The url of my feed is http://android-er.blogspot.com/feeds/posts/default?alt=json.
Actually I don't know the format of blogspot json feed, I use Online JSON Viewer (http://jsonviewer.stack.hu/) to guess. This video show how:
In my example, I download and parse the json feed in AsyncTask, Only post title and url retrieved, and display as String in ListView.
Create a new class FeedItem.java
package com.blogspot.android_er.androidparsejson;
public class FeedItem {
private String title;
private String url;
FeedItem(String title, String url){
this.title = title;
this.url = url;
}
public String getTitle(){
return title;
}
public String getUrl(){
return url;
}
@Override
public String toString() {
return title + " :\n" + url;
}
}
MainActivity.java
package com.blogspot.android_er.androidparsejson;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
Button btnLoadFeed;
TextView textViewFeedUrl;
ListView listViewFeed;
List<FeedItem> listFeedItems;
ListAdapter adapterFeed;
String myFeed = "http://android-er.blogspot.com/feeds/posts/default?alt=json";
//String myFeed = "http://arduino-er.blogspot.com/feeds/posts/default?alt=json";
//String myFeed = "http://helloraspberrypi.blogspot.com/feeds/posts/default?alt=json";
//String myFeed = "http://photo-er.blogspot.com/feeds/posts/default?alt=json";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnLoadFeed = (Button)findViewById(R.id.loadfeed);
textViewFeedUrl = (TextView)findViewById(R.id.feedurl);
listViewFeed = (ListView)findViewById(R.id.listviewfeed);
listFeedItems = new ArrayList<>();
adapterFeed = new ArrayAdapter<FeedItem>(
this, android.R.layout.simple_list_item_1, listFeedItems);
listViewFeed.setAdapter(adapterFeed);
btnLoadFeed.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
textViewFeedUrl.setText(myFeed);
new JsonTask(listFeedItems, listViewFeed).execute(myFeed);
}
});
}
/*
JsonTask:
AsyncTask to download and parse JSON Feed of blogspot in background
*/
private class JsonTask extends AsyncTask<String, FeedItem, String> {
List<FeedItem> jsonTaskList;
ListView jsonTaskListView;
public JsonTask(List<FeedItem> targetList, ListView targetListView) {
super();
jsonTaskList = targetList;
jsonTaskListView = targetListView;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
jsonTaskList.clear();
jsonTaskListView.invalidateViews();
}
@Override
protected String doInBackground(String... params) {
try {
final String queryResult = sendQuery(params[0]);
parseQueryResult(queryResult);
} catch (IOException e) {
e.printStackTrace();
final String eString = e.toString();
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
eString,
Toast.LENGTH_LONG).show();
}
});
} catch (JSONException e) {
e.printStackTrace();
final String eString = e.toString();
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,
eString,
Toast.LENGTH_LONG).show();
}
});
}
return null;
}
@Override
protected void onProgressUpdate(FeedItem... values) {
FeedItem newItem = values[0];
jsonTaskList.add(newItem);
jsonTaskListView.invalidateViews();
}
private String sendQuery(String query) throws IOException {
String queryReturn = "";
URL queryURL = new URL(query);
HttpURLConnection httpURLConnection = (HttpURLConnection)queryURL.openConnection();
if(httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK){
InputStreamReader inputStreamReader =
new InputStreamReader(httpURLConnection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(
inputStreamReader, 8192);
String line = null;
while((line = bufferedReader.readLine()) != null){
queryReturn += line;
}
bufferedReader.close();
}
return queryReturn;
}
private void parseQueryResult(String json) throws JSONException {
JSONObject jsonObject = new JSONObject(json);
final JSONObject jsonObject_feed = jsonObject.getJSONObject("feed");
final JSONArray jsonArray_entry = jsonObject_feed.getJSONArray("entry");
runOnUiThread(new Runnable() {
@Override
public void run() {
if(jsonArray_entry == null){
Toast.makeText(MainActivity.this,
"jsonArray_entry == null",
Toast.LENGTH_LONG).show();
}else{
Toast.makeText(MainActivity.this,
String.valueOf(jsonArray_entry.length()),
Toast.LENGTH_LONG).show();
for(int i=0; i<jsonArray_entry.length(); i++){
try {
JSONObject thisEntry = (JSONObject) jsonArray_entry.get(i);
JSONObject thisEntryTitle = thisEntry.getJSONObject("title");
String thisEntryTitleString = thisEntryTitle.getString("$t");
JSONArray jsonArray_EntryLink = thisEntry.getJSONArray("link");
//search for the link element with rel="alternate"
//I assume it's one and only one element with rel="alternate",
//and its href hold the link to the page
for(int j=0; j<jsonArray_EntryLink.length(); j++){
JSONObject thisLink = (JSONObject) jsonArray_EntryLink.get(j);
try{
String thisLinkRel = thisLink.getString("rel");
if(thisLinkRel.equals("alternate")){
try{
String thisLinkHref = thisLink.getString("href");
FeedItem thisElement = new FeedItem(
thisEntryTitleString.toString(),
thisLinkHref);
publishProgress(thisElement);
break;
}catch (JSONException e){
//no such mapping exists
}
}
}catch (JSONException e){
//no such mapping exists
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
});
}
}
}
layout/activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
android:orientation="vertical"
tools:context="com.blogspot.android_er.androidparsejson.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<Button
android:id="@+id/loadfeed"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Load Feed"/>
<TextView
android:id="@+id/feedurl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textStyle="bold|italic"/>
<ListView
android:id="@+id/listviewfeed"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
uses-permission of "android.permission.INTERNET" is needed in AndroidManifest.xml.
Download the files .Next:
- Parse blogspot JSON feed: detect item clicked to open in browser using CustomTabsIntent
Remark@2017-05-20:
This video show how I TRY to locate the thumbnail from the JSON feed. In order to find the url of the thumbnail of the posts, you have to search "media$thumbnail" elements in the feeds. But I haven't actually implemented the code.
