Android Open Source - GoogleImageLoader Image Viewer Activity

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Back to project page GoogleImageLoader.

License

The source code is released under:

GNU General Public License

Java Source Code

package com.challenge.uber.imageloader;
//  www . j  a  v  a  2s.  c o  m
import java.util.ArrayList;
import java.util.List;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.Toast;

import com.challenge.uber.imageloader.fragments.ImageViewerFragment;
import com.challenge.uber.imageloader.parser.JSONParser;
import com.challenge.uber.imageloader.utils.Utils;

/**
 * Activity for viewing and swiping between images you loaded perviously.
 * @author Julien Salvi
 *
 */
public class ImageViewerActivity extends FragmentActivity {
  
  //Pager references.
  public SectionsPagerAdapter sectionsPagerAdapter;
  public ViewPager pager;
  public RelativeLayout container;
  private List<Fragment> pagerFrags;

  //JSON references.
  private JSONParser parser;
  private JSONObject imagesData;
  
  //Variables references.
  private int start = 0;
  private int position = 0;
  private String query, imgExtra;
  
  //AsyncTask references.
  private LoadSwipeImagesTask swipeImgTask;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_image_viewer);
    
    //Override the transition animation.
    overridePendingTransition(R.anim.slide_right_in, android.R.anim.fade_out);
    
    //Setup UI.
    pager = (ViewPager) findViewById(R.id.pager_images);
    
    //Setup the fragments list and get extras if not null.
    pagerFrags = new ArrayList<Fragment>();
    if (getIntent().getExtras() != null) {
      position = getIntent().getExtras().getInt("position", 0);
      imgExtra = getIntent().getExtras().getString("images_data", null);
      query = getIntent().getExtras().getString("query", "");
    }
    
    if (imgExtra != null) {
      //Setup the JSON parser
      parser = new JSONParser();
      try {
        imagesData = new JSONObject(imgExtra);
        setupFragmentsList(imagesData.getJSONObject("responseData").getJSONArray("results"));
        //Setup the view pager
        sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        pager.setAdapter(sectionsPagerAdapter);
        pager.setOnPageChangeListener(new OnPageChangeListener() {
          @Override
          public void onPageSelected(int position) {
            if (position == (pagerFrags.size()-1)) {
              start += 8;
              loadList();
            }
          }
          
          @Override
          public void onPageScrollStateChanged(int state) { }

          @Override
          public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { }
          
        });
        //Move to the selected image.
        pager.setCurrentItem(position, false);
      } catch (Exception e) {
        //Launch a single fragment.
        Bundle arguments = new Bundle();
        try {
          arguments.putString("image_data", 
              imagesData.getJSONObject("responseData").getJSONArray("results").getJSONObject(position).toString());
          ImageViewerFragment fragment = new ImageViewerFragment();
          getSupportFragmentManager().beginTransaction()
              .add(R.id.image_container, fragment, "IMAGE_DETAILS").commit();
        } catch (JSONException ex) {
          Toast.makeText(this, "Fail to load the image", Toast.LENGTH_SHORT).show();
        }
        
      }
    } else {
      if (savedInstanceState == null) {
        // Create the detail fragment and add it to the activity
        // using a fragment transaction.
        Bundle arguments = new Bundle();
        try {
          arguments.putString("image_data", 
              imagesData.getJSONObject("responseData").getJSONArray("results").getJSONObject(position).toString());
          ImageViewerFragment fragment = new ImageViewerFragment();
          getSupportFragmentManager().beginTransaction()
              .add(R.id.image_container, fragment, "IMAGE_DETAILS").commit();
        } catch (Exception e) {
          Toast.makeText(this, "Fail to load the image", Toast.LENGTH_SHORT).show();
        }
        
      }
    }
  }
  
  /**
   * Load more images to swipe
   */
  protected void loadList() {
    if (swipeImgTask != null) {
      return;
    } else {
      if (parser == null) 
        parser = new JSONParser();
      //Init the new async task.
      swipeImgTask = new LoadSwipeImagesTask(true);
      swipeImgTask.execute(query);
    }
  }

  /**
   * Setup the list of fragment in order to build the view pager.
   * @param images
   * @throws JSONException 
   */
  private void setupFragmentsList(JSONArray images) throws JSONException {
    pagerFrags.clear();
    int len = images.length();
    for (int i = 0; i < len; i++) {
      //Init arguments and build the fragment
      Bundle arguments = new Bundle();
      arguments.putString("image_data", images.getJSONObject(i).toString());
      ImageViewerFragment fragment = new ImageViewerFragment();
      fragment.setArguments(arguments);
      //Add fragment to list if not null
      if (fragment != null)
        pagerFrags.add(fragment);
    }
  }

  /**
   * Pager adapter from swiping between images.
   * @author Julien Salvi
   *
   */
  private class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
      super(fm);
    }

    @Override
    public Fragment getItem(int position) {
      if (pagerFrags.get(position) != null) {
        return pagerFrags.get(position);
      } else {
        return null;
      }
    }
    
    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
      super.destroyItem(container, position, object);
    }

    @Override
    public int getCount() {  
      return pagerFrags.size();
    }
    
    @Override
    public CharSequence getPageTitle(int position) {
      return "imageFrag";
    }
  }
  
  /**
   * AsyncTask in order to laod more images in the view pager.
   * @author Julien Salvi
   *
   */
  private class LoadSwipeImagesTask extends AsyncTask<String, Void, Boolean> {
    
    //Local variables.
    private JSONObject imgLoadJson = null;
    private boolean load;
    
    public LoadSwipeImagesTask(boolean loadmore) {
      load = loadmore;
    }

    @Override
    protected Boolean doInBackground(String... params) {
      try {
        imgLoadJson = parser.fastGetRequest(Utils.SEARCH_IMG_URL+params[0]+"&start="+start);
        int len = imgLoadJson.getJSONObject("responseData").getJSONArray("results").length();
        for (int i=0; i < len; i++) {
          imagesData.getJSONObject("responseData").getJSONArray("results").put(
              imagesData.getJSONObject("responseData").getJSONArray("results").getJSONObject(i));
        }
        return true;
      } catch (Exception e) {
        return false;
      }
    }
    
    @Override
    protected void onPostExecute(Boolean success) {
      swipeImgTask = null;
        try {
          if (load && sectionsPagerAdapter != null) {
            //Load more images if pager not null.
            setupFragmentsList(imagesData.getJSONObject("responseData").getJSONArray("results"));
            sectionsPagerAdapter.notifyDataSetChanged();
          } else {
            //If not load, instantiate a new pager adapter with the new data.
            setupFragmentsList(imagesData.getJSONObject("responseData").getJSONArray("results"));
            sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
          pager.setAdapter(sectionsPagerAdapter);
          sectionsPagerAdapter.notifyDataSetChanged();
          }
      } catch (Exception e) {
        Toast.makeText(ImageViewerActivity.this, "Fail to load more images.", Toast.LENGTH_SHORT).show();
      }
    }

    @Override
    protected void onCancelled() {
      swipeImgTask = null;
    }
  }

}

Java Source Code List

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