Android Open Source - KnightNews_Android Feed Pager Activity

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License

The source code is released under:
Copyright (c) 2014, James Van Gaasbeck All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are m...
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Java Source Code

package knightnews.android;
/*from   www  . j  a v  a  2s. c o  m*/
import android.annotation.TargetApi;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.app.NavUtils;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.SoundEffectConstants;
import android.view.View;
import android.view.View.OnTouchListener;

import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;

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

public class FeedPagerActivity extends ActionBarActivity {
  private static final String TAG = "FeedPagerActivity";

  public static final String EXTRA_POSITION = "com.sigmobile.ucf_news.FeedPagerActivity" +
      ".EXTRA_POSITION";
  private static final String STATE_POSITION = "com.sigmobile.ucf_news.STATE_POSITION";

  private static final String PREFS_NAME = "KnightNewsPrefsFile";


  private static final String URL_JSON = "http://knightnews.com/api/get_recent_posts/";
  private static final String TAG_POSTS = "posts";
  private static final String TAG_URL = "url";
  private static final String TAG_TITLE_PLAIN = "title_plain";
  private static final String TAG_EXCERPT = "excerpt";
  private static final String TAG_CONTENT = "content";
  private static final String TAG_IMAGE = "image";
  private static final String TAG_AUTHOR = "author";
  private static final String TAG_NAME = "name";

  private static final float MIN_DISTANCE = 120;
  private float x1 = 0, x2 = 0;

  private ViewPager mPager;
  private Context mContext;

  @TargetApi(11)
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mContext = this;

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    fetchNewsItems();

    mPager = new ViewPager(this);
    mPager.setId(R.id.viewPager);

    if (savedInstanceState != null) {
      mPager.setCurrentItem(savedInstanceState.getInt(STATE_POSITION));
    }

    int item = getIntent().getIntExtra(EXTRA_POSITION, 0);

    mPager.setCurrentItem(item);

    mPager.setOnTouchListener(new OnTouchListener() {

      @Override
      public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
          case MotionEvent.ACTION_DOWN:
            x1 = event.getX();
            break;
          case MotionEvent.ACTION_UP:
            x2 = event.getX();
            float deltaX = x2 - x1;
            if (Math.abs(deltaX) > MIN_DISTANCE) {
              // Log.d(TAG, "*SWIPE*");
            } else {
              // Log.d(TAG, "*TAP*");
              v.playSoundEffect(SoundEffectConstants.CLICK);

              Intent i = new Intent(getApplicationContext(),
                  ReaderActivity.class);
              i.putExtra(ReaderFragment.KEY_STORY, StoryListManager
                  .getInstance(getApplicationContext())
                  .getStoryList().get(mPager.getCurrentItem()));
              i.putExtra(EXTRA_POSITION, mPager.getCurrentItem());

              startActivity(i);
            }
            break;
        }
        return false;
      }
    });

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
      mPager.setPageTransformer(true, new DepthPageTransformer());
    } else {
      mPager.setPageMargin(10);
    }

    setContentView(mPager);
    checkFirstTime();
  }

  @Override
  protected void onResume() {
    super.onResume();

  }

  @Override
  public void onDestroy() {
    RequestManager.getInstance(mContext).cancelRequestByTag(TAG);
    mContext = null;
    super.onDestroy();
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
      case android.R.id.home:

        Intent upIntent = NavUtils.getParentActivityIntent(this);
        upIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent
            .FLAG_ACTIVITY_SINGLE_TOP);
        NavUtils.navigateUpTo(this, upIntent);

        return true;
    }
    return super.onOptionsItemSelected(item);
  }

  @Override
  protected void onSaveInstanceState(Bundle outState) {
    outState.putInt(STATE_POSITION, mPager.getCurrentItem());
    super.onSaveInstanceState(outState);
  }

  private void setUpAdapter() {

    if (StoryListManager.getInstance(mContext).getStoryList() != null) {
      mPager.setAdapter(new PagerAdapter(getSupportFragmentManager()));
    } else {
      mPager.setAdapter(null);
    }
  }

  private void fetchNewsItems() {
    JsonObjectRequest mRequest = new JsonObjectRequest(URL_JSON, null,
        new Response.Listener<JSONObject>() {
          @Override
          public void onResponse(JSONObject response) {
//                            VolleyLog.v("Response:%n %s", response.toString(4));
//                            Log.i(TAG, "Response: " + response.toString());


            parseJSON(response);
            setUpAdapter();

          }
        }, new Response.ErrorListener() {
      @Override
      public void onErrorResponse(VolleyError error) {
        //VolleyLog.e("Error: ", error.getMessage());
      }
    }
    );
    RequestManager.getInstance(mContext).addToRequestQueue(mRequest, TAG);
  }

  private void checkFirstTime() {
    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);

    if (settings.getBoolean("my_first_time", true)) {

      FirstTimeDialog dia = FirstTimeDialog.newInstance();
      dia.show(getSupportFragmentManager(), "FirstTimeDialog");

      // record the fact that the app has been started at least once
      settings.edit().putBoolean("my_first_time", false).apply();
    }
  }

  private void parseJSON(JSONObject response) {
    if (response == null) {
      return;
    }

    try {
      JSONArray posts = response.getJSONArray(TAG_POSTS);

      //check if to make sure we don't add duplicate stories by comparing the titles
      //of the first stories.
      if (StoryListManager.getInstance(mContext).sizeOfStoryList() > 0) {
        StoryItem testStoryItem = new StoryItem();
        JSONObject testObj = posts.getJSONObject(0);
        testStoryItem.setTitle(testObj.getString(TAG_TITLE_PLAIN));
        String testTitle = testStoryItem.getTitle();

        if (testTitle.equals(StoryListManager.getInstance(mContext).getStoryItemAt(0)
                                             .getTitle())) {
          //return because the stories are the same
          return;
        } else {
          //If we have a new story just get rid of the old ones
          //so we don't create duplicates when adding the new story.
          StoryListManager.getInstance(mContext).removeAllStories();
        }
      }

      for (int i = 0; i < posts.length(); i++) {
        JSONObject p = posts.getJSONObject(i);

        JSONObject customFields = p.getJSONObject("custom_fields");
        String img = customFields.optString(TAG_IMAGE, HomeActivity.ERROR_IMAGE);


        String title = p.getString(TAG_TITLE_PLAIN);
        String url = p.getString(TAG_URL);
        String content = p.getString(TAG_CONTENT);
        String description = p.getString(TAG_EXCERPT);


        JSONObject author = p.getJSONObject(TAG_AUTHOR);
        String name = author.getString(TAG_NAME);

        StoryItem item = new StoryItem();
        item.setTitle(title);
        item.setContent(content);
        item.setDescription(description);
        item.setUrl(url);
        item.setPictureUrl(img);
        item.setAuthor(name);

        StoryListManager.getInstance(mContext).addStory(item);
      }

    } catch (JSONException e) {
      e.printStackTrace();
    }
  }

  private class PagerAdapter extends FragmentStatePagerAdapter {

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

    @Override
    public Fragment getItem(int pos) {
      StoryItem abridgedStory = StoryListManager
          .getInstance(getApplicationContext()).getStoryItemAt(pos);

      return AbridgedStoryFragment.newInstance(abridgedStory);
    }

    @Override
    public int getCount() {
      return StoryListManager.getInstance(mContext)
                             .sizeOfStoryList();
    }
  }

  private class DepthPageTransformer implements ViewPager.PageTransformer {
    private static final float MIN_SCALE = 0.75f;

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public void transformPage(View view, float position) {
      int pageWidth = view.getWidth();

      if (position < -1) { // [-Infinity,-1)
        // This page is way off-screen to the left.
        view.setAlpha(0);

      } else if (position <= 0) { // [-1,0]
        // Use the default slide transition when moving to the left page
        view.setAlpha(1);
        view.setTranslationX(0);
        view.setScaleX(1);
        view.setScaleY(1);

      } else if (position <= 1) { // (0,1]
        // Fade the page out.
        view.setAlpha(1 - position);

        // Counteract the default slide transition
        view.setTranslationX(pageWidth * -position);

        // Scale the page down (between MIN_SCALE and 1)
        float scaleFactor = MIN_SCALE + (1 - MIN_SCALE)
            * (1 - Math.abs(position));
        view.setScaleX(scaleFactor);
        view.setScaleY(scaleFactor);

      } else { // (1,+Infinity]
        // This page is way off-screen to the right.
        view.setAlpha(0);
      }
    }
  }

}
Java Source Code List
