ListPreferenceMultiSelect.java

package com.thomasdh.roosterpgplus.CustomUI;

import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.content.res.TypedArray;
import android.preference.ListPreference;
import android.support.annotation.NonNull;
import android.util.AttributeSet;
import android.widget.ListView;

import com.thomasdh.roosterpgplus.R;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

public class ListPreferenceMultiSelect extends ListPreference {
    private static final String DEFAULT_SEPARATOR = "OV=I=XseparatorX=I=VO";
    private final String separator;
    private String checkAllKey = null;
    private boolean[] mClickedDialogEntryIndices;

    // Constructor
    public ListPreferenceMultiSelect(Context context, AttributeSet attrs) {
        super(context, attrs);
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ListPreferenceMultiSelect);
        if (a != null) {
            checkAllKey = a.getString(R.styleable.ListPreferenceMultiSelect_checkAll);
        }
        String s = a != null ? a.getString(R.styleable.ListPreferenceMultiSelect_separator) : null;
        if (s != null) {
            separator = s;
        } else {
            separator = DEFAULT_SEPARATOR;
        }
        // Initialize the array of boolean to the same size as number of entries
        CharSequence[] entries = getEntries();
        mClickedDialogEntryIndices = new boolean[entries != null ? entries.length : 0];
    }

    // Credits to kurellajunior on this post http://snippets.dzone.com/posts/show/91
    protected static String join(Iterable<?> pColl, String separator) {
        Iterator<?> oIter;
        if (pColl == null || !(oIter = pColl.iterator()).hasNext())
            return "";
        StringBuilder oBuilder = new StringBuilder(String.valueOf(oIter.next()));
        while (oIter.hasNext())
            oBuilder.append(separator).append(oIter.next());
        return oBuilder.toString();
    }


    public void setEntries(CharSequence[] entries, boolean[] enabled) {
        setEntries(entries);
        mClickedDialogEntryIndices = enabled;
    }

    @Override
    public void setEntries(CharSequence[] entries) {
        super.setEntries(entries);
        // Initialize the array of boolean to the same size as number of entries
        mClickedDialogEntryIndices = new boolean[entries.length];
    }

    @Override
    protected void onPrepareDialogBuilder(@NonNull Builder builder) {
        CharSequence[] entries = getEntries();
        CharSequence[] entryValues = getEntryValues();
        if (entries == null || entryValues == null || entries.length != entryValues.length) {
            throw new IllegalStateException(
                    "ListPreference requires an entries array and an entryValues array which are both the same length");
        }

        restoreCheckedEntries();
        builder.setMultiChoiceItems(entries, mClickedDialogEntryIndices,
                (dialog, which, val) -> {
                    if (isCheckAllValue(which)) {
                        checkAll(dialog, val);
                    }
                    mClickedDialogEntryIndices[which] = val;
                }
        );
    }

    private boolean isCheckAllValue(int which) {
        CharSequence[] entryValues = getEntryValues();
        return checkAllKey != null && entryValues[which].equals(checkAllKey);
    }

    private void checkAll(DialogInterface dialog, boolean val) {
        ListView lv = ((AlertDialog) dialog).getListView();
        int size = lv.getCount();
        for (int i = 0; i < size; i++) {
            lv.setItemChecked(i, val);
            mClickedDialogEntryIndices[i] = val;
        }
    }

    public String[] parseStoredValue(CharSequence val) {
        if ("".equals(val)) {
            return null;
        } else {
            return ((String) val).split(separator);
        }
    }

    private void restoreCheckedEntries() {
        CharSequence[] entryValues = getEntryValues();

        // Explode the string read in sharedpreferences
        String[] vals = parseStoredValue(getValue());

        if (vals != null) {
            List<String> valuesList = Arrays.asList(vals);
//        	for ( int j=0; j<vals.length; j++ ) {
//
//        		String val = vals[j].trim();
            for (int i = 0; i < entryValues.length; i++) {
                CharSequence entry = entryValues[i];
                if (valuesList.contains(entry)) {
                    mClickedDialogEntryIndices[i] = true;
                }
            }
//        	}
        }
    }


    @Override
    protected void onDialogClosed(boolean positiveResult) {
//        super.onDialogClosed(positiveResult);
        ArrayList<String> values = new ArrayList<>();

        CharSequence[] entryValues = getEntryValues();
        if (positiveResult && entryValues != null) {
            for (int i = 0; i < entryValues.length; i++) {
                if (mClickedDialogEntryIndices[i]) {
                    // Don't save the state of check all option - if any
                    String val = (String) entryValues[i];
                    if (checkAllKey == null || !val.equals(checkAllKey)) {
                        values.add(val);
                    }
                }
            }

            if (callChangeListener(values)) {
                setValue(join(values, separator));
            }
        }
    }
}