catch (IOException  ex) {
// thrown by line 80 - getContent();
// Connection was not established
Log.e(TAG, "getJsonData: Connection failed: " + ex.getMessage());
}
catch (JSONException ex){
// JSON errors
Log.e(TAG, "getJsonData: JSONException: " + ex.getMessage());
} finally
{

}
return null;
}

public String convertStreamToString(InputStream is) {
/*
* To convert the InputStream to String we use the BufferedReader.readLine()
* method. We iterate until the BufferedReader return null which means
* there's no more data to read. Each line will appended to a StringBuilder
* and returned as String.
*/
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();

String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}

public NewsItem getLatestNews() {
Log.d(TAG, "getLatestNews");
NewsContainer container = getNews();
if (container != null)
{
ArrayList data = container.getNewsContainer();
if (data != null && data.size() > 0 && data.get(0) != null && data.get(0).getTitle() != null)
{
Log.d(TAG, "getLatestNews: successfully retrieved " + data.size() + " records");
return data.get(0);
}
}
Log.w(TAG, "getLatestNews: no data returned");
return null;
}
}