Android RSS Reader – Multicategory reader, Tab Layout example

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Today we have another Android RSS Reader application’s code for you – this time our code deals with multicategories. Application displays RSS feed data from 3 channels in separate tabs. You can easily extend it to display data from any number of RSS channels you wish. When you tap on a list element it displays the article contents by opening a browser. Our application looks like this.

ITCuties – Android RSS Reader – Multicategory

In this tutorial we have combined knowledge from our previous tutorials:

• How to write Android RSS parser – All the RSS parsing functionality was taken from this tutorial
• Android AsyncTask RSS Reader – We have taken loading RSS channel data in a background thread from this tutorial
• Android Intent putExtra – How to exchange data between activities.

Project structure looks like this.

ITCuties – Android RSS Reader – Multicategory – Eclipse project structure

Here is our code.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.itcuties.multicategoryrssreader"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="16" />
    
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        
        <activity
            android:name="com.itcuties.multicategoryrssreader.RssTabsActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
        <activity android:name="com.itcuties.multicategoryrssreader.RssChannelActivity" />
        
    </application>

</manifest>

Here we configure all the application’s activities and Internet access permission.

Activity layout- activity_rss_tabs.xml

<RelativeLayout 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"
    tools:context=".RssTabsActivity" >

    <TabHost
        android:id="@android:id/tabhost"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical" >

            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" >
            </TabWidget>

            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="match_parent" >

                <LinearLayout
                    android:id="@+id/tab_art"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" >
                </LinearLayout>

                <LinearLayout
                    android:id="@+id/tab_tech"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" >
                </LinearLayout>

                <LinearLayout
                    android:id="@+id/tab_sports"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent" >
                </LinearLayout>
                
            </FrameLayout>
        </LinearLayout>
    </TabHost>

</RelativeLayout>

ITCuties – Android RSS Reader – Multicategory – activity_rss_tabs layout

This is our application’s tabs layout. The most important element here is the TabHost component which encapsulates 3 tabs.

Tab selectors – rss_tab_art.xml, rss_tab_sports.xml, rss_tab_tech.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"/>

Each tab has its selector. In our case this selectors are “empty” because our tabs don’t have icons.

Activity layout – activity_rss_channel.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <ListView
        android:id="@+id/rssChannelListView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

ITCuties – Android RSS Reader – Multicategory – activity_rss_channel layout

Here is each tab’s content layout which is a list. ListView element is used here.

Activity – RssTabsActivity

package com.itcuties.multicategoryrssreader;

import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TabHost;
import android.widget.TabHost.TabSpec;

/**
 * Main activity. It displays tabs.
 * 
 * @author itcuties
 *
 */
@SuppressWarnings("deprecation") 
// @SuppressWarnings annotation is here since we are using TabActivity which is deprecated in Android 4+
// Alternative way of constructing Tab Layout is to use ActionBar API
public class RssTabsActivity extends TabActivity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		// First, set the content view
		setContentView(R.layout.activity_rss_tabs);

		// Then get the TabHost
		TabHost tabHost = getTabHost();
		
		// Art tab
		Intent artIntent = new Intent().setClass(this, RssChannelActivity.class);
		// Set Art category RSS URL
		artIntent.putExtra("rss-url", "http://feeds.reuters.com/news/artsculture?format=xml");
		
		// The name of the art tab taken from the String resources
		String artTabName = getResources().getString(R.string.tab_art);
		TabSpec artTabSpec = tabHost.newTabSpec(artTabName)
									.setIndicator(artTabName, getResources().getDrawable(R.drawable.rss_tab_art))
									.setContent(artIntent);
		// Add art tab to the TabHost
		tabHost.addTab(artTabSpec);
	
		
		// Tech tab
		Intent techIntent = new Intent().setClass(this, RssChannelActivity.class);
		// Set Tech category RSS URL
		techIntent.putExtra("rss-url", "http://feeds.reuters.com/reuters/technologyNews?format=xml");
		
		// Tech tab name taken from the string resources
		String techTabName = getResources().getString(R.string.tab_tech);
		TabSpec techTabSpec = tabHost.newTabSpec(techTabName)
									 .setIndicator(techTabName, getResources().getDrawable(R.drawable.rss_tab_tech))
									 .setContent(techIntent);
		// Add tech tab to the TabHost
		tabHost.addTab(techTabSpec);
		
		
		// Sports tab
		Intent sportsIntent = new Intent().setClass(this, RssChannelActivity.class);
		// Set Sports category RSS URL
		sportsIntent.putExtra("rss-url", "http://feeds.reuters.com/reuters/sportsNews?format=xml");
		
		// Sports tab name - string resources
		String sportsTabName = getResources().getString(R.string.tab_sports);
		TabSpec sportsTabSpec = tabHost.newTabSpec(sportsTabName)
									   .setIndicator(sportsTabName, getResources().getDrawable(R.drawable.rss_tab_sports))
				  					   .setContent(sportsIntent);
		// Add sports tab to the TabHost
		tabHost.addTab(sportsTabSpec);
		
		
		// Set current tab to Technology
		tabHost.setCurrentTab(1);
	}

}

This code is responsible for filling in each tab’s content. This activity extends TabActivity. At the beginning of the code we set the content view to acitvity_rss_tabs layout. Then TabHost reference is obtained by calling the TabActivity.getTabHost(). Next we construct each tab’s contents. An Intent is created and String object containing RSS channel URL is being send to activity using Intent.putExtra method. Then a TabSpec object is created, where we set the content with the reference to the Intent object that was created for each tab. At the end TabSpec object is added to the tabHost variable.

The same operations take place for other tabs. At the end of the code current selected tab is set by calling TabHost.setCurrentTab method – tabs numbers start from 0.

Activity – RssChannelActivity

package com.itcuties.multicategoryrssreader;

import java.util.List;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.itcuties.multicategoryrssreader.data.RssItem;
import com.itcuties.multicategoryrssreader.listeners.ListListener;
import com.itcuties.multicategoryrssreader.util.RssReader;

/**
 * Each category tab activity.
 * @author itcuties
 *
 */
public class RssChannelActivity extends Activity {
	
	// A reference to this activity
    private RssChannelActivity local;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		setContentView(R.layout.activity_rss_channel);
		
		// Get the RSS URL that was set in the RssTabActivity
		String rssUrl = (String)getIntent().getExtras().get("rss-url");
		
		// Set reference to this activity
        local = this;
         
        GetRSSDataTask task = new GetRSSDataTask();
         
        // Start process RSS task
        task.execute(rssUrl);
		
	}
	
	/**
	 * This class downloads and parses RSS Channel feed.
	 * 
	 * @author itcuties
	 *
	 */
	private class GetRSSDataTask extends AsyncTask<String, Void, List<RssItem> > {
        @Override
        protected List<RssItem> doInBackground(String... urls) {
            try {
                // Create RSS reader
                RssReader rssReader = new RssReader(urls[0]);
             
                // Parse RSS, get items
                return rssReader.getItems();
             
            } catch (Exception e) {
                Log.e("RssChannelActivity", e.getMessage());
            }
             
            return null;
        }
         
        @Override
        protected void onPostExecute(List<RssItem> result) {
             
            // Get a ListView from the RSS Channel view
            ListView itcItems = (ListView) findViewById(R.id.rssChannelListView);
                         
            // Create a list adapter
            ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(local,android.R.layout.simple_list_item_1, result);
            // Set list adapter for the ListView
            itcItems.setAdapter(adapter);
                         
            // Set list view item click listener
            itcItems.setOnItemClickListener(new ListListener(result, local));
        }
    }
	
}

This code is explained in details in our previous tutorial – Android AsyncTask RSS Reader. Major modification here is that at the beginning of the method the RSS URL is read using getExtras method. Then RSS data is being read and parsed as in our previous tutorials.

RssReader, RssParseHandler, RssItem and ListListener classes were described in details in our previous tutorial – How to write Android RSS parser.

Download this sample code here.

Install this application from here.

This code is available on our GitHub repository as well.