datetimepicker/time/TimePickerDialog.java

/*
 * 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.android.datetimepicker.time;

import android.annotation.SuppressLint;
import android.app.ActionBar.LayoutParams;
import android.app.DialogFragment;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyCharacterMap;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.android.datetimepicker.R;

import com.android.datetimepicker.time.RadialPickerLayout.OnValueSelectedListener;
import com.android.datetimepicker.Utils;

import java.text.DateFormatSymbols;
import java.util.ArrayList;
import java.util.Locale;

/**
 * Dialog to set a time.
 */
public class TimePickerDialog extends DialogFragment implements OnValueSelectedListener{
    private static final String TAG = "TimePickerDialog";

    private static final String KEY_HOUR_OF_DAY = "hour_of_day";
    private static final String KEY_MINUTE = "minute";
    private static final String KEY_IS_24_HOUR_VIEW = "is_24_hour_view";
    private static final String KEY_CURRENT_ITEM_SHOWING = "current_item_showing";
    private static final String KEY_IN_KB_MODE = "in_kb_mode";
    private static final String KEY_TYPED_TIMES = "typed_times";

    public static final int HOUR_INDEX = 0;
    public static final int MINUTE_INDEX = 1;
    public static final int AMPM_INDEX = 2; // NOT a real index for the purpose of what's showing.
    public static final int ENABLE_PICKER_INDEX = 3; // Also NOT a real index, just used for KB mode.
    public static final int AM = 0;
    public static final int PM = 1;

    private OnTimeSetListener mCallback;

    private TextView mDoneButton;
    private TextView mHourView;
    private TextView mMinuteView;
    private TextView mAmPmTextView;
    private View mAmPmHitspace;
    private RadialPickerLayout mTimePicker;

    private int mBlue;
    private int mBlack;
    private String mAmText;
    private String mPmText;

    private boolean mAllowAutoAdvance;
    private int mInitialHourOfDay;
    private int mInitialMinute;
    private boolean mIs24HourMode;

    // For hardware IME input.
    private char mPlaceholderText;
    private String mDoublePlaceholderText;
    private boolean mInKbMode;
    private ArrayList<Integer> mTypedTimes;
    private Node mLegalTimesTree;
    private int mAmKeyCode;
    private int mPmKeyCode;

    // Accessibility strings.
    private String mHourPickerDescription;
    private String mSelectHours;
    private String mMinutePickerDescription;
    private String mSelectMinutes;

    /**
     * The callback interface used to indicate the user is done filling in
     * the time (they clicked on the 'Set' button).
     */
    public interface OnTimeSetListener {

        /**
         * @param view The view associated with this listener.
         * @param hourOfDay The hour that was set.
         * @param minute The minute that was set.
         */
        void onTimeSet(RadialPickerLayout view, int hourOfDay, int minute);
    }

    public TimePickerDialog() {
        // Empty constructor required for dialog fragment.
    }

    public TimePickerDialog(Context context, int theme, OnTimeSetListener callback,
            int hourOfDay, int minute, boolean is24HourMode) {
        // Empty constructor required for dialog fragment.
    }

    public static TimePickerDialog newInstance(OnTimeSetListener callback,
            int hourOfDay, int minute, boolean is24HourMode) {
        TimePickerDialog ret = new TimePickerDialog();
        ret.initialize(callback, hourOfDay, minute, is24HourMode);
        return ret;
    }

    public void initialize(OnTimeSetListener callback,
            int hourOfDay, int minute, boolean is24HourMode) {
        mCallback = callback;

        mInitialHourOfDay = hourOfDay;
        mInitialMinute = minute;
        mIs24HourMode = is24HourMode;
        mInKbMode = false;
    }

    public void setOnTimeSetListener(OnTimeSetListener callback) {
        mCallback = callback;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState != null && savedInstanceState.containsKey(KEY_HOUR_OF_DAY)
                    && savedInstanceState.containsKey(KEY_MINUTE)
                    && savedInstanceState.containsKey(KEY_IS_24_HOUR_VIEW)) {
            mInitialHourOfDay = savedInstanceState.getInt(KEY_HOUR_OF_DAY);
            mInitialMinute = savedInstanceState.getInt(KEY_MINUTE);
            mIs24HourMode = savedInstanceState.getBoolean(KEY_IS_24_HOUR_VIEW);
            mInKbMode = savedInstanceState.getBoolean(KEY_IN_KB_MODE);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);

        View view = inflater.inflate(R.layout.time_picker_dialog, null);
        KeyboardListener keyboardListener = new KeyboardListener();
        view.findViewById(R.id.time_picker_dialog).setOnKeyListener(keyboardListener);

        Resources res = getResources();
        mHourPickerDescription = res.getString(R.string.hour_picker_description);
        mSelectHours = res.getString(R.string.select_hours);
        mMinutePickerDescription = res.getString(R.string.minute_picker_description);
        mSelectMinutes = res.getString(R.string.select_minutes);
        mBlue = res.getColor(R.color.blue);
        mBlack = res.getColor(R.color.black_80);

        mHourView = (TextView) view.findViewById(R.id.hours);
        mHourView.setOnKeyListener(keyboardListener);
        mMinuteView = (TextView) view.findViewById(R.id.minutes);
        mMinuteView.setOnKeyListener(keyboardListener);
        mAmPmTextView = (TextView) view.findViewById(R.id.ampm_label);
        mAmPmTextView.setOnKeyListener(keyboardListener);
        String[] amPmTexts = new DateFormatSymbols().getAmPmStrings();
        mAmText = amPmTexts[0];
        mPmText = amPmTexts[1];

        mTimePicker = (RadialPickerLayout) view.findViewById(R.id.time_picker);
        mTimePicker.setOnValueSelectedListener(this);
        mTimePicker.setOnKeyListener(keyboardListener);
        mTimePicker.initialize(getActivity(), mInitialHourOfDay, mInitialMinute, mIs24HourMode);
        int currentItemShowing = HOUR_INDEX;
        if (savedInstanceState != null &&
                savedInstanceState.containsKey(KEY_CURRENT_ITEM_SHOWING)) {
            currentItemShowing = savedInstanceState.getInt(KEY_CURRENT_ITEM_SHOWING);
        }
        setCurrentItemShowing(currentItemShowing, false);
        mTimePicker.invalidate();

        mHourView.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                setCurrentItemShowing(HOUR_INDEX, true);
                mTimePicker.tryVibrate();
            }
        });
        mMinuteView.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                setCurrentItemShowing(MINUTE_INDEX, true);
                mTimePicker.tryVibrate();
            }
        });

        mDoneButton = (TextView) view.findViewById(R.id.done_button);
        mDoneButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mInKbMode && isTypedTimeFullyLegal()) {
                    finishKbMode(false);
                } else {
                    mTimePicker.tryVibrate();
                }
                if (mCallback != null) {
                    mCallback.onTimeSet(mTimePicker,
                            mTimePicker.getHours(), mTimePicker.getMinutes());
                }
                dismiss();
            }
        });
        mDoneButton.setOnKeyListener(keyboardListener);

        mAmPmHitspace = view.findViewById(R.id.ampm_hitspace);
        if (mIs24HourMode) {
            mAmPmTextView.setVisibility(View.GONE);

            RelativeLayout.LayoutParams paramsSeparator = new RelativeLayout.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            paramsSeparator.addRule(RelativeLayout.CENTER_IN_PARENT);
            TextView separatorView = (TextView) view.findViewById(R.id.separator);
            separatorView.setLayoutParams(paramsSeparator);
        } else {
            mAmPmTextView.setVisibility(View.VISIBLE);
            updateAmPmDisplay(mInitialHourOfDay < 12? AM : PM);
            mAmPmHitspace.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    mTimePicker.tryVibrate();
                    int amOrPm = mTimePicker.getIsCurrentlyAmOrPm();
                    if (amOrPm == AM) {
                        amOrPm = PM;
                    } else if (amOrPm == PM){
                        amOrPm = AM;
                    }
                    updateAmPmDisplay(amOrPm);
                    mTimePicker.setAmOrPm(amOrPm);
                }
            });
        }

        mAllowAutoAdvance = true;
        setHour(mInitialHourOfDay);
        setMinute(mInitialMinute);

        mDoublePlaceholderText = res.getString(R.string.time_placeholder);
        mPlaceholderText = mDoublePlaceholderText.charAt(0);
        mAmKeyCode = mPmKeyCode = -1;
        generateLegalTimesTree();
        if (mInKbMode) {
            mTypedTimes = savedInstanceState.getIntegerArrayList(KEY_TYPED_TIMES);
            tryStartingKbMode(-1);
            mHourView.invalidate();
        } else if (mTypedTimes == null) {
            mTypedTimes = new ArrayList<Integer>();
        }

        return view;
    }

    private void updateAmPmDisplay(int amOrPm) {
        if (amOrPm == AM) {
            mAmPmTextView.setText(mAmText);
            tryAccessibilityAnnounce(mAmText);
            mAmPmHitspace.setContentDescription(mAmText);
        } else if (amOrPm == PM){
            mAmPmTextView.setText(mPmText);
            tryAccessibilityAnnounce(mPmText);
            mAmPmHitspace.setContentDescription(mPmText);
        } else {
            mAmPmTextView.setText(mDoublePlaceholderText);
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        if (mTimePicker != null) {
            outState.putInt(KEY_HOUR_OF_DAY, mTimePicker.getHours());
            outState.putInt(KEY_MINUTE, mTimePicker.getMinutes());
            outState.putBoolean(KEY_IS_24_HOUR_VIEW, mIs24HourMode);
            outState.putInt(KEY_CURRENT_ITEM_SHOWING, mTimePicker.getCurrentItemShowing());
            outState.putBoolean(KEY_IN_KB_MODE, mInKbMode);
            if (mInKbMode) {
                outState.putIntegerArrayList(KEY_TYPED_TIMES, mTypedTimes);
            }
        }
    }

    @Override
    public void onValueSelected(int pickerIndex, int newValue, boolean autoAdvance) {
        if (pickerIndex == HOUR_INDEX) {
            setHour(newValue);
            if (mAllowAutoAdvance && autoAdvance) {
                setCurrentItemShowing(MINUTE_INDEX, true);
            }
        } else if (pickerIndex == MINUTE_INDEX){
            setMinute(newValue);
        } else if (pickerIndex == AMPM_INDEX) {
            updateAmPmDisplay(newValue);
        } else if (pickerIndex == ENABLE_PICKER_INDEX) {
            if (!isTypedTimeFullyLegal()) {
                mTypedTimes.clear();
            }
            finishKbMode(true);
        }
    }

    private void setHour(int value) {
        String format;
        if (mIs24HourMode) {
            format = "%02d";
        } else {
            format = "%d";
            value = value % 12;
            if (value == 0) {
                value = 12;
            }
        }

        CharSequence text = String.format(format, value);
        tryAccessibilityAnnounce(text);
        mHourView.setText(text);
    }

    private void setMinute(int value) {
        if (value == 60) {
            value = 0;
        }
        CharSequence text = String.format(Locale.getDefault(), "%02d", value);
        tryAccessibilityAnnounce(text);
        mMinuteView.setText(text);
    }

    private void setCurrentItemShowing(int index, boolean animate) {
        mTimePicker.setCurrentItemShowing(index, animate);

        if (index == HOUR_INDEX) {
            int hours = mTimePicker.getHours();
            if (!mIs24HourMode) {
                hours = hours % 12;
            }
            mTimePicker.setContentDescription(mHourPickerDescription+": "+hours);
            tryAccessibilityAnnounce(mSelectHours);
        } else {
            int minutes = mTimePicker.getMinutes();
            mTimePicker.setContentDescription(mMinutePickerDescription+": "+minutes);
            tryAccessibilityAnnounce(mSelectMinutes);
        }

        int hourColor = (index == HOUR_INDEX)? mBlue : mBlack;
        int minuteColor = (index == MINUTE_INDEX)? mBlue : mBlack;
        mHourView.setTextColor(hourColor);
        mMinuteView.setTextColor(minuteColor);
    }

    @SuppressLint("NewApi")
    private void tryAccessibilityAnnounce(CharSequence text) {
        if (Utils.isJellybeanOrLater() && mTimePicker != null && text != null) {
            mTimePicker.announceForAccessibility(text);
        }
    }

    private boolean processKeyUp(int keyCode) {
        if (keyCode == KeyEvent.KEYCODE_ESCAPE || keyCode == KeyEvent.KEYCODE_BACK) {
            dismiss();
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_TAB) {
            if(mInKbMode) {
                if (isTypedTimeFullyLegal()) {
                    finishKbMode(true);
                }
                return true;
            }
        } else if (keyCode == KeyEvent.KEYCODE_ENTER) {
            if (mInKbMode) {
                if (!isTypedTimeFullyLegal()) {
                    return true;
                }
                finishKbMode(false);
            }
            if (mCallback != null) {
                mCallback.onTimeSet(mTimePicker,
                        mTimePicker.getHours(), mTimePicker.getMinutes());
            }
            dismiss();
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_DEL) {
            if (mInKbMode) {
                if (!mTypedTimes.isEmpty()) {
                    deleteLastTypedKey();
                    updateDisplay(true);
                }
            }
        } else if (keyCode == KeyEvent.KEYCODE_0 || keyCode == KeyEvent.KEYCODE_1
                || keyCode == KeyEvent.KEYCODE_2 || keyCode == KeyEvent.KEYCODE_3
                || keyCode == KeyEvent.KEYCODE_4 || keyCode == KeyEvent.KEYCODE_5
                || keyCode == KeyEvent.KEYCODE_6 || keyCode == KeyEvent.KEYCODE_7
                || keyCode == KeyEvent.KEYCODE_8 || keyCode == KeyEvent.KEYCODE_9
                || (!mIs24HourMode &&
                        (keyCode == getAmOrPmKeyCode(AM) || keyCode == getAmOrPmKeyCode(PM)))) {
            if (!mInKbMode) {
                if (mTimePicker == null) {
                    // Something's wrong, because time picker should definitely not be null.
                    Log.e(TAG, "Unable to initiate keyboard mode, TimePicker was null.");
                    return true;
                }
                mTypedTimes.clear();
                tryStartingKbMode(keyCode);
                return true;
            }
            // We're already in keyboard mode.
            if (addKeyIfLegal(keyCode)) {
                updateDisplay(false);
            }
            return true;
        }
        return false;
    }

    private void tryStartingKbMode(int keyCode) {
        if (mTimePicker.trySettingInputEnabled(false) && (keyCode == -1 || addKeyIfLegal(keyCode))) {
            mInKbMode = true;
            mDoneButton.setEnabled(false);
            updateDisplay(false);
        }
    }

    private boolean addKeyIfLegal(int keyCode) {
        // If we're in 24hour mode, we'll need to check if the input is full. If in AM/PM mode,
        // we'll need to see if AM/PM have been typed.
        if ((mIs24HourMode && mTypedTimes.size() == 4) ||
                (!mIs24HourMode && isTypedTimeFullyLegal())) {
            return false;
        }

        mTypedTimes.add(keyCode);
        if (!isTypedTimeLegalSoFar()) {
            deleteLastTypedKey();
            return false;
        }

        // Automatically fill in 0's if AM or PM was legally entered.
        if (isTypedTimeFullyLegal()) {
            if (!mIs24HourMode && mTypedTimes.size() <= 3) {
                mTypedTimes.add(mTypedTimes.size() - 1, KeyEvent.KEYCODE_0);
                mTypedTimes.add(mTypedTimes.size() - 1, KeyEvent.KEYCODE_0);
            }
            mDoneButton.setEnabled(true);
        }

        return true;
    }

    private boolean isTypedTimeLegalSoFar() {
        Node node = mLegalTimesTree;
        for (int keyCode : mTypedTimes) {
            node = node.canReach(keyCode);
            if (node == null) {
                return false;
            }
        }
        return true;
    }

    private boolean isTypedTimeFullyLegal() {
        // The time is legal if it contains an AM or PM, as those can only be legally added at
        // specific times based on the tree's algorithm.
        if (mIs24HourMode) {
            // getEnteredTime() will ONLY call isTypedTimeFullyLegal() when NOT in 24hour mode.
            int[] values = getEnteredTime(null);
            return (values[0] >= 0 && values[1] >= 0 && values[1] < 60);
        } else {
            return (mTypedTimes.contains(getAmOrPmKeyCode(AM)) ||
                    mTypedTimes.contains(getAmOrPmKeyCode(PM)));
        }
    }

    private void deleteLastTypedKey() {
        mTypedTimes.remove(mTypedTimes.size() - 1);
        if (!isTypedTimeFullyLegal()) {
            mDoneButton.setEnabled(false);
        }
    }

    private void finishKbMode(boolean changeDisplays) {
        mInKbMode = false;
        if (!mTypedTimes.isEmpty()) {
            int values[] = getEnteredTime(null);
            mTimePicker.setTime(values[0], values[1]);
            if (!mIs24HourMode) {
                mTimePicker.setAmOrPm(values[2]);
            }
            mTypedTimes.clear();
        }
        if (changeDisplays) {
            updateDisplay(false);
            mTimePicker.trySettingInputEnabled(true);
        }
    }

    private void updateDisplay(boolean allowEmpty) {
        if (!allowEmpty && mTypedTimes.isEmpty()) {
            int hour = mTimePicker.getHours();
            int minute = mTimePicker.getMinutes();
            setHour(hour);
            setMinute(minute);
            if (!mIs24HourMode) {
                updateAmPmDisplay(hour < 12? AM : PM);
            }
            setCurrentItemShowing(mTimePicker.getCurrentItemShowing(), true);
            mDoneButton.setEnabled(true);
        } else {
            Boolean[] enteredZeros = {false, false};
            int[] values = getEnteredTime(enteredZeros);
            String hourFormat = enteredZeros[0]? "%02d" : "%2d";
            String minuteFormat = (enteredZeros[1])? "%02d" : "%2d";
            String hourStr = (values[0] == -1)? mDoublePlaceholderText :
                String.format(hourFormat, values[0]).replace(' ', mPlaceholderText);
            String minuteStr = (values[1] == -1)? mDoublePlaceholderText :
                String.format(minuteFormat, values[1]).replace(' ', mPlaceholderText);
            mHourView.setText(hourStr);
            mHourView.setTextColor(mBlack);
            mMinuteView.setText(minuteStr);
            mMinuteView.setTextColor(mBlack);
            if (!mIs24HourMode) {
                updateAmPmDisplay(values[2]);
            }
        }
    }

    private int getValFromKeyCode(int keyCode) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_0:
                return 0;
            case KeyEvent.KEYCODE_1:
                return 1;
            case KeyEvent.KEYCODE_2:
                return 2;
            case KeyEvent.KEYCODE_3:
                return 3;
            case KeyEvent.KEYCODE_4:
                return 4;
            case KeyEvent.KEYCODE_5:
                return 5;
            case KeyEvent.KEYCODE_6:
                return 6;
            case KeyEvent.KEYCODE_7:
                return 7;
            case KeyEvent.KEYCODE_8:
                return 8;
            case KeyEvent.KEYCODE_9:
                return 9;
            default:
                return -1;
        }
    }

    private int[] getEnteredTime(Boolean[] enteredZeros) {
        int amOrPm = -1;
        int startIndex = 1;
        if (!mIs24HourMode && isTypedTimeFullyLegal()) {
            int keyCode = mTypedTimes.get(mTypedTimes.size() - 1);
            if (keyCode == getAmOrPmKeyCode(AM)) {
                amOrPm = AM;
            } else if (keyCode == getAmOrPmKeyCode(PM)){
                amOrPm = PM;
            }
            startIndex = 2;
        }
        int minute = -1;
        int hour = -1;
        for (int i = startIndex; i <= mTypedTimes.size(); i++) {
            int val = getValFromKeyCode(mTypedTimes.get(mTypedTimes.size() - i));
            if (i == startIndex) {
                minute = val;
            } else if (i == startIndex+1) {
                minute += 10*val;
                if (enteredZeros != null && val == 0) {
                    enteredZeros[1] = true;
                }
            } else if (i == startIndex+2) {
                hour = val;
            } else if (i == startIndex+3) {
                hour += 10*val;
                if (enteredZeros != null && val == 0) {
                    enteredZeros[0] = true;
                }
            }
        }

        int[] ret = {hour, minute, amOrPm};
        return ret;
    }

    private int getAmOrPmKeyCode(int amOrPm) {
        // Cache the codes.
        if (mAmKeyCode == -1 || mPmKeyCode == -1) {
            // Find the first character in the AM/PM text that is unique.
            KeyCharacterMap kcm = KeyCharacterMap.load(KeyCharacterMap.VIRTUAL_KEYBOARD);
            char amChar;
            char pmChar;
            for (int i = 0; i < Math.max(mAmText.length(), mPmText.length()); i++) {
                amChar = mAmText.toLowerCase(Locale.getDefault()).charAt(i);
                pmChar = mPmText.toLowerCase(Locale.getDefault()).charAt(i);
                if (amChar != pmChar) {
                    KeyEvent[] events = kcm.getEvents(new char[]{amChar, pmChar});
                    // There should be 4 events: a down and up for both AM and PM.
                    if (events != null && events.length == 4) {
                        mAmKeyCode = events[0].getKeyCode();
                        mPmKeyCode = events[2].getKeyCode();
                        Log.d(TAG, "am char: "+amChar+" keycode: "+mAmKeyCode);
                        Log.d(TAG, "pm char: "+pmChar+" keycode: "+mPmKeyCode);
                    } else {
                        Log.d(TAG, "am char: "+amChar+" keycode: "+mAmKeyCode);
                        Log.d(TAG, "pm char: "+pmChar+" keycode: "+mPmKeyCode);
                        if (events != null) {
                            for (int j = 0; j < events.length; j++) {
                                Log.d(TAG, "event code: "+events[j].getKeyCode()+" events: "+events[j]);
                            }
                        }
                        Log.e(TAG, "Unable to find keycodes for AM and PM.");
                    }
                    break;
                }
            }
        }
        if (amOrPm == AM) {
            return mAmKeyCode;
        } else if (amOrPm == PM) {
            return mPmKeyCode;
        }

        return -1;
    }

    private void generateLegalTimesTree() {
        // Create a quick cache of numbers to their keycodes.
        int k0 = KeyEvent.KEYCODE_0;
        int k1 = KeyEvent.KEYCODE_1;
        int k2 = KeyEvent.KEYCODE_2;
        int k3 = KeyEvent.KEYCODE_3;
        int k4 = KeyEvent.KEYCODE_4;
        int k5 = KeyEvent.KEYCODE_5;
        int k6 = KeyEvent.KEYCODE_6;
        int k7 = KeyEvent.KEYCODE_7;
        int k8 = KeyEvent.KEYCODE_8;
        int k9 = KeyEvent.KEYCODE_9;

        // The root of the tree doesn't contain any numbers.
        mLegalTimesTree = new Node();
        if (mIs24HourMode) {
            // We'll be re-using these nodes, so we'll save them.
            Node minuteFirstDigit = new Node(k0, k1, k2, k3, k4, k5);
            Node minuteSecondDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
            // The first digit must be followed by the second digit.
            minuteFirstDigit.addChild(minuteSecondDigit);

            // The first digit may be 0-1.
            Node firstDigit = new Node(k0, k1);
            mLegalTimesTree.addChild(firstDigit);

            // When the first digit is 0-1, the second digit may be 0-5.
            Node secondDigit = new Node(k0, k1, k2, k3, k4, k5);
            firstDigit.addChild(secondDigit);
            // We may now be followed by the first minute digit. E.g. 00:09, 15:58.
            secondDigit.addChild(minuteFirstDigit);

            // When the first digit is 0-1, and the second digit is 0-5, the third digit may be 6-9.
            Node thirdDigit = new Node(k6, k7, k8, k9);
            // The time must now be finished. E.g. 0:55, 1:08.
            secondDigit.addChild(thirdDigit);

            // When the first digit is 0-1, the second digit may be 6-9.
            secondDigit = new Node(k6, k7, k8, k9);
            firstDigit.addChild(secondDigit);
            // We must now be followed by the first minute digit. E.g. 06:50, 18:20.
            secondDigit.addChild(minuteFirstDigit);

            // The first digit may be 2.
            firstDigit = new Node(k2);
            mLegalTimesTree.addChild(firstDigit);

            // When the first digit is 2, the second digit may be 0-3.
            secondDigit = new Node(k0, k1, k2, k3);
            firstDigit.addChild(secondDigit);
            // We must now be followed by the first minute digit. E.g. 20:50, 23:09.
            secondDigit.addChild(minuteFirstDigit);

            // When the first digit is 2, the second digit may be 4-5.
            secondDigit = new Node(k4, k5);
            firstDigit.addChild(secondDigit);
            // We must now be followd by the last minute digit. E.g. 2:40, 2:53.
            secondDigit.addChild(minuteSecondDigit);

            // The first digit may be 3-9.
            firstDigit = new Node(k3, k4, k5, k6, k7, k8, k9);
            mLegalTimesTree.addChild(firstDigit);
            // We must now be followed by the first minute digit. E.g. 3:57, 8:12.
            firstDigit.addChild(minuteFirstDigit);
        } else {
            // We'll need to use the AM/PM node a lot.
            // Set up AM and PM to respond to "a" and "p".
            Node ampm = new Node(getAmOrPmKeyCode(AM), getAmOrPmKeyCode(PM));

            // The first hour digit may be 1.
            Node firstDigit = new Node(k1);
            mLegalTimesTree.addChild(firstDigit);
            // We'll allow quick input of on-the-hour times. E.g. 1pm.
            firstDigit.addChild(ampm);

            // When the first digit is 1, the second digit may be 0-2.
            Node secondDigit = new Node(k0, k1, k2);
            firstDigit.addChild(secondDigit);
            // Also for quick input of on-the-hour times. E.g. 10pm, 12am.
            secondDigit.addChild(ampm);

            // When the first digit is 1, and the second digit is 0-2, the third digit may be 0-5.
            Node thirdDigit = new Node(k0, k1, k2, k3, k4, k5);
            secondDigit.addChild(thirdDigit);
            // The time may be finished now. E.g. 1:02pm, 1:25am.
            thirdDigit.addChild(ampm);

            // When the first digit is 1, the second digit is 0-2, and the third digit is 0-5,
            // the fourth digit may be 0-9.
            Node fourthDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
            thirdDigit.addChild(fourthDigit);
            // The time must be finished now. E.g. 10:49am, 12:40pm.
            fourthDigit.addChild(ampm);

            // When the first digit is 1, and the second digit is 0-2, the third digit may be 6-9.
            thirdDigit = new Node(k6, k7, k8, k9);
            secondDigit.addChild(thirdDigit);
            // The time must be finished now. E.g. 1:08am, 1:26pm.
            thirdDigit.addChild(ampm);

            // When the first digit is 1, the second digit may be 3-5.
            secondDigit = new Node(k3, k4, k5);
            firstDigit.addChild(secondDigit);

            // When the first digit is 1, and the second digit is 3-5, the third digit may be 0-9.
            thirdDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
            secondDigit.addChild(thirdDigit);
            // The time must be finished now. E.g. 1:39am, 1:50pm.
            thirdDigit.addChild(ampm);

            // The hour digit may be 2-9.
            firstDigit = new Node(k2, k3, k4, k5, k6, k7, k8, k9);
            mLegalTimesTree.addChild(firstDigit);
            // We'll allow quick input of on-the-hour-times. E.g. 2am, 5pm.
            firstDigit.addChild(ampm);

            // When the first digit is 2-9, the second digit may be 0-5.
            secondDigit = new Node(k0, k1, k2, k3, k4, k5);
            firstDigit.addChild(secondDigit);

            // When the first digit is 2-9, and the second digit is 0-5, the third digit may be 0-9.
            thirdDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
            secondDigit.addChild(thirdDigit);
            // The time must be finished now. E.g. 2:57am, 9:30pm.
            thirdDigit.addChild(ampm);
        }
    }

    private class Node {
        private int[] mLegalKeys;
        private ArrayList<Node> mChildren;

        public Node(int... legalKeys) {
            mLegalKeys = legalKeys;
            mChildren = new ArrayList<Node>();
        }

        public void addChild(Node child) {
            mChildren.add(child);
        }

        public boolean containsKey(int key) {
            for (int i = 0; i < mLegalKeys.length; i++) {
                if (mLegalKeys[i] == key) {
                    return true;
                }
            }
            return false;
        }

        public Node canReach(int key) {
            if (mChildren == null) {
                return null;
            }
            for (Node child : mChildren) {
                if (child.containsKey(key)) {
                    return child;
                }
            }
            return null;
        }
    }

    private class KeyboardListener implements OnKeyListener {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_UP) {
                return processKeyUp(keyCode);
            }
            return false;
        }
    }
}