android/app/src/main/java/io/v/android/apps/reader/PdfViewerActivity.java - release.projects.reader - Git at Google

 // Copyright 2015 The Vanadium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package io.v.android.apps.reader;

 import android.content.Context;
 import android.content.Intent;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.provider.OpenableColumns;
 import android.support.v4.view.GestureDetectorCompat;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.View;
 import android.widget.ProgressBar;
 import android.widget.TextView;

 import com.google.android.gms.analytics.HitBuilders;

 import java.io.IOException;
 import java.io.InputStream;
 import java.util.HashMap;
 import java.util.Map;

 import io.v.android.apps.reader.db.DB;
 import io.v.android.apps.reader.db.DB.DBList;
 import io.v.android.apps.reader.model.IdFactory;
 import io.v.android.apps.reader.model.Listener;
 import io.v.android.apps.reader.vdl.DeviceMeta;
 import io.v.android.apps.reader.vdl.DeviceSet;
 import io.v.android.apps.reader.vdl.File;
 import io.v.v23.verror.VException;

 /**
  * Activity that shows the contents of the selected pdf file.
  */
 public class PdfViewerActivity extends BaseReaderActivity {

     private static final String TAG = PdfViewerActivity.class.getSimpleName();
     private static final int BLOCK_SIZE = 0x1000;   // 4K

     // Category string used for Google Analytics tracking.
     private static final String CATEGORY_PAGE_NAVIGATION = "Page Navigation";
     private static final String EXTRA_DEVICE_SET_ID = "device_set_id";

     private PdfViewWrapper mPdfView;
     private ProgressBar mProgressBar;
     private TextView mProgressText;
     private MenuItem mMenuItemLinkPage;

     private DBList<DeviceSet> mDeviceSets;
     private DeviceSet mCurrentDS;

     private CreateAndJoinDeviceSetTask mCreateAndJoinDeviceSetTask;

     /**
      * Helper methods for creating an intent to start a PdfViewerActivity.
      */
     public static Intent createIntent(Context context, String deviceSetId) {
         Intent intent = new Intent(context, PdfViewerActivity.class);
         intent.putExtra(EXTRA_DEVICE_SET_ID, deviceSetId);
         return intent;
     }

     public static Intent createIntent(Context context, Uri uri) {
         Intent intent = new Intent(context, PdfViewerActivity.class);
         intent.setData(uri);
         return intent;
     }

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

         setContentView(R.layout.activity_pdf_viewer);

         mPdfView = (PdfViewWrapper) findViewById(R.id.pdfview);
         mPdfView.init();

         mProgressBar = (ProgressBar) findViewById(R.id.pdf_progress_bar);
         mProgressText = (TextView) findViewById(R.id.pdf_progress_text);

         // Swipe gesture detection.
         final GestureDetectorCompat swipeDetector = SwipeGestureDetector.create(
                 this,
                 new SwipeGestureDetector.SimpleOnSwipeListener() {
                     @Override
                     public boolean onSwipeLeft() {
                         nextPage();
                         return true;
                     }

                     @Override
                     public boolean onSwipeRight() {
                         prevPage();
                         return true;
                     }
                 });

         mPdfView.setOnTouchListener(new View.OnTouchListener() {
             @Override
             public boolean onTouch(View v, MotionEvent event) {
                 return swipeDetector.onTouchEvent(event);
             }
         });
     }

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

         /**
          * Suppress the start process until the DB initialization is completed.
          * onStart() method will be called again after the user selects her blessings.
          */
         if (!getDB().isInitialized()) {
             return;
         }

         mDeviceSets = getDB().getDeviceSetList();
         mDeviceSets.setListener(new Listener() {
             @Override
             public void notifyItemChanged(int position) {
                 if (mCurrentDS == null) {
                     return;
                 }

                 DeviceSet changed = mDeviceSets.getItem(position);
                 if (!changed.getId().equals(mCurrentDS.getId())) {
                     return;
                 }

                 int oldPage = getPage();
                 mCurrentDS = cloneDeviceSet(changed);
                 int newPage = getPage();

                 DeviceMeta dm = getDeviceMeta();

                 if (oldPage != newPage) {
                     mPdfView.setPage(dm.getPage());
                     writeNavigationAction("Page Changed", newPage);
                 }

                 if (mMenuItemLinkPage != null) {
                     mMenuItemLinkPage.setChecked(dm.getLinked());
                 }
             }

             @Override
             public void notifyItemInserted(int position) {
                 // Nothing to do
             }

             @Override
             public void notifyItemRemoved(int position) {
                 // Nothing to do
             }
         });

         Intent intent = getIntent();

         if (intent.hasExtra(EXTRA_DEVICE_SET_ID)) {
             /**
              * Case #1.
              * The EXTRA_DEVICE_SET_ID value is set when this activity is started by touching one of
              * the existing device sets from the DeviceSetChooserActivity.
              */
             Log.i(TAG, "onStart: Case #1: started by selecting an existing device set.");

             // Get the device set from the DB and join it.
             DeviceSet ds = mDeviceSets.getItemById(intent.getStringExtra(EXTRA_DEVICE_SET_ID));
             joinDeviceSet(ds);
         } else if (intent.getData() != null) {
             /**
              * Case #2.
              * The intent.getData() is set as a content Uri when this activity is started by using
              * the floating action button from the DeviceSetChooserActivity and selecting one of the
              * local PDF files from the browser.
              */
             Log.i(TAG, "onStart: Case #2: started by using the floating action button.");

             Uri uri = intent.getData();
             createAndJoinDeviceSet(uri);
         } else if (intent.hasExtra(Intent.EXTRA_STREAM)) {
             /**
              * Case #3.
              * The EXTRA_STREAM value is set when this activity is started by receiving an implicit
              * intent from another app by sharing a PDF file to the reader app.
              */
             Log.i(TAG, "onStart: Case #3: started by an implicit intent from another app.");

             Uri uri = intent.getParcelableExtra(Intent.EXTRA_STREAM);
             createAndJoinDeviceSet(uri);
         }
     }

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

         if (mCreateAndJoinDeviceSetTask != null) {
             mCreateAndJoinDeviceSetTask.cancel(true);
         }
     }

     // TODO(youngseokyoon): generalize these clone methods
     private DeviceSet cloneDeviceSet(DeviceSet ds) {
         if (ds == null) {
             return null;
         }

         Map<String, DeviceMeta> devicesCopy = null;
         if (ds.getDevices() != null) {
             devicesCopy = new HashMap<>();
             for (Map.Entry<String, DeviceMeta> entry : ds.getDevices().entrySet()) {
                 devicesCopy.put(entry.getKey(), cloneDeviceMeta(entry.getValue()));
             }
         }

         return new DeviceSet(ds.getId(), ds.getFileId(), devicesCopy);
     }

     // TODO(youngseokyoon): generalize these clone methods
     private DeviceMeta cloneDeviceMeta(DeviceMeta dm) {
         if (dm == null) {
             return null;
         }

         return new DeviceMeta(dm.getDeviceId(), dm.getPage(), dm.getZoom(), dm.getLinked());
     }

     private void createAndJoinDeviceSet(final Uri fileUri) {
         mCreateAndJoinDeviceSetTask = new CreateAndJoinDeviceSetTask();
         mCreateAndJoinDeviceSetTask.execute(fileUri);
     }

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

         if (mDeviceSets != null) {
             mDeviceSets.discard();
         }

         leaveDeviceSet();
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.menu_pdf_viewer, menu);
         mMenuItemLinkPage = menu.findItem(R.id.action_link_page);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()) {
             case R.id.action_link_page:
                 toggleLinkedState(item.isChecked());
                 return true;

             default:
                 return super.onOptionsItemSelected(item);
         }
     }

     private void toggleLinkedState(boolean checked) {
         writeNavigationAction(checked ? "Unlink Page" : "Link Page");

         DeviceMeta dm = getDeviceMeta();
         if (dm == null) {
             return;
         }

         dm.setLinked(!checked);
         getDB().updateDeviceSet(mCurrentDS);
     }

     private DeviceMeta createDeviceMeta() {
         int page = 1;
         int zoom = 1;
         boolean linked = true;

         return new DeviceMeta(getDeviceId(), page, zoom, linked);
     }

     private DeviceSet createDeviceSet(File vFile) {
         String id = IdFactory.getRandomId();
         String fileId = vFile.getId();
         Map<String, DeviceMeta> devices = new HashMap<>();

         DeviceSet ds = new DeviceSet(id, fileId, devices);
         getDB().addDeviceSet(ds);

         return ds;
     }

     private void joinDeviceSet(DeviceSet ds) {
         mPdfView.loadPdfFile("/file_id/" + ds.getFileId());

         // Create a new device meta, and update the device set with it.
         Log.i(TAG, "Joining device set: " + ds.getId());
         DeviceMeta dm = createDeviceMeta();
         // TODO(youngseokyoon): don't wait till these operations are finished.
         ds.getDevices().put(dm.getDeviceId(), dm);
         getDB().updateDeviceSet(ds);

         mCurrentDS = ds;
     }

     private void leaveDeviceSet() {
         if (mCurrentDS == null) {
             return;
         }

         Log.i(TAG, "Leaving device set: " + mCurrentDS.getId());
         Map<String, DeviceMeta> devices = mCurrentDS.getDevices();
         devices.remove(getDeviceId());

         if (devices.isEmpty()) {
             Log.i(TAG, "Last one to leave the device set. Deleting " + mCurrentDS.getId());
             getDB().deleteDeviceSet(mCurrentDS.getId());
         } else {
             getDB().updateDeviceSet(mCurrentDS);
         }

         mCurrentDS = null;
     }

     private DeviceMeta getDeviceMeta() {
         return getDeviceMeta(mCurrentDS);
     }

     private DeviceMeta getDeviceMeta(DeviceSet ds) {
         if (ds == null) {
             return null;
         }

         return ds.getDevices().get(getDeviceId());
     }

     private int getPage() {
         DeviceMeta dm = getDeviceMeta();
         if (dm == null) {
             return 0;
         }

         return dm.getPage();
     }

     /**
      * Move all the linked pages to their previous pages.
      */
     private void prevPage() {
         writeNavigationAction("Previous Page");

         if (mCurrentDS == null || mPdfView.getPageCount() <= 0) {
             return;
         }

         DeviceSet ds = cloneDeviceSet(mCurrentDS);

         // First, check if this device is linked or not.
         // If not, simply move the page of the current device.
         if (!getDeviceMeta(ds).getLinked()) {
             DeviceMeta dm = getDeviceMeta(ds);
             if (dm.getPage() > 1) {
                 dm.setPage(dm.getPage() - 1);
             }

             getDB().updateDeviceSet(ds);
             return;
         }

         // Move all the linked pages
         Map<String, DeviceMeta> linkedDevices = getLinkedDevices(ds);
         int smallestPage = getSmallestPage(linkedDevices);

         if (smallestPage > 1) {
             for (String deviceId : linkedDevices.keySet()) {
                 DeviceMeta dm = linkedDevices.get(deviceId);
                 dm.setPage(dm.getPage() - 1);
             }

             getDB().updateDeviceSet(ds);
         }
     }

     /**
      * Move all the linked pages to their next pages.
      */
     private void nextPage() {
         writeNavigationAction("Next Page");

         if (mCurrentDS == null || mPdfView.getPageCount() <= 0) {
             return;
         }

         DeviceSet ds = cloneDeviceSet(mCurrentDS);

         // First, check if this device is linked or not.
         // If not, simply move the page of the current device.
         if (!getDeviceMeta(ds).getLinked()) {
             DeviceMeta dm = getDeviceMeta(ds);
             if (dm.getPage() < mPdfView.getPageCount()) {
                 dm.setPage(dm.getPage() + 1);
             }

             getDB().updateDeviceSet(ds);
             return;
         }

         // Move all the linked pages
         Map<String, DeviceMeta> linkedDevices = getLinkedDevices(ds);
         int largestPage = getLargestPage(linkedDevices);

         if (largestPage < mPdfView.getPageCount()) {
             for (String deviceId : linkedDevices.keySet()) {
                 DeviceMeta dm = linkedDevices.get(deviceId);
                 dm.setPage(dm.getPage() + 1);
             }

             getDB().updateDeviceSet(ds);
         }
     }

     private Map<String, DeviceMeta> getLinkedDevices(DeviceSet ds) {
         if (ds == null) {
             return null;
         }

         Map<String, DeviceMeta> devices = ds.getDevices();
         Map<String, DeviceMeta> result = new HashMap<>();
         for (String deviceId : devices.keySet()) {
             DeviceMeta dm = devices.get(deviceId);
             if (dm.getLinked()) {
                 result.put(deviceId, dm);
             }
         }

         return result;
     }

     private int getSmallestPage(Map<String, DeviceMeta> devices) {
         int result = -1;

         for (String deviceId : devices.keySet()) {
             DeviceMeta dm = devices.get(deviceId);
             if (result == -1 || dm.getPage() < result) {
                 result = dm.getPage();
             }
         }

         return result;
     }

     private int getLargestPage(Map<String, DeviceMeta> devices) {
         int result = -1;

         for (String deviceId : devices.keySet()) {
             DeviceMeta dm = devices.get(deviceId);
             if (result == -1 || dm.getPage() > result) {
                 result = dm.getPage();
             }
         }

         return result;
     }

     /**
      * Log a navigation event to the available trackers.
      */
     private void writeNavigationAction(String action) {
         writeNavigationAction(action, 0);
     }

     /**
      * Log a navigation event to the available trackers.
      */
     private void writeNavigationAction(String action, int value) {
         if (getTracker() != null) {
             getTracker().send(new HitBuilders.EventBuilder()
                     .setCustomDimension(1, Long.toString(System.currentTimeMillis()))
                     .setCustomDimension(2, Integer.toString(value))
                     .setCategory(CATEGORY_PAGE_NAVIGATION)
                     .setAction(action)
                     .setLabel(getDeviceId())
                     .build());
         }

         if (getLogger() != null) {
             getLogger().writeNavigationAction(action, value);
         }
     }

     private static void handleException(Throwable t) {
         Log.e(TAG, t.getMessage(), t);
     }

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         super.onActivityResult(requestCode, resultCode, data);

         Log.i(TAG, String.format("onActivityResult(%d, %d, data) called", requestCode, resultCode));

         // Any other activity results would be handled here.
         Log.w(TAG, String.format(
                 "Unhandled activity result. (requestCode: %d, resultCode: %d)",
                 requestCode, resultCode));
     }

     private void showProgressWidgets(final boolean showProgress) {
         if (showProgress) {
             mProgressText.setVisibility(View.VISIBLE);
             mProgressBar.setVisibility(View.VISIBLE);
             mPdfView.setVisibility(View.INVISIBLE);
         } else {
             mProgressText.setVisibility(View.INVISIBLE);
             mProgressBar.setVisibility(View.INVISIBLE);
             mPdfView.setVisibility(View.VISIBLE);
         }
     }

     private class CreateAndJoinDeviceSetTask extends AsyncTask<Uri, Integer, DeviceSet> {

         @Override
         protected void onPreExecute() {
             showProgressWidgets(true);
         }

         @Override
         protected DeviceSet doInBackground(Uri... uris) {
             Uri uri = null;
             try {
                 uri = uris[0];
                 Log.i(TAG, "CreateAndJoinDeviceSetTask$doInBackground: " + uri.toString());

                 byte[] bytes = getBytesFromUri(uri);
                 if (isCancelled()) {
                     return null;
                 }

                 File file = createFile(bytes, getTitleFromUri(uri));
                 if (isCancelled()) {
                     return null;
                 }

                 publishProgress(R.string.progress_creating_device_set, -1);
                 DeviceSet ds = createDeviceSet(file);

                 return ds;
             } catch (Exception e) {
                 Log.e(TAG, "Could not create the device set for uri: " + uri.toString() + ": "
                         + e.getMessage(), e);
                 return null;
             }
         }

         @Override
         protected void onProgressUpdate(Integer... values) {
             if (values.length == 2) {
                 mProgressText.setText(values[0]);

                 int maxProgress = values[1];
                 if (maxProgress >= 0) {
                     mProgressBar.setIndeterminate(false);
                     mProgressBar.setMax(maxProgress);
                     mProgressBar.setProgress(0);
                 } else {
                     mProgressBar.setIndeterminate(true);
                 }
             } else if (values.length == 1) {
                 mProgressBar.setProgress(values[0]);
             }
         }

         @Override
         protected void onPostExecute(DeviceSet ds) {
             PdfViewerActivity.this.mCreateAndJoinDeviceSetTask = null;

             // In case of an error, finish this activity and go back to the previous one.
             if (ds == null) {
                 finish();
                 return;
             }

             showProgressWidgets(false);
             joinDeviceSet(ds);
         }

         private byte[] getBytesFromUri(final Uri uri) throws IOException {
             Log.i(TAG, "getBytesFromUri: " + uri.toString());

             InputStream in = getContentResolver().openInputStream(uri);
             int total = in.available();
             int available = total;

             publishProgress(R.string.progress_reading_source_pdf, total);

             byte[] result = new byte[available];
             int cur = 0;
             int bytesRead;

             while ((bytesRead = in.read(result, cur, Math.min(BLOCK_SIZE, available))) != -1 &&
                     available > 0) {
                 cur += bytesRead;
                 available -= bytesRead;

                 publishProgress(cur);

                 if (isCancelled()) {
                     in.close();
                     return null;
                 }
             }

             in.close();

             return result;
         }

         private File createFile(final byte[] bytes, final String title) throws Exception {

             publishProgress(R.string.progress_writing_pdf, bytes.length);

             // Create a vdl File object representing this pdf file and put it in the db.
             DB.FileBuilder builder;
             builder = getDB().getFileBuilder(title);

             int cur = 0;
             int available = bytes.length;

             while (available > 0) {
                 int numBytes = Math.min(BLOCK_SIZE, available);
                 builder.write(bytes, cur, numBytes);
                 cur += numBytes;
                 available -= numBytes;

                 publishProgress(cur);

                 if (isCancelled()) {
                     builder.cancel();
                     return null;
                 }
             }

             publishProgress(R.string.progress_finishing_up_writing, -1);
             File vFile = builder.build();

             Log.i(TAG, "vFile created: " + vFile);
             if (vFile == null) {
                 throw new VException("Could not store the file content: " + title);
             }
             getDB().addFile(vFile);

             return vFile;
         }

         private String getTitleFromUri(Uri uri) {
             try {
                 Cursor cursor = getContentResolver().query(uri, null, null, null, null);

                 int nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
                 cursor.moveToFirst();
                 return cursor.getString(nameIndex);
             } catch (Exception e) {
                 handleException(e);

                 if (uri != null) {
                     return uri.getLastPathSegment();
                 }
             }

             return null;
         }
     }

 }
	// Copyright 2015 The Vanadium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package io.v.android.apps.reader;

	import android.content.Context;
	import android.content.Intent;
	import android.database.Cursor;
	import android.net.Uri;
	import android.os.AsyncTask;
	import android.os.Bundle;
	import android.provider.OpenableColumns;
	import android.support.v4.view.GestureDetectorCompat;
	import android.util.Log;
	import android.view.Menu;
	import android.view.MenuItem;
	import android.view.MotionEvent;
	import android.view.View;
	import android.widget.ProgressBar;
	import android.widget.TextView;

	import com.google.android.gms.analytics.HitBuilders;

	import java.io.IOException;
	import java.io.InputStream;
	import java.util.HashMap;
	import java.util.Map;

	import io.v.android.apps.reader.db.DB;
	import io.v.android.apps.reader.db.DB.DBList;
	import io.v.android.apps.reader.model.IdFactory;
	import io.v.android.apps.reader.model.Listener;
	import io.v.android.apps.reader.vdl.DeviceMeta;
	import io.v.android.apps.reader.vdl.DeviceSet;
	import io.v.android.apps.reader.vdl.File;
	import io.v.v23.verror.VException;

	/**
	* Activity that shows the contents of the selected pdf file.
	*/
	public class PdfViewerActivity extends BaseReaderActivity {

	private static final String TAG = PdfViewerActivity.class.getSimpleName();
	private static final int BLOCK_SIZE = 0x1000; // 4K

	// Category string used for Google Analytics tracking.
	private static final String CATEGORY_PAGE_NAVIGATION = "Page Navigation";
	private static final String EXTRA_DEVICE_SET_ID = "device_set_id";

	private PdfViewWrapper mPdfView;
	private ProgressBar mProgressBar;
	private TextView mProgressText;
	private MenuItem mMenuItemLinkPage;

	private DBList<DeviceSet> mDeviceSets;
	private DeviceSet mCurrentDS;

	private CreateAndJoinDeviceSetTask mCreateAndJoinDeviceSetTask;

	/**
	* Helper methods for creating an intent to start a PdfViewerActivity.
	*/
	public static Intent createIntent(Context context, String deviceSetId) {
	Intent intent = new Intent(context, PdfViewerActivity.class);
	intent.putExtra(EXTRA_DEVICE_SET_ID, deviceSetId);
	return intent;
	}

	public static Intent createIntent(Context context, Uri uri) {
	Intent intent = new Intent(context, PdfViewerActivity.class);
	intent.setData(uri);
	return intent;
	}

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

	setContentView(R.layout.activity_pdf_viewer);

	mPdfView = (PdfViewWrapper) findViewById(R.id.pdfview);
	mPdfView.init();

	mProgressBar = (ProgressBar) findViewById(R.id.pdf_progress_bar);
	mProgressText = (TextView) findViewById(R.id.pdf_progress_text);

	// Swipe gesture detection.
	final GestureDetectorCompat swipeDetector = SwipeGestureDetector.create(
	this,
	new SwipeGestureDetector.SimpleOnSwipeListener() {
	@Override
	public boolean onSwipeLeft() {
	nextPage();
	return true;
	}

	@Override
	public boolean onSwipeRight() {
	prevPage();
	return true;
	}
	});

	mPdfView.setOnTouchListener(new View.OnTouchListener() {
	@Override
	public boolean onTouch(View v, MotionEvent event) {
	return swipeDetector.onTouchEvent(event);
	}
	});
	}

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

	/**
	* Suppress the start process until the DB initialization is completed.
	* onStart() method will be called again after the user selects her blessings.
	*/
	if (!getDB().isInitialized()) {
	return;
	}

	mDeviceSets = getDB().getDeviceSetList();
	mDeviceSets.setListener(new Listener() {
	@Override
	public void notifyItemChanged(int position) {
	if (mCurrentDS == null) {
	return;
	}

	DeviceSet changed = mDeviceSets.getItem(position);
	if (!changed.getId().equals(mCurrentDS.getId())) {
	return;
	}

	int oldPage = getPage();
	mCurrentDS = cloneDeviceSet(changed);
	int newPage = getPage();

	DeviceMeta dm = getDeviceMeta();

	if (oldPage != newPage) {
	mPdfView.setPage(dm.getPage());
	writeNavigationAction("Page Changed", newPage);
	}

	if (mMenuItemLinkPage != null) {
	mMenuItemLinkPage.setChecked(dm.getLinked());
	}
	}

	@Override
	public void notifyItemInserted(int position) {
	// Nothing to do
	}

	@Override
	public void notifyItemRemoved(int position) {
	// Nothing to do
	}
	});

	Intent intent = getIntent();

	if (intent.hasExtra(EXTRA_DEVICE_SET_ID)) {
	/**
	* Case #1.
	* The EXTRA_DEVICE_SET_ID value is set when this activity is started by touching one of
	* the existing device sets from the DeviceSetChooserActivity.
	*/
	Log.i(TAG, "onStart: Case #1: started by selecting an existing device set.");

	// Get the device set from the DB and join it.
	DeviceSet ds = mDeviceSets.getItemById(intent.getStringExtra(EXTRA_DEVICE_SET_ID));
	joinDeviceSet(ds);
	} else if (intent.getData() != null) {
	/**
	* Case #2.
	* The intent.getData() is set as a content Uri when this activity is started by using
	* the floating action button from the DeviceSetChooserActivity and selecting one of the
	* local PDF files from the browser.
	*/
	Log.i(TAG, "onStart: Case #2: started by using the floating action button.");

	Uri uri = intent.getData();
	createAndJoinDeviceSet(uri);
	} else if (intent.hasExtra(Intent.EXTRA_STREAM)) {
	/**
	* Case #3.
	* The EXTRA_STREAM value is set when this activity is started by receiving an implicit
	* intent from another app by sharing a PDF file to the reader app.
	*/
	Log.i(TAG, "onStart: Case #3: started by an implicit intent from another app.");

	Uri uri = intent.getParcelableExtra(Intent.EXTRA_STREAM);
	createAndJoinDeviceSet(uri);
	}
	}

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

	if (mCreateAndJoinDeviceSetTask != null) {
	mCreateAndJoinDeviceSetTask.cancel(true);
	}
	}

	// TODO(youngseokyoon): generalize these clone methods
	private DeviceSet cloneDeviceSet(DeviceSet ds) {
	if (ds == null) {
	return null;
	}

	Map<String, DeviceMeta> devicesCopy = null;
	if (ds.getDevices() != null) {
	devicesCopy = new HashMap<>();
	for (Map.Entry<String, DeviceMeta> entry : ds.getDevices().entrySet()) {
	devicesCopy.put(entry.getKey(), cloneDeviceMeta(entry.getValue()));
	}
	}

	return new DeviceSet(ds.getId(), ds.getFileId(), devicesCopy);
	}

	// TODO(youngseokyoon): generalize these clone methods
	private DeviceMeta cloneDeviceMeta(DeviceMeta dm) {
	if (dm == null) {
	return null;
	}

	return new DeviceMeta(dm.getDeviceId(), dm.getPage(), dm.getZoom(), dm.getLinked());
	}

	private void createAndJoinDeviceSet(final Uri fileUri) {
	mCreateAndJoinDeviceSetTask = new CreateAndJoinDeviceSetTask();
	mCreateAndJoinDeviceSetTask.execute(fileUri);
	}

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

	if (mDeviceSets != null) {
	mDeviceSets.discard();
	}

	leaveDeviceSet();
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
	// Inflate the menu; this adds items to the action bar if it is present.
	getMenuInflater().inflate(R.menu.menu_pdf_viewer, menu);
	mMenuItemLinkPage = menu.findItem(R.id.action_link_page);
	return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
	switch (item.getItemId()) {
	case R.id.action_link_page:
	toggleLinkedState(item.isChecked());
	return true;

	default:
	return super.onOptionsItemSelected(item);
	}
	}

	private void toggleLinkedState(boolean checked) {
	writeNavigationAction(checked ? "Unlink Page" : "Link Page");

	DeviceMeta dm = getDeviceMeta();
	if (dm == null) {
	return;
	}

	dm.setLinked(!checked);
	getDB().updateDeviceSet(mCurrentDS);
	}

	private DeviceMeta createDeviceMeta() {
	int page = 1;
	int zoom = 1;
	boolean linked = true;

	return new DeviceMeta(getDeviceId(), page, zoom, linked);
	}

	private DeviceSet createDeviceSet(File vFile) {
	String id = IdFactory.getRandomId();
	String fileId = vFile.getId();
	Map<String, DeviceMeta> devices = new HashMap<>();

	DeviceSet ds = new DeviceSet(id, fileId, devices);
	getDB().addDeviceSet(ds);

	return ds;
	}

	private void joinDeviceSet(DeviceSet ds) {
	mPdfView.loadPdfFile("/file_id/" + ds.getFileId());

	// Create a new device meta, and update the device set with it.
	Log.i(TAG, "Joining device set: " + ds.getId());
	DeviceMeta dm = createDeviceMeta();
	// TODO(youngseokyoon): don't wait till these operations are finished.
	ds.getDevices().put(dm.getDeviceId(), dm);
	getDB().updateDeviceSet(ds);

	mCurrentDS = ds;
	}

	private void leaveDeviceSet() {
	if (mCurrentDS == null) {
	return;
	}

	Log.i(TAG, "Leaving device set: " + mCurrentDS.getId());
	Map<String, DeviceMeta> devices = mCurrentDS.getDevices();
	devices.remove(getDeviceId());

	if (devices.isEmpty()) {
	Log.i(TAG, "Last one to leave the device set. Deleting " + mCurrentDS.getId());
	getDB().deleteDeviceSet(mCurrentDS.getId());
	} else {
	getDB().updateDeviceSet(mCurrentDS);
	}

	mCurrentDS = null;
	}

	private DeviceMeta getDeviceMeta() {
	return getDeviceMeta(mCurrentDS);
	}

	private DeviceMeta getDeviceMeta(DeviceSet ds) {
	if (ds == null) {
	return null;
	}

	return ds.getDevices().get(getDeviceId());
	}

	private int getPage() {
	DeviceMeta dm = getDeviceMeta();
	if (dm == null) {
	return 0;
	}

	return dm.getPage();
	}

	/**
	* Move all the linked pages to their previous pages.
	*/
	private void prevPage() {
	writeNavigationAction("Previous Page");

	if (mCurrentDS == null \|\| mPdfView.getPageCount() <= 0) {
	return;
	}

	DeviceSet ds = cloneDeviceSet(mCurrentDS);

	// First, check if this device is linked or not.
	// If not, simply move the page of the current device.
	if (!getDeviceMeta(ds).getLinked()) {
	DeviceMeta dm = getDeviceMeta(ds);
	if (dm.getPage() > 1) {
	dm.setPage(dm.getPage() - 1);
	}

	getDB().updateDeviceSet(ds);
	return;
	}

	// Move all the linked pages
	Map<String, DeviceMeta> linkedDevices = getLinkedDevices(ds);
	int smallestPage = getSmallestPage(linkedDevices);

	if (smallestPage > 1) {
	for (String deviceId : linkedDevices.keySet()) {
	DeviceMeta dm = linkedDevices.get(deviceId);
	dm.setPage(dm.getPage() - 1);
	}

	getDB().updateDeviceSet(ds);
	}
	}

	/**
	* Move all the linked pages to their next pages.
	*/
	private void nextPage() {
	writeNavigationAction("Next Page");

	if (mCurrentDS == null \|\| mPdfView.getPageCount() <= 0) {
	return;
	}

	DeviceSet ds = cloneDeviceSet(mCurrentDS);

	// First, check if this device is linked or not.
	// If not, simply move the page of the current device.
	if (!getDeviceMeta(ds).getLinked()) {
	DeviceMeta dm = getDeviceMeta(ds);
	if (dm.getPage() < mPdfView.getPageCount()) {
	dm.setPage(dm.getPage() + 1);
	}

	getDB().updateDeviceSet(ds);
	return;
	}

	// Move all the linked pages
	Map<String, DeviceMeta> linkedDevices = getLinkedDevices(ds);
	int largestPage = getLargestPage(linkedDevices);

	if (largestPage < mPdfView.getPageCount()) {
	for (String deviceId : linkedDevices.keySet()) {
	DeviceMeta dm = linkedDevices.get(deviceId);
	dm.setPage(dm.getPage() + 1);
	}

	getDB().updateDeviceSet(ds);
	}
	}

	private Map<String, DeviceMeta> getLinkedDevices(DeviceSet ds) {
	if (ds == null) {
	return null;
	}

	Map<String, DeviceMeta> devices = ds.getDevices();
	Map<String, DeviceMeta> result = new HashMap<>();
	for (String deviceId : devices.keySet()) {
	DeviceMeta dm = devices.get(deviceId);
	if (dm.getLinked()) {
	result.put(deviceId, dm);
	}
	}

	return result;
	}

	private int getSmallestPage(Map<String, DeviceMeta> devices) {
	int result = -1;

	for (String deviceId : devices.keySet()) {
	DeviceMeta dm = devices.get(deviceId);
	if (result == -1 \|\| dm.getPage() < result) {
	result = dm.getPage();
	}
	}

	return result;
	}

	private int getLargestPage(Map<String, DeviceMeta> devices) {
	int result = -1;

	for (String deviceId : devices.keySet()) {
	DeviceMeta dm = devices.get(deviceId);
	if (result == -1 \|\| dm.getPage() > result) {
	result = dm.getPage();
	}
	}

	return result;
	}

	/**
	* Log a navigation event to the available trackers.
	*/
	private void writeNavigationAction(String action) {
	writeNavigationAction(action, 0);
	}

	/**
	* Log a navigation event to the available trackers.
	*/
	private void writeNavigationAction(String action, int value) {
	if (getTracker() != null) {
	getTracker().send(new HitBuilders.EventBuilder()
	.setCustomDimension(1, Long.toString(System.currentTimeMillis()))
	.setCustomDimension(2, Integer.toString(value))
	.setCategory(CATEGORY_PAGE_NAVIGATION)
	.setAction(action)
	.setLabel(getDeviceId())
	.build());
	}

	if (getLogger() != null) {
	getLogger().writeNavigationAction(action, value);
	}
	}

	private static void handleException(Throwable t) {
	Log.e(TAG, t.getMessage(), t);
	}

	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
	super.onActivityResult(requestCode, resultCode, data);

	Log.i(TAG, String.format("onActivityResult(%d, %d, data) called", requestCode, resultCode));

	// Any other activity results would be handled here.
	Log.w(TAG, String.format(
	"Unhandled activity result. (requestCode: %d, resultCode: %d)",
	requestCode, resultCode));
	}

	private void showProgressWidgets(final boolean showProgress) {
	if (showProgress) {
	mProgressText.setVisibility(View.VISIBLE);
	mProgressBar.setVisibility(View.VISIBLE);
	mPdfView.setVisibility(View.INVISIBLE);
	} else {
	mProgressText.setVisibility(View.INVISIBLE);
	mProgressBar.setVisibility(View.INVISIBLE);
	mPdfView.setVisibility(View.VISIBLE);
	}
	}

	private class CreateAndJoinDeviceSetTask extends AsyncTask<Uri, Integer, DeviceSet> {

	@Override
	protected void onPreExecute() {
	showProgressWidgets(true);
	}

	@Override
	protected DeviceSet doInBackground(Uri... uris) {
	Uri uri = null;
	try {
	uri = uris[0];
	Log.i(TAG, "CreateAndJoinDeviceSetTask$doInBackground: " + uri.toString());

	byte[] bytes = getBytesFromUri(uri);
	if (isCancelled()) {
	return null;
	}

	File file = createFile(bytes, getTitleFromUri(uri));
	if (isCancelled()) {
	return null;
	}

	publishProgress(R.string.progress_creating_device_set, -1);
	DeviceSet ds = createDeviceSet(file);

	return ds;
	} catch (Exception e) {
	Log.e(TAG, "Could not create the device set for uri: " + uri.toString() + ": "
	+ e.getMessage(), e);
	return null;
	}
	}

	@Override
	protected void onProgressUpdate(Integer... values) {
	if (values.length == 2) {
	mProgressText.setText(values[0]);

	int maxProgress = values[1];
	if (maxProgress >= 0) {
	mProgressBar.setIndeterminate(false);
	mProgressBar.setMax(maxProgress);
	mProgressBar.setProgress(0);
	} else {
	mProgressBar.setIndeterminate(true);
	}
	} else if (values.length == 1) {
	mProgressBar.setProgress(values[0]);
	}
	}

	@Override
	protected void onPostExecute(DeviceSet ds) {
	PdfViewerActivity.this.mCreateAndJoinDeviceSetTask = null;

	// In case of an error, finish this activity and go back to the previous one.
	if (ds == null) {
	finish();
	return;
	}

	showProgressWidgets(false);
	joinDeviceSet(ds);
	}

	private byte[] getBytesFromUri(final Uri uri) throws IOException {
	Log.i(TAG, "getBytesFromUri: " + uri.toString());

	InputStream in = getContentResolver().openInputStream(uri);
	int total = in.available();
	int available = total;

	publishProgress(R.string.progress_reading_source_pdf, total);

	byte[] result = new byte[available];
	int cur = 0;
	int bytesRead;

	while ((bytesRead = in.read(result, cur, Math.min(BLOCK_SIZE, available))) != -1 &&
	available > 0) {
	cur += bytesRead;
	available -= bytesRead;

	publishProgress(cur);

	if (isCancelled()) {
	in.close();
	return null;
	}
	}

	in.close();

	return result;
	}

	private File createFile(final byte[] bytes, final String title) throws Exception {

	publishProgress(R.string.progress_writing_pdf, bytes.length);

	// Create a vdl File object representing this pdf file and put it in the db.
	DB.FileBuilder builder;
	builder = getDB().getFileBuilder(title);

	int cur = 0;
	int available = bytes.length;

	while (available > 0) {
	int numBytes = Math.min(BLOCK_SIZE, available);
	builder.write(bytes, cur, numBytes);
	cur += numBytes;
	available -= numBytes;

	publishProgress(cur);

	if (isCancelled()) {
	builder.cancel();
	return null;
	}
	}

	publishProgress(R.string.progress_finishing_up_writing, -1);
	File vFile = builder.build();

	Log.i(TAG, "vFile created: " + vFile);
	if (vFile == null) {
	throw new VException("Could not store the file content: " + title);
	}
	getDB().addFile(vFile);

	return vFile;
	}

	private String getTitleFromUri(Uri uri) {
	try {
	Cursor cursor = getContentResolver().query(uri, null, null, null, null);

	int nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
	cursor.moveToFirst();
	return cursor.getString(nameIndex);
	} catch (Exception e) {
	handleException(e);

	if (uri != null) {
	return uri.getLastPathSegment();
	}
	}

	return null;
	}
	}

	}