common/src/java/com/example/android/common/actionbarcompat/MultiSelectionUtil.java - platform/developers/samples/android - Git at Google

 /*
  * Copyright (C) 2013 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.example.android.common.actionbarcompat;

 import android.os.Bundle;
 import android.support.v7.app.ActionBarActivity;
 import android.support.v7.view.ActionMode;
 import android.util.Pair;
 import android.util.SparseBooleanArray;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.AbsListView;
 import android.widget.Adapter;
 import android.widget.AdapterView;
 import android.widget.ListView;

 import java.util.HashSet;

 /**
  * Utilities for handling multiple selection in list views. Contains functionality similar to {@link
  * AbsListView#CHOICE_MODE_MULTIPLE_MODAL} which works with {@link ActionBarActivity} and
  * backward-compatible action bars.
  */
 public class MultiSelectionUtil {

     /**
      * Attach a Controller to the given <code>listView</code>, <code>activity</code>
      * and <code>listener</code>.
      *
      * @param listView ListView which displays {@link android.widget.Checkable} items.
      * @param activity Activity which contains the ListView.
      * @param listener Listener that will manage the selection mode.
      * @return the attached Controller instance.
      */
     public static Controller attachMultiSelectionController(final ListView listView,
             final ActionBarActivity activity, final MultiChoiceModeListener listener) {
         return new Controller(listView, activity, listener);
     }

     /**
      * Class which provides functionality similar to {@link AbsListView#CHOICE_MODE_MULTIPLE_MODAL}
      * for the {@link ListView} provided to it. A
      * {@link android.widget.AdapterView.OnItemLongClickListener} is set on the ListView so that
      * when an item is long-clicked an ActionBarCompat Action Mode is started. Once started, a
      * {@link android.widget.AdapterView.OnItemClickListener} is set so that an item click toggles
      * that item's checked state.
      */
     public static class Controller {

         private final ListView mListView;
         private final ActionBarActivity mActivity;
         private final MultiChoiceModeListener mListener;
         private final Callbacks mCallbacks;

         // Current Action Mode (if there is one)
         private ActionMode mActionMode;

         // Keeps record of any items that should be checked on the next action mode creation
         private HashSet<Pair<Integer, Long>> mItemsToCheck;

         // Reference to the replace OnItemClickListener (so it can be restored later)
         private AdapterView.OnItemClickListener mOldItemClickListener;

         private final Runnable mSetChoiceModeNoneRunnable = new Runnable() {
             @Override
             public void run() {
                 mListView.setChoiceMode(AbsListView.CHOICE_MODE_NONE);
             }
         };

         private Controller(ListView listView, ActionBarActivity activity,
                 MultiChoiceModeListener listener) {
             mListView = listView;
             mActivity = activity;
             mListener = listener;
             mCallbacks = new Callbacks();

             // We set ourselves as the OnItemLongClickListener so we know when to start
             // an Action Mode
             listView.setOnItemLongClickListener(mCallbacks);
         }

         /**
          * Finish the current Action Mode (if there is one).
          */
         public void finish() {
             if (mActionMode != null) {
                 mActionMode.finish();
             }
         }

         /**
          * This method should be called from your {@link ActionBarActivity} or
          * {@link android.support.v4.app.Fragment Fragment} to allow the controller to restore any
          * instance state.
          *
          * @param savedInstanceState - The state passed to your Activity or Fragment.
          */
         public void restoreInstanceState(Bundle savedInstanceState) {
             if (savedInstanceState != null) {
                 long[] checkedIds = savedInstanceState.getLongArray(getStateKey());
                 if (checkedIds != null && checkedIds.length > 0) {
                     HashSet<Long> idsToCheckOnRestore = new HashSet<Long>();
                     for (long id : checkedIds) {
                         idsToCheckOnRestore.add(id);
                     }
                     tryRestoreInstanceState(idsToCheckOnRestore);
                 }
             }
         }

         /**
          * This method should be called from
          * {@link ActionBarActivity#onSaveInstanceState(android.os.Bundle)} or
          * {@link android.support.v4.app.Fragment#onSaveInstanceState(android.os.Bundle)
          * Fragment.onSaveInstanceState(Bundle)} to allow the controller to save its instance
          * state.
          *
          * @param outState - The state passed to your Activity or Fragment.
          */
         public void saveInstanceState(Bundle outState) {
             if (mActionMode != null && mListView.getAdapter().hasStableIds()) {
                 outState.putLongArray(getStateKey(), mListView.getCheckedItemIds());
             }
         }

         // Internal utility methods

         private String getStateKey() {
             return MultiSelectionUtil.class.getSimpleName() + "_" + mListView.getId();
         }

         private void tryRestoreInstanceState(HashSet<Long> idsToCheckOnRestore) {
             if (idsToCheckOnRestore == null || mListView.getAdapter() == null) {
                 return;
             }

             boolean idsFound = false;
             Adapter adapter = mListView.getAdapter();
             for (int pos = adapter.getCount() - 1; pos >= 0; pos--) {
                 if (idsToCheckOnRestore.contains(adapter.getItemId(pos))) {
                     idsFound = true;
                     if (mItemsToCheck == null) {
                         mItemsToCheck = new HashSet<Pair<Integer, Long>>();
                     }
                     mItemsToCheck.add(new Pair<Integer, Long>(pos, adapter.getItemId(pos)));
                 }
             }

             if (idsFound) {
                 // We found some IDs that were checked. Let's now restore the multi-selection
                 // state.
                 mActionMode = mActivity.startSupportActionMode(mCallbacks);
             }
         }

         /**
          * This class encapsulates all of the callbacks necessary for the controller class.
          */
         final class Callbacks implements ActionMode.Callback, AdapterView.OnItemClickListener,
                 AdapterView.OnItemLongClickListener {

             @Override
             public final boolean onCreateActionMode(ActionMode actionMode, Menu menu) {
                 if (mListener.onCreateActionMode(actionMode, menu)) {
                     mActionMode = actionMode;
                     // Keep a reference to the existing OnItemClickListener so we can restore it
                     mOldItemClickListener = mListView.getOnItemClickListener();

                     // Set-up the ListView to emulate CHOICE_MODE_MULTIPLE_MODAL
                     mListView.setOnItemClickListener(this);
                     mListView.setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE);
                     mListView.removeCallbacks(mSetChoiceModeNoneRunnable);

                     // If there are some items to check, do it now
                     if (mItemsToCheck != null) {
                         for (Pair<Integer, Long> posAndId : mItemsToCheck) {
                             mListView.setItemChecked(posAndId.first, true);
                             // Notify the listener that the item has been checked
                             mListener.onItemCheckedStateChanged(mActionMode, posAndId.first,
                                     posAndId.second, true);
                         }
                     }
                     return true;
                 }
                 return false;
             }

             @Override
             public boolean onPrepareActionMode(ActionMode actionMode, Menu menu) {
                 // Proxy listener
                 return mListener.onPrepareActionMode(actionMode, menu);
             }

             @Override
             public boolean onActionItemClicked(ActionMode actionMode, MenuItem menuItem) {
                 // Proxy listener
                 return mListener.onActionItemClicked(actionMode, menuItem);
             }

             @Override
             public void onDestroyActionMode(ActionMode actionMode) {
                 mListener.onDestroyActionMode(actionMode);

                 // Clear all the checked items
                 SparseBooleanArray checkedPositions = mListView.getCheckedItemPositions();
                 if (checkedPositions != null) {
                     for (int i = 0; i < checkedPositions.size(); i++) {
                         mListView.setItemChecked(checkedPositions.keyAt(i), false);
                     }
                 }

                 // Restore the original onItemClickListener
                 mListView.setOnItemClickListener(mOldItemClickListener);

                 // Clear the Action Mode
                 mActionMode = null;

                 // Reset the ListView's Choice Mode
                 mListView.post(mSetChoiceModeNoneRunnable);
             }

             @Override
             public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                 // Check to see what the new checked state is, and then notify the listener
                 final boolean checked = mListView.isItemChecked(position);
                 mListener.onItemCheckedStateChanged(mActionMode, position, id, checked);

                 boolean hasCheckedItem = checked;

                 // Check to see if we have any checked items
                 if (!hasCheckedItem) {
                     SparseBooleanArray checkedItemPositions = mListView.getCheckedItemPositions();
                     if (checkedItemPositions != null) {
                         // Iterate through the SparseBooleanArray to see if there is a checked item
                         int i = 0;
                         while (!hasCheckedItem && i < checkedItemPositions.size()) {
                             hasCheckedItem = checkedItemPositions.valueAt(i++);
                         }
                     }
                 }

                 // If we don't have any checked items, finish the action mode
                 if (!hasCheckedItem) {
                     mActionMode.finish();
                 }
             }

             @Override
             public boolean onItemLongClick(AdapterView<?> adapterView, View view, int position,
                     long id) {
                 // If we already have an action mode started return false
                 // (onItemClick will be called anyway)
                 if (mActionMode != null) {
                     return false;
                 }

                 mItemsToCheck = new HashSet<Pair<Integer, Long>>();
                 mItemsToCheck.add(new Pair<Integer, Long>(position, id));
                 mActionMode = mActivity.startSupportActionMode(this);
                 return true;
             }
         }
     }

     /**
      * @see android.widget.AbsListView.MultiChoiceModeListener
      */
     public static interface MultiChoiceModeListener extends ActionMode.Callback {

         /**
          * @see android.widget.AbsListView.MultiChoiceModeListener#onItemCheckedStateChanged(
          *android.view.ActionMode, int, long, boolean)
          */
         public void onItemCheckedStateChanged(ActionMode mode, int position, long id,
                 boolean checked);
     }
 }
	/*
	* Copyright (C) 2013 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.example.android.common.actionbarcompat;

	import android.os.Bundle;
	import android.support.v7.app.ActionBarActivity;
	import android.support.v7.view.ActionMode;
	import android.util.Pair;
	import android.util.SparseBooleanArray;
	import android.view.Menu;
	import android.view.MenuItem;
	import android.view.View;
	import android.widget.AbsListView;
	import android.widget.Adapter;
	import android.widget.AdapterView;
	import android.widget.ListView;

	import java.util.HashSet;

	/**
	* Utilities for handling multiple selection in list views. Contains functionality similar to {@link
	* AbsListView#CHOICE_MODE_MULTIPLE_MODAL} which works with {@link ActionBarActivity} and
	* backward-compatible action bars.
	*/
	public class MultiSelectionUtil {

	/**
	* Attach a Controller to the given <code>listView</code>, <code>activity</code>
	* and <code>listener</code>.
	*
	* @param listView ListView which displays {@link android.widget.Checkable} items.
	* @param activity Activity which contains the ListView.
	* @param listener Listener that will manage the selection mode.
	* @return the attached Controller instance.
	*/
	public static Controller attachMultiSelectionController(final ListView listView,
	final ActionBarActivity activity, final MultiChoiceModeListener listener) {
	return new Controller(listView, activity, listener);
	}

	/**
	* Class which provides functionality similar to {@link AbsListView#CHOICE_MODE_MULTIPLE_MODAL}
	* for the {@link ListView} provided to it. A
	* {@link android.widget.AdapterView.OnItemLongClickListener} is set on the ListView so that
	* when an item is long-clicked an ActionBarCompat Action Mode is started. Once started, a
	* {@link android.widget.AdapterView.OnItemClickListener} is set so that an item click toggles
	* that item's checked state.
	*/
	public static class Controller {

	private final ListView mListView;
	private final ActionBarActivity mActivity;
	private final MultiChoiceModeListener mListener;
	private final Callbacks mCallbacks;

	// Current Action Mode (if there is one)
	private ActionMode mActionMode;

	// Keeps record of any items that should be checked on the next action mode creation
	private HashSet<Pair<Integer, Long>> mItemsToCheck;

	// Reference to the replace OnItemClickListener (so it can be restored later)
	private AdapterView.OnItemClickListener mOldItemClickListener;

	private final Runnable mSetChoiceModeNoneRunnable = new Runnable() {
	@Override
	public void run() {
	mListView.setChoiceMode(AbsListView.CHOICE_MODE_NONE);
	}
	};

	private Controller(ListView listView, ActionBarActivity activity,
	MultiChoiceModeListener listener) {
	mListView = listView;
	mActivity = activity;
	mListener = listener;
	mCallbacks = new Callbacks();

	// We set ourselves as the OnItemLongClickListener so we know when to start
	// an Action Mode
	listView.setOnItemLongClickListener(mCallbacks);
	}

	/**
	* Finish the current Action Mode (if there is one).
	*/
	public void finish() {
	if (mActionMode != null) {
	mActionMode.finish();
	}
	}

	/**
	* This method should be called from your {@link ActionBarActivity} or
	* {@link android.support.v4.app.Fragment Fragment} to allow the controller to restore any
	* instance state.
	*
	* @param savedInstanceState - The state passed to your Activity or Fragment.
	*/
	public void restoreInstanceState(Bundle savedInstanceState) {
	if (savedInstanceState != null) {
	long[] checkedIds = savedInstanceState.getLongArray(getStateKey());
	if (checkedIds != null && checkedIds.length > 0) {
	HashSet<Long> idsToCheckOnRestore = new HashSet<Long>();
	for (long id : checkedIds) {
	idsToCheckOnRestore.add(id);
	}
	tryRestoreInstanceState(idsToCheckOnRestore);
	}
	}
	}

	/**
	* This method should be called from
	* {@link ActionBarActivity#onSaveInstanceState(android.os.Bundle)} or
	* {@link android.support.v4.app.Fragment#onSaveInstanceState(android.os.Bundle)
	* Fragment.onSaveInstanceState(Bundle)} to allow the controller to save its instance
	* state.
	*
	* @param outState - The state passed to your Activity or Fragment.
	*/
	public void saveInstanceState(Bundle outState) {
	if (mActionMode != null && mListView.getAdapter().hasStableIds()) {
	outState.putLongArray(getStateKey(), mListView.getCheckedItemIds());
	}
	}

	// Internal utility methods

	private String getStateKey() {
	return MultiSelectionUtil.class.getSimpleName() + "_" + mListView.getId();
	}

	private void tryRestoreInstanceState(HashSet<Long> idsToCheckOnRestore) {
	if (idsToCheckOnRestore == null \|\| mListView.getAdapter() == null) {
	return;
	}

	boolean idsFound = false;
	Adapter adapter = mListView.getAdapter();
	for (int pos = adapter.getCount() - 1; pos >= 0; pos--) {
	if (idsToCheckOnRestore.contains(adapter.getItemId(pos))) {
	idsFound = true;
	if (mItemsToCheck == null) {
	mItemsToCheck = new HashSet<Pair<Integer, Long>>();
	}
	mItemsToCheck.add(new Pair<Integer, Long>(pos, adapter.getItemId(pos)));
	}
	}

	if (idsFound) {
	// We found some IDs that were checked. Let's now restore the multi-selection
	// state.
	mActionMode = mActivity.startSupportActionMode(mCallbacks);
	}
	}

	/**
	* This class encapsulates all of the callbacks necessary for the controller class.
	*/
	final class Callbacks implements ActionMode.Callback, AdapterView.OnItemClickListener,
	AdapterView.OnItemLongClickListener {

	@Override
	public final boolean onCreateActionMode(ActionMode actionMode, Menu menu) {
	if (mListener.onCreateActionMode(actionMode, menu)) {
	mActionMode = actionMode;
	// Keep a reference to the existing OnItemClickListener so we can restore it
	mOldItemClickListener = mListView.getOnItemClickListener();

	// Set-up the ListView to emulate CHOICE_MODE_MULTIPLE_MODAL
	mListView.setOnItemClickListener(this);
	mListView.setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE);
	mListView.removeCallbacks(mSetChoiceModeNoneRunnable);

	// If there are some items to check, do it now
	if (mItemsToCheck != null) {
	for (Pair<Integer, Long> posAndId : mItemsToCheck) {
	mListView.setItemChecked(posAndId.first, true);
	// Notify the listener that the item has been checked
	mListener.onItemCheckedStateChanged(mActionMode, posAndId.first,
	posAndId.second, true);
	}
	}
	return true;
	}
	return false;
	}

	@Override
	public boolean onPrepareActionMode(ActionMode actionMode, Menu menu) {
	// Proxy listener
	return mListener.onPrepareActionMode(actionMode, menu);
	}

	@Override
	public boolean onActionItemClicked(ActionMode actionMode, MenuItem menuItem) {
	// Proxy listener
	return mListener.onActionItemClicked(actionMode, menuItem);
	}

	@Override
	public void onDestroyActionMode(ActionMode actionMode) {
	mListener.onDestroyActionMode(actionMode);

	// Clear all the checked items
	SparseBooleanArray checkedPositions = mListView.getCheckedItemPositions();
	if (checkedPositions != null) {
	for (int i = 0; i < checkedPositions.size(); i++) {
	mListView.setItemChecked(checkedPositions.keyAt(i), false);
	}
	}

	// Restore the original onItemClickListener
	mListView.setOnItemClickListener(mOldItemClickListener);

	// Clear the Action Mode
	mActionMode = null;

	// Reset the ListView's Choice Mode
	mListView.post(mSetChoiceModeNoneRunnable);
	}

	@Override
	public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
	// Check to see what the new checked state is, and then notify the listener
	final boolean checked = mListView.isItemChecked(position);
	mListener.onItemCheckedStateChanged(mActionMode, position, id, checked);

	boolean hasCheckedItem = checked;

	// Check to see if we have any checked items
	if (!hasCheckedItem) {
	SparseBooleanArray checkedItemPositions = mListView.getCheckedItemPositions();
	if (checkedItemPositions != null) {
	// Iterate through the SparseBooleanArray to see if there is a checked item
	int i = 0;
	while (!hasCheckedItem && i < checkedItemPositions.size()) {
	hasCheckedItem = checkedItemPositions.valueAt(i++);
	}
	}
	}

	// If we don't have any checked items, finish the action mode
	if (!hasCheckedItem) {
	mActionMode.finish();
	}
	}

	@Override
	public boolean onItemLongClick(AdapterView<?> adapterView, View view, int position,
	long id) {
	// If we already have an action mode started return false
	// (onItemClick will be called anyway)
	if (mActionMode != null) {
	return false;
	}

	mItemsToCheck = new HashSet<Pair<Integer, Long>>();
	mItemsToCheck.add(new Pair<Integer, Long>(position, id));
	mActionMode = mActivity.startSupportActionMode(this);
	return true;
	}
	}
	}

	/**
	* @see android.widget.AbsListView.MultiChoiceModeListener
	*/
	public static interface MultiChoiceModeListener extends ActionMode.Callback {

	/**
	* @see android.widget.AbsListView.MultiChoiceModeListener#onItemCheckedStateChanged(
	*android.view.ActionMode, int, long, boolean)
	*/
	public void onItemCheckedStateChanged(ActionMode mode, int position, long id,
	boolean checked);
	}
	}