Android™

A Simple Web Crawler

See more Spider Examples

This demonstrates a very simple web crawler using the Chilkat Spider component. Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    CkSpider spider = new CkSpider();

    CkStringArray seenDomains = new CkStringArray();
    CkStringArray seedUrls = new CkStringArray();

    seenDomains.put_Unique(true);
    seedUrls.put_Unique(true);

    //  You will need to change the start URL to something else...
    seedUrls.Append("http://something.whateverYouWant.com/");

    //  Set outbound URL exclude patterns
    //  URLs matching any of these patterns will not be added to the 
    //  collection of outbound links.
    spider.AddAvoidOutboundLinkPattern("*?id=*");
    spider.AddAvoidOutboundLinkPattern("*.mypages.*");
    spider.AddAvoidOutboundLinkPattern("*.personal.*");
    spider.AddAvoidOutboundLinkPattern("*.comcast.*");
    spider.AddAvoidOutboundLinkPattern("*.aol.*");
    spider.AddAvoidOutboundLinkPattern("*~*");

    //  Use a cache so we don't have to re-fetch URLs previously fetched.
    spider.put_CacheDir("c:/spiderCache/");
    spider.put_FetchFromCache(true);
    spider.put_UpdateCache(true);

    while (seedUrls.get_Count() > 0) {

        String url = seedUrls.pop();
        spider.Initialize(url);

        //  Spider 5 URLs of this domain.
        //  but first, save the base domain in seenDomains
        String domain = spider.getUrlDomain(url);
        seenDomains.Append(spider.getBaseDomain(domain));

        int i;

        for (i = 0; i <= 4; i++) {
            success = spider.CrawlNext();
            if (success == true) {

                //  Display the URL we just crawled.
                Log.i(TAG, spider.lastUrl());

                //  If the last URL was retrieved from cache,
                //  we won't wait.  Otherwise we'll wait 1 second
                //  before fetching the next URL.
                if (spider.get_LastFromCache() != true) {
                    spider.SleepMs(1000);
                    }

                }
            else {
                //  cause the loop to exit..
                i = 999;
                }

            }

        //  Add the outbound links to seedUrls, except
        //  for the domains we've already seen.
        for (i = 0; i <= spider.get_NumOutboundLinks() - 1; i++) {

            url = spider.getOutboundLink(i);
            String domain = spider.getUrlDomain(url);
            String baseDomain = spider.getBaseDomain(domain);
            if (seenDomains.Contains(baseDomain) == false) {
                //  Don't let our list of seedUrls grow too large.
                if (seedUrls.get_Count() < 1000) {
                    seedUrls.Append(url);
                    }

                }

            }

        }


  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}