ListPreferenceMultiSelect.java

/*
Copyright (C) 2012, Dirk Trossen, airs@dirk-trossen.de

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation as version 2.1 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
*/
package com.airs.helper;

import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.preference.ListPreference;
import android.util.AttributeSet;

/**
 * 
 * @author declanshanaghy
 * http://blog.350nice.com/wp/archives/240
 * MultiChoice Preference Widget for Android
 * Adjusted for use in AIRS
 *
 */
public class ListPreferenceMultiSelect extends ListPreference
{
	private String separator = "::";
	private boolean[] mClickedDialogEntryIndices;

	/**
	 * Constructor
	 * @param context Reference to the calling {@link android.content.Context}
	 */
    public ListPreferenceMultiSelect(Context context) 
    {
        this(context, null);        
    }
    
	/** 
	 * Constructor
	 * @param context Reference to the calling {@link android.content.Context}
	 * @param attrs Reference to the {@link android.util.AttributeSet} of the layout
	 */
	public ListPreferenceMultiSelect(Context context, AttributeSet attrs) 
	{
        super(context, attrs);
        mClickedDialogEntryIndices = new boolean[getEntries().length];
    }
	
    
	/**
	 * Set the entries being shown in the multi select list
	 */
	@Override
    public void setEntries(CharSequence[] entries) 
	{
    	super.setEntries(entries);
    	if (entries.length != 0)
	        mClickedDialogEntryIndices = new boolean[entries.length];
    }

	/**
	 * Function called by the system when preparing the Preference
	 * @param builder Reference to the {@link android.app.AlertDialog.Builder} being used
	 */
    @Override
    protected void onPrepareDialogBuilder(Builder builder) 
    {
    	CharSequence[] entries = getEntries();
    	CharSequence[] entryValues = getEntryValues();
    	
    	// are there any entries?
        if (entries == null || entryValues == null || entries.length != entryValues.length ) 
        {
            throw new IllegalStateException(
                    "ListPreference requires an entries array and an entryValues array of equal length");
        }

        restoreCheckedEntries();
        builder.setMultiChoiceItems(entries, mClickedDialogEntryIndices, 
                new DialogInterface.OnMultiChoiceClickListener() 
        		{
					public void onClick(DialogInterface dialog, int which, boolean val) 
					{
						mClickedDialogEntryIndices[which] = val;
					}
        		});
    }
        
    /**
     * Goes through the list of entries and sets the checkmarks according to the persistent values
     */
    private void restoreCheckedEntries() 
    {
    	int i, j;
    	// get stored key
    	String value = getValue();
    	if (value == null)
    		return;
    	
    	CharSequence[] entryValues = getEntryValues();
    	
    	// Explode the string read in sharedpreferences
    	String[] vals = value.split(separator);
    	
    	if ( vals.length != 0 ) 
        	for (i=0; i<entryValues.length; i++ ) 
        	{
        		String entry = entryValues[i].toString();
        		
        		for (j=0;j<vals.length;j++)
        			if ( vals[j].compareTo(entry) == 0 ) 
        				mClickedDialogEntryIndices[i] = true;
        	}
    }

    /**
     * Called when dialog is closed by the user
     * @param positiveResult has the positive button been pressed (true) or not (false)
     */
	@Override
    protected void onDialogClosed(boolean positiveResult) 
	{
		StringBuffer values = new StringBuffer();
		String valueString;
		boolean first = false;
        
    	CharSequence[] entryValues = getEntryValues();
        if (positiveResult == true && entryValues != null) 
        {
        	for ( int i=0; i<entryValues.length; i++ ) 
        		if ( mClickedDialogEntryIndices[i] == true ) 
        		{
        			// append separator after first one has been written
        			if (first == true)
        				values.append(separator);
        			
        			values.append((String) entryValues[i]);
        			first = true;
        		}

        	valueString = values.toString();
        	
            if (callChangeListener(valueString) == true) 
        		setValue(valueString);
        }
    }
}