src/com/android/mail/browse/ConversationPagerAdapter.java - platform/packages/apps/UnifiedEmail - Gitiles

 /*
  * Copyright (C) 2012 Google Inc.
  * Licensed to The Android Open Source Project.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.mail.browse;

 import android.app.Fragment;
 import android.app.FragmentManager;
 import android.content.res.Resources;
 import android.database.Cursor;
 import android.database.DataSetObserver;
 import android.os.Bundle;
 import android.os.Parcelable;
 import android.support.v4.view.ViewPager;
 import android.view.ViewGroup;

 import com.android.mail.R;
 import com.android.mail.providers.Account;
 import com.android.mail.providers.Conversation;
 import com.android.mail.providers.Folder;
 import com.android.mail.providers.UIProvider;
 import com.android.mail.ui.ConversationListCallbacks;
 import com.android.mail.ui.ConversationViewFragment;
 import com.android.mail.utils.FragmentStatePagerAdapter2;
 import com.android.mail.utils.LogUtils;
 import com.android.mail.utils.Utils;

 public class ConversationPagerAdapter extends FragmentStatePagerAdapter2 {

     private final DataSetObserver mListObserver = new ListObserver();
     private ConversationListCallbacks mListController;
     private final Bundle mCommonFragmentArgs;
     private final Conversation mInitialConversation;
     /**
      * In singleton mode, this adapter ignores the cursor contents and size, and acts as if the
      * data set size is exactly size=1, with {@link #mInitialConversation} at position 0.
      */
     private boolean mSingletonMode = true;
     /**
      * Adapter methods may trigger a data set change notification in the middle of a ViewPager
      * update, but they are not safe to handle, so we have to ignore them. This will not ignore
      * pager-external updates; it's impossible to be notified of an external change during
      * an update.
      *
      * TODO: Queue up changes like this, if there ever are any that actually modify the data set.
      * Right now there are none. Such a change would have to be of the form: instantiation or
      * setPrimary somehow adds or removes items from the conversation cursor. Crazy!
      */
     private boolean mSafeToNotify;
     /**
      * Need to keep this around to look up pager title strings.
      */
     private Resources mResources;
     /**
      * This isn't great to create a circular dependency, but our usage of {@link #getPageTitle(int)}
      * requires knowing which page is the currently visible to dynamically name offscreen pages
      * "newer" and "older". And {@link #setPrimaryItem(ViewGroup, int, Object)} does not work well
      * because it isn't updated as often as {@link ViewPager#getCurrentItem()} is.
      * <p>
      * We must be careful to null out this reference when the pager and adapter are decoupled to
      * minimize dangling references.
      */
     private ViewPager mPager;

     private static final String LOG_TAG = new LogUtils().getLogTag();

     public ConversationPagerAdapter(Resources res, FragmentManager fm, Account account,
             Folder folder, Conversation initialConversation) {
         super(fm, false /* enableSavedStates */);
         mResources = res;
         mCommonFragmentArgs = ConversationViewFragment.makeBasicArgs(account, folder);
         mInitialConversation = initialConversation;
     }

     public void setSingletonMode(boolean enabled) {
         if (mSingletonMode != enabled) {
             mSingletonMode = enabled;
             notifyDataSetChanged();
         }
     }

     public boolean isSingletonMode() {
         return mSingletonMode || getCursor() == null;
     }

     private Cursor getCursor() {
         if (mListController == null) {
             // Should never happen. It's the pager controller's responsibility to ensure the list
             // controller reference is around at least as long as the pager is active and has this
             // adapter.
             LogUtils.wtf(LOG_TAG, new Error(), "Pager adapter has an unexpected null cursor");
         }

         return mListController.getConversationListCursor();
     }

     @Override
     public Fragment getItem(int position) {
         final Conversation c;

         if (isSingletonMode()) {
             // cursor-less adapter is a size-1 cursor that points to mInitialConversation.
             // sanity-check
             if (position != 0) {
                 LogUtils.wtf(LOG_TAG, "pager cursor is null and position is non-zero: %d",
                         position);
             }
             c = mInitialConversation;
             c.position = 0;
         } else {
             final Cursor cursor = getCursor();
             if (!cursor.moveToPosition(position)) {
                 LogUtils.wtf(LOG_TAG, "unable to seek to ConversationCursor pos=%d (%s)", position,
                         cursor);
                 return null;
             }
             // TODO: switch to something like MessageCursor or AttachmentCursor
             // to re-use these models
             c = new Conversation(cursor);
             c.position = position;
         }
         final Fragment f = ConversationViewFragment.newInstance(mCommonFragmentArgs, c);
         LogUtils.d(LOG_TAG, "IN PagerAdapter.getItem, frag=%s subj=%s", f, c.subject);
         return f;
     }

     @Override
     public int getCount() {
         return (isSingletonMode()) ? 1 : getCursor().getCount();
     }

     @Override
     public int getItemPosition(Object item) {
         if (!(item instanceof ConversationViewFragment)) {
             LogUtils.wtf(LOG_TAG, "getItemPosition received unexpected item: %s", item);
         }

         final ConversationViewFragment fragment = (ConversationViewFragment) item;
         return getConversationPosition(fragment.getConversation());
     }

     @Override
     public void setPrimaryItem(ViewGroup container, int position, Object object) {
         LogUtils.d(LOG_TAG, "IN PagerAdapter.setPrimaryItem, pos=%d, frag=%s", position,
                 object);
         super.setPrimaryItem(container, position, object);
     }

     @Override
     public CharSequence getPageTitle(int position) {
         final String title;
         final int currentPosition = mPager.getCurrentItem();

         if (position == currentPosition) {
             title = mResources.getString(R.string.conversation_count, position + 1, getCount());
         } else {
             title = mResources.getString(position > currentPosition ?
                     R.string.conversation_newer : R.string.conversation_older);
         }
         return title;
     }

     @Override
     public Parcelable saveState() {
         LogUtils.d(LOG_TAG, "IN PagerAdapter.saveState");
         return super.saveState();
     }

     @Override
     public void restoreState(Parcelable state, ClassLoader loader) {
         LogUtils.d(LOG_TAG, "IN PagerAdapter.restoreState");
         super.restoreState(state, loader);
     }

     @Override
     public void startUpdate(ViewGroup container) {
         mSafeToNotify = false;
         super.startUpdate(container);
     }

     @Override
     public void finishUpdate(ViewGroup container) {
         super.finishUpdate(container);
         mSafeToNotify = true;
     }

     @Override
     public void notifyDataSetChanged() {
         if (!mSafeToNotify) {
             LogUtils.d(LOG_TAG, "IN PagerAdapter.notifyDataSetChanged, ignoring unsafe update");
             return;
         }
         super.notifyDataSetChanged();
     }

     @Override
     public void setItemVisible(Fragment item, boolean visible) {
         super.setItemVisible(item, visible);
         final ConversationViewFragment fragment = (ConversationViewFragment) item;
         fragment.setExtraUserVisibleHint(visible);

         if (visible && mListController != null) {
             final Conversation c = fragment.getConversation();
             LogUtils.d(LOG_TAG, "pager adapter setting current conv: %s (%s)", c.subject, item);
             mListController.setCurrentConversation(c);
         }
     }

     public int getConversationPosition(Conversation conv) {
         if (isSingletonMode()) {
             if (conv != mInitialConversation) {
                 LogUtils.wtf(LOG_TAG, "unable to find conversation with null pager cursor. c=%s",
                         conv);
                 return POSITION_NONE;
             }
             return 0;
         }

         final Cursor cursor = getCursor();

         final boolean networkWasEnabled = Utils.disableConversationCursorNetworkAccess(cursor);

         int result = POSITION_NONE;
         int pos = -1;
         while (cursor.moveToPosition(++pos)) {
             final long id = cursor.getLong(UIProvider.CONVERSATION_ID_COLUMN);
             if (conv.id == id) {
                 LogUtils.d(LOG_TAG, "pager adapter found repositioned convo '%s' at pos=%d",
                         conv.subject, pos);
                 result = pos;
                 break;
             }
         }

         if (networkWasEnabled) {
             Utils.enableConversationCursorNetworkAccess(cursor);
         }

         return result;
     }

     public void setPager(ViewPager pager) {
         mPager = pager;
     }

     public void setListController(ConversationListCallbacks listController) {
         if (mListController != null) {
             mListController.unregisterConversationListObserver(mListObserver);
         }
         mListController = listController;
         if (mListController != null) {
             mListController.registerConversationListObserver(mListObserver);

             notifyDataSetChanged();
         } else {
             // We're being torn down; do not notify.
             // Let the pager controller manage pager lifecycle.
         }
     }

     // update the pager dataset as the Controller's cursor changes
     private class ListObserver extends DataSetObserver {
         @Override
         public void onChanged() {
             notifyDataSetChanged();
         }
         @Override
         public void onInvalidated() {
         }
     }

 }
	/*
	* Copyright (C) 2012 Google Inc.
	* Licensed to The Android Open Source Project.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.mail.browse;

	import android.app.Fragment;
	import android.app.FragmentManager;
	import android.content.res.Resources;
	import android.database.Cursor;
	import android.database.DataSetObserver;
	import android.os.Bundle;
	import android.os.Parcelable;
	import android.support.v4.view.ViewPager;
	import android.view.ViewGroup;

	import com.android.mail.R;
	import com.android.mail.providers.Account;
	import com.android.mail.providers.Conversation;
	import com.android.mail.providers.Folder;
	import com.android.mail.providers.UIProvider;
	import com.android.mail.ui.ConversationListCallbacks;
	import com.android.mail.ui.ConversationViewFragment;
	import com.android.mail.utils.FragmentStatePagerAdapter2;
	import com.android.mail.utils.LogUtils;
	import com.android.mail.utils.Utils;

	public class ConversationPagerAdapter extends FragmentStatePagerAdapter2 {

	private final DataSetObserver mListObserver = new ListObserver();
	private ConversationListCallbacks mListController;
	private final Bundle mCommonFragmentArgs;
	private final Conversation mInitialConversation;
	/**
	* In singleton mode, this adapter ignores the cursor contents and size, and acts as if the
	* data set size is exactly size=1, with {@link #mInitialConversation} at position 0.
	*/
	private boolean mSingletonMode = true;
	/**
	* Adapter methods may trigger a data set change notification in the middle of a ViewPager
	* update, but they are not safe to handle, so we have to ignore them. This will not ignore
	* pager-external updates; it's impossible to be notified of an external change during
	* an update.
	*
	* TODO: Queue up changes like this, if there ever are any that actually modify the data set.
	* Right now there are none. Such a change would have to be of the form: instantiation or
	* setPrimary somehow adds or removes items from the conversation cursor. Crazy!
	*/
	private boolean mSafeToNotify;
	/**
	* Need to keep this around to look up pager title strings.
	*/
	private Resources mResources;
	/**
	* This isn't great to create a circular dependency, but our usage of {@link #getPageTitle(int)}
	* requires knowing which page is the currently visible to dynamically name offscreen pages
	* "newer" and "older". And {@link #setPrimaryItem(ViewGroup, int, Object)} does not work well
	* because it isn't updated as often as {@link ViewPager#getCurrentItem()} is.
	* <p>
	* We must be careful to null out this reference when the pager and adapter are decoupled to
	* minimize dangling references.
	*/
	private ViewPager mPager;

	private static final String LOG_TAG = new LogUtils().getLogTag();

	public ConversationPagerAdapter(Resources res, FragmentManager fm, Account account,
	Folder folder, Conversation initialConversation) {
	super(fm, false /* enableSavedStates */);
	mResources = res;
	mCommonFragmentArgs = ConversationViewFragment.makeBasicArgs(account, folder);
	mInitialConversation = initialConversation;
	}

	public void setSingletonMode(boolean enabled) {
	if (mSingletonMode != enabled) {
	mSingletonMode = enabled;
	notifyDataSetChanged();
	}
	}

	public boolean isSingletonMode() {
	return mSingletonMode \|\| getCursor() == null;
	}

	private Cursor getCursor() {
	if (mListController == null) {
	// Should never happen. It's the pager controller's responsibility to ensure the list
	// controller reference is around at least as long as the pager is active and has this
	// adapter.
	LogUtils.wtf(LOG_TAG, new Error(), "Pager adapter has an unexpected null cursor");
	}

	return mListController.getConversationListCursor();
	}

	@Override
	public Fragment getItem(int position) {
	final Conversation c;

	if (isSingletonMode()) {
	// cursor-less adapter is a size-1 cursor that points to mInitialConversation.
	// sanity-check
	if (position != 0) {
	LogUtils.wtf(LOG_TAG, "pager cursor is null and position is non-zero: %d",
	position);
	}
	c = mInitialConversation;
	c.position = 0;
	} else {
	final Cursor cursor = getCursor();
	if (!cursor.moveToPosition(position)) {
	LogUtils.wtf(LOG_TAG, "unable to seek to ConversationCursor pos=%d (%s)", position,
	cursor);
	return null;
	}
	// TODO: switch to something like MessageCursor or AttachmentCursor
	// to re-use these models
	c = new Conversation(cursor);
	c.position = position;
	}
	final Fragment f = ConversationViewFragment.newInstance(mCommonFragmentArgs, c);
	LogUtils.d(LOG_TAG, "IN PagerAdapter.getItem, frag=%s subj=%s", f, c.subject);
	return f;
	}

	@Override
	public int getCount() {
	return (isSingletonMode()) ? 1 : getCursor().getCount();
	}

	@Override
	public int getItemPosition(Object item) {
	if (!(item instanceof ConversationViewFragment)) {
	LogUtils.wtf(LOG_TAG, "getItemPosition received unexpected item: %s", item);
	}

	final ConversationViewFragment fragment = (ConversationViewFragment) item;
	return getConversationPosition(fragment.getConversation());
	}

	@Override
	public void setPrimaryItem(ViewGroup container, int position, Object object) {
	LogUtils.d(LOG_TAG, "IN PagerAdapter.setPrimaryItem, pos=%d, frag=%s", position,
	object);
	super.setPrimaryItem(container, position, object);
	}

	@Override
	public CharSequence getPageTitle(int position) {
	final String title;
	final int currentPosition = mPager.getCurrentItem();

	if (position == currentPosition) {
	title = mResources.getString(R.string.conversation_count, position + 1, getCount());
	} else {
	title = mResources.getString(position > currentPosition ?
	R.string.conversation_newer : R.string.conversation_older);
	}
	return title;
	}

	@Override
	public Parcelable saveState() {
	LogUtils.d(LOG_TAG, "IN PagerAdapter.saveState");
	return super.saveState();
	}

	@Override
	public void restoreState(Parcelable state, ClassLoader loader) {
	LogUtils.d(LOG_TAG, "IN PagerAdapter.restoreState");
	super.restoreState(state, loader);
	}

	@Override
	public void startUpdate(ViewGroup container) {
	mSafeToNotify = false;
	super.startUpdate(container);
	}

	@Override
	public void finishUpdate(ViewGroup container) {
	super.finishUpdate(container);
	mSafeToNotify = true;
	}

	@Override
	public void notifyDataSetChanged() {
	if (!mSafeToNotify) {
	LogUtils.d(LOG_TAG, "IN PagerAdapter.notifyDataSetChanged, ignoring unsafe update");
	return;
	}
	super.notifyDataSetChanged();
	}

	@Override
	public void setItemVisible(Fragment item, boolean visible) {
	super.setItemVisible(item, visible);
	final ConversationViewFragment fragment = (ConversationViewFragment) item;
	fragment.setExtraUserVisibleHint(visible);

	if (visible && mListController != null) {
	final Conversation c = fragment.getConversation();
	LogUtils.d(LOG_TAG, "pager adapter setting current conv: %s (%s)", c.subject, item);
	mListController.setCurrentConversation(c);
	}
	}

	public int getConversationPosition(Conversation conv) {
	if (isSingletonMode()) {
	if (conv != mInitialConversation) {
	LogUtils.wtf(LOG_TAG, "unable to find conversation with null pager cursor. c=%s",
	conv);
	return POSITION_NONE;
	}
	return 0;
	}

	final Cursor cursor = getCursor();

	final boolean networkWasEnabled = Utils.disableConversationCursorNetworkAccess(cursor);

	int result = POSITION_NONE;
	int pos = -1;
	while (cursor.moveToPosition(++pos)) {
	final long id = cursor.getLong(UIProvider.CONVERSATION_ID_COLUMN);
	if (conv.id == id) {
	LogUtils.d(LOG_TAG, "pager adapter found repositioned convo '%s' at pos=%d",
	conv.subject, pos);
	result = pos;
	break;
	}
	}

	if (networkWasEnabled) {
	Utils.enableConversationCursorNetworkAccess(cursor);
	}

	return result;
	}

	public void setPager(ViewPager pager) {
	mPager = pager;
	}

	public void setListController(ConversationListCallbacks listController) {
	if (mListController != null) {
	mListController.unregisterConversationListObserver(mListObserver);
	}
	mListController = listController;
	if (mListController != null) {
	mListController.registerConversationListObserver(mListObserver);

	notifyDataSetChanged();
	} else {
	// We're being torn down; do not notify.
	// Let the pager controller manage pager lifecycle.
	}
	}

	// update the pager dataset as the Controller's cursor changes
	private class ListObserver extends DataSetObserver {
	@Override
	public void onChanged() {
	notifyDataSetChanged();
	}
	@Override
	public void onInvalidated() {
	}
	}

	}