ReadMiNotes/代码标注/DateTimePicker.java

/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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 net.micode.notes.ui;

import java.text.DateFormatSymbols;
import java.util.Calendar;

import net.micode.notes.R;


import android.content.Context;
import android.text.format.DateFormat;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.NumberPicker;

public class DateTimePicker extends FrameLayout {

    private static final boolean DEFAULT_ENABLE_STATE = true;
    //声明变量常量
    private static final int HOURS_IN_HALF_DAY = 12;
    private static final int HOURS_IN_ALL_DAY = 24;
    private static final int DAYS_IN_ALL_WEEK = 7;
    private static final int DATE_SPINNER_MIN_VAL = 0;
    private static final int DATE_SPINNER_MAX_VAL = DAYS_IN_ALL_WEEK - 1;
    private static final int HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW = 0;
    private static final int HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW = 23;
    private static final int HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW = 1;
    private static final int HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW = 12;
    private static final int MINUT_SPINNER_MIN_VAL = 0;
    private static final int MINUT_SPINNER_MAX_VAL = 59;
    private static final int AMPM_SPINNER_MIN_VAL = 0;
    private static final int AMPM_SPINNER_MAX_VAL = 1;

    private final NumberPicker mDateSpinner;
    private final NumberPicker mHourSpinner;
    private final NumberPicker mMinuteSpinner;
    private final NumberPicker mAmPmSpinner;
    private Calendar mDate;

    private String[] mDateDisplayValues = new String[DAYS_IN_ALL_WEEK];

    private boolean mIsAm;

    private boolean mIs24HourView;

    private boolean mIsEnabled = DEFAULT_ENABLE_STATE;

    private boolean mInitialising;

    private OnDateTimeChangedListener mOnDateTimeChangedListener;

private NumberPicker.OnValueChangeListener mOnDateChangedListener = new NumberPicker.OnValueChangeListener() {    // 创建一个NumberPicker.OnValueChangeListener的匿名内部类，用于监听NumberPicker的值改变
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            mDate.add(Calendar.DAY_OF_YEAR, newVal - oldVal);    // 计算新旧值之间的差值，并将其加到mDate中
            updateDateControl();    // 更新日期控件
            onDateTimeChanged();    // 更新时间控件
        }
    };

    private NumberPicker.OnValueChangeListener mOnHourChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            boolean isDateChanged = false;
            Calendar cal = Calendar.getInstance();
            if (!mIs24HourView) {    // 判断是否是24小时制
                if (!mIsAm && oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY) {
                if (mIsAm && oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY) {    // 如果当前是上午，且当前小时是half day，则设置当前时间为下午
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, 1);
                    isDateChanged = true;
                } else if (mIsAm && oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {    // 如果当前是下午，且当前小时是half day，则设置当前时间为上午
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, -1);
                    isDateChanged = true;
                }
                
                if (oldVal == HOURS_IN_HALF_DAY - 1 && newVal == HOURS_IN_HALF_DAY ||    // 如果当前是上午，且当前小时是half day，则设置当前时间为下午
                        oldVal == HOURS_IN_HALF_DAY && newVal == HOURS_IN_HALF_DAY - 1) {
                    mIsAm = !mIsAm;
                    updateAmPmControl();
                }
            } else {
                if (oldVal == HOURS_IN_ALL_DAY - 1 && newVal == 0) {    // 如果当前是24小时制，且当前小时是all day，则设置当前时间为次日
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, 1);
                    isDateChanged = true;
                }
                else if (oldVal == 0 && newVal == HOURS_IN_ALL_DAY - 1) {    // 如果当前是24小时制，且当前小时是all day，则设置当前时间为次日
                    cal.setTimeInMillis(mDate.getTimeInMillis());
                    cal.add(Calendar.DAY_OF_YEAR, -1);
                    isDateChanged = true;
                }
            }
            int newHour = mHourSpinner.getValue() % HOURS_IN_HALF_DAY + (mIsAm ? 0 : HOURS_IN_HALF_DAY);    // 获取当前小时
            mDate.set(Calendar.HOUR_OF_DAY, newHour);    // 设置当前时间
            onDateTimeChanged();
            if (isDateChanged) {    // 如果日期改变，则更新当前日期
                setCurrentYear(cal.get(Calendar.YEAR));
                setCurrentMonth(cal.get(Calendar.MONTH));
                setCurrentDay(cal.get(Calendar.DAY_OF_MONTH));
            }
        }
    };

    private NumberPicker.OnValueChangeListener mOnMinuteChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            int minValue = mMinuteSpinner.getMinValue();    // 获取分钟数字选择器的最小值
            int maxValue = mMinuteSpinner.getMaxValue();    // 获取分钟数字选择器的最大值
            int offset = 0;
        
            if (oldVal == maxValue && newVal == minValue) {    // 如果旧的值是最大值，新的值是最小值，则偏移量加1
                offset += 1;
            } else if (oldVal == minValue && newVal == maxValue) {      // 如果旧的值是最小值，新的值是最大值，则偏移量减1
                offset -= 1;
            }
        
            if (offset != 0) {    // 如果偏移量不等于0，则添加偏移量
                mDate.add(Calendar.HOUR_OF_DAY, offset);    // 添加偏移量
                mHourSpinner.setValue(getCurrentHour());    // 设置小时数字选择器的值
                updateDateControl();    // 更新日期控件
                int newHour = getCurrentHourOfDay();    // 获取当前的小时
                if (newHour >= HOURS_IN_HALF_DAY) {    // 如果当前的小时大于等于12，则设置AM为false
                    mIsAm = false;
                    updateAmPmControl();    // 更新AM/PM控件
                } else {    // 否则，设置AM为true
                    mIsAm = true;   
                    updateAmPmControl();    // 更新AM/PM控件
                }
            }
            mDate.set(Calendar.MINUTE, newVal);    // 设置分钟数字选择器的值
            onDateTimeChanged();    // 更新日期控件
        }
    };

    private NumberPicker.OnValueChangeListener mOnAmPmChangedListener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            mIsAm = !mIsAm;    // 判断当前是上午还是下午
            if (mIsAm) {    // 根据当前是上午还是下午，调整时间
                mDate.add(Calendar.HOUR_OF_DAY, -HOURS_IN_HALF_DAY);
            } else {
                mDate.add(Calendar.HOUR_OF_DAY, HOURS_IN_HALF_DAY);
            }
        
            updateAmPmControl();    // 更新AM/PM控制
            onDateTimeChanged();    // 更新时间
        }
    };


    public interface OnDateTimeChangedListener {    
    
        void onDateTimeChanged(DateTimePicker view, int year, int month,    // 当时间改变时调用
                int dayOfMonth, int hourOfDay, int minute);
    }


    public DateTimePicker(Context context) {   // 构造函数，传入上下文和当前时间戳
        this(context, System.currentTimeMillis());
    }


    public DateTimePicker(Context context, long date) {    // 创建一个DateTimePicker对象，参数为context和date，dateFormat默认为24小时制
        this(context, date, DateFormat.is24HourFormat(context));
    }


    public DateTimePicker(Context context, long date, boolean is24HourView) {    // 创建DateTimePicker对象，传入上下文、日期和是否24小时视图
        super(context);
        mDate = Calendar.getInstance();
        mInitialising = true;
        mIsAm = getCurrentHourOfDay() >= HOURS_IN_HALF_DAY;
        inflate(context, R.layout.datetime_picker, this);

    
        mDateSpinner = (NumberPicker) findViewById(R.id.date);    //获取日期选择器
        mDateSpinner.setMinValue(DATE_SPINNER_MIN_VAL);    //设置最小值
        mDateSpinner.setMaxValue(DATE_SPINNER_MAX_VAL);    //设置最大值
        mDateSpinner.setOnValueChangedListener(mOnDateChangedListener);    //设置日期改变监听器

        
       mHourSpinner = (NumberPicker) findViewById(R.id.hour);
        mHourSpinner.setOnValueChangedListener(mOnHourChangedListener);
        mMinuteSpinner =  (NumberPicker) findViewById(R.id.minute);
        mMinuteSpinner.setMinValue(MINUT_SPINNER_MIN_VAL);
        mMinuteSpinner.setMaxValue(MINUT_SPINNER_MAX_VAL);
        mMinuteSpinner.setOnLongPressUpdateInterval(100);
        mMinuteSpinner.setOnValueChangedListener(mOnMinuteChangedListener);

    
        String[] stringsForAmPm = new DateFormatSymbols().getAmPmStrings();    // 设置AM/PM选择器
        mAmPmSpinner = (NumberPicker) findViewById(R.id.amPm);
        mAmPmSpinner.setMinValue(AMPM_SPINNER_MIN_VAL);
        mAmPmSpinner.setMaxValue(AMPM_SPINNER_MAX_VAL);
        mAmPmSpinner.setDisplayedValues(stringsForAmPm);
        mAmPmSpinner.setOnValueChangedListener(mOnAmPmChangedListener);

    
        updateDateControl();    // 更新日期控制
        updateHourControl();    // 更新小时控制
        updateAmPmControl();    // 更新AM/PM控制

        set24HourView(is24HourView);    // 设置24小时视图
        setCurrentDate(date);    // 设置当前日期
        setEnabled(isEnabled());    // 设置是否可用

        mInitialising = false;
    }

    @Override
    public void setEnabled(boolean enabled) {
    
        if (mIsEnabled == enabled) {    // 判断当前状态是否和传入的参数一致
            return;
        }
    
        super.setEnabled(enabled);    // 调用父类的setEnabled方法
        mDateSpinner.setEnabled(enabled);    // 设置日期选择器是否可用
        mMinuteSpinner.setEnabled(enabled);    // 设置分钟选择器是否可用
        mHourSpinner.setEnabled(enabled);    // 设置小时选择器是否可用
        mAmPmSpinner.setEnabled(enabled);    // 设置上午/下午选择器是否可用
        mIsEnabled = enabled;    // 更新状态
    }

   @Override
    public boolean isEnabled() {
        return mIsEnabled;
    }

    /**
     * Get the current date in millis
     *
     * @return the current date in millis
     */

public long getCurrentDateInTimeMillis() {    //获取当前日期的时间戳
        return mDate.getTimeInMillis();
    }
    /**
     * Set the current date
     *
     * @param date The current date in millis
     */

public void setCurrentDate(long date) {    //设置当前日期
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(date);
        setCurrentDate(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH),
                cal.get(Calendar.HOUR_OF_DAY), cal.get(Calendar.MINUTE));
    }

    /**
     * Set the current date
     *
     * @param year The current year
     * @param month The current month
     * @param dayOfMonth The current dayOfMonth
     * @param hourOfDay The current hourOfDay
     * @param minute The current minute
     */

public void setCurrentDate(int year, int month,
            int dayOfMonth, int hourOfDay, int minute) {    //设置当前日期
        setCurrentYear(year);        //设置当前年份
        setCurrentMonth(month);        //设置当前月份
        setCurrentDay(dayOfMonth);        //设置当前日期
        setCurrentHour(hourOfDay);        //设置当前小时
        setCurrentMinute(minute);        //设置当前分钟
    }

    /**
     * Get current year
     *
     * @return The current year
     */

public int getCurrentYear() {    //获取当前年份
        return mDate.get(Calendar.YEAR);
    }

    /**
     * Set current year
     *
     * @param year The current year
     */

public void setCurrentYear(int year) {    //设置当前年份
        if (!mInitialising && year == getCurrentYear()) {        //如果初始化完成且当前年份和传入年份相同，则直接返回
            return;
        }

        mDate.set(Calendar.YEAR, year);        //设置当前年份
        updateDateControl();        //更新日期控件
        onDateTimeChanged();        //日期改变时调用
    }

    /**
     * Get current month in the year
     *
     * @return The current month in the year
     */

public int getCurrentMonth() {    //获取当前月份
        return mDate.get(Calendar.MONTH);
    }

    /**
     * Set current month in the year
     *
     * @param month The month in the year
     */

public void setCurrentMonth(int month) {    //设置当前月份
        if (!mInitialising && month == getCurrentMonth()) {
            return;
        }
        mDate.set(Calendar.MONTH, month);
        updateDateControl();
        onDateTimeChanged();
    }

    /**
     * Get current day of the month
     *
     * @return The day of the month
     */

public int getCurrentDay() {    //获取当前日期
        return mDate.get(Calendar.DAY_OF_MONTH);
    }

    /**
     * Set current day of the month
     *
     * @param dayOfMonth The day of the month
     */

public void setCurrentDay(int dayOfMonth) {    //设置当前日期
        if (!mInitialising && dayOfMonth == getCurrentDay()) {
            return;
        }
        mDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
        updateDateControl();
        onDateTimeChanged();
    }

    /**
     * Get current hour in 24 hour mode, in the range (0~23)
     * @return The current hour in 24 hour mode
     */

public int getCurrentHourOfDay() {    //获取当前小时
        return mDate.get(Calendar.HOUR_OF_DAY);
    }

    private int getCurrentHour() {
        if (mIs24HourView){        // 24小时模式
            return getCurrentHourOfDay();
        } else {    // 12小时模式
            int hour = getCurrentHourOfDay();
            if (hour > HOURS_IN_HALF_DAY) {    // 当前小时大于12小时，返回当前小时减去12小时
                return hour - HOURS_IN_HALF_DAY;
            } else {        // 当前小时小于等于12小时，返回当前小时
                return hour == 0 ? HOURS_IN_HALF_DAY : hour;
            }
        }
    }

    /**
     * Set current hour in 24 hour mode, in the range (0~23)
     *
     * @param hourOfDay
     */

public void setCurrentHour(int hourOfDay) {    //设置当前小时

        if (!mInitialising && hourOfDay == getCurrentHourOfDay()) {        //如果初始化完成且当前小时和传入的参数相等，则直接返回
            return;
        }

        mDate.set(Calendar.HOUR_OF_DAY, hourOfDay);        //设置当前小时
        if (!mIs24HourView) {        //如果不是24小时制
            if (hourOfDay >= HOURS_IN_HALF_DAY) {            //如果传入的参数大于等于12
                mIsAm = false;        //设置AM为false
                if (hourOfDay > HOURS_IN_HALF_DAY) {        //如果传入的参数大于12
                    hourOfDay -= HOURS_IN_HALF_DAY;        //减去12
                }
            } else {
                mIsAm = true;    //设置AM为true
                if (hourOfDay == 0) {    //如果传入的参数等于0
                    hourOfDay = HOURS_IN_HALF_DAY;    //设置为12
                }
            }
            updateAmPmControl();    //更新AM/PM控制
        }
        mHourSpinner.setValue(hourOfDay);    //设置小时值
        onDateTimeChanged();    //日期改变时调用
    }

    /**
     * Get currentMinute
     *
     * @return The Current Minute
     */

public int getCurrentMinute() {    //获取当前分钟
        return mDate.get(Calendar.MINUTE);
    }

    /**
     * Set current minute
     */

public void setCurrentMinute(int minute) {    //设置当前分钟
        if (!mInitialising && minute == getCurrentMinute()) {        //如果初始化未完成，且分钟数相同，则返回
            return;
        }
        mMinuteSpinner.setValue(minute);        //设置分钟数
        mDate.set(Calendar.MINUTE, minute);        //设置日期
        onDateTimeChanged();        //更新时间
    }

    /**
     * @return true if this is in 24 hour view else false.
     */

public boolean is24HourView () {    //获取是否是24小时视图
        return mIs24HourView;
    }

    /**
     * Set whether in 24 hour or AM/PM mode.
     *
     * @param is24HourView True for 24 hour mode. False for AM/PM mode.
     */

public void set24HourView(boolean is24HourView) {    //设置24小时视图
        if (mIs24HourView == is24HourView) {
            return;
        }
        mIs24HourView = is24HourView;

        mAmPmSpinner.setVisibility(is24HourView ? View.GONE : View.VISIBLE);        //设置时间控制条的可见性
        int hour = getCurrentHourOfDay();        //获取当前的小时
        updateHourControl();        //更新小时控制条
        setCurrentHour(hour);        //设置当前的小时
        updateAmPmControl();        //更新上午/下午控制条
    }

    private void updateDateControl() {
        Calendar cal = Calendar.getInstance();        // 获取当前时间
        cal.setTimeInMillis(mDate.getTimeInMillis());
        cal.add(Calendar.DAY_OF_YEAR, -DAYS_IN_ALL_WEEK / 2 - 1);        // 设置当前时间所在的星期
        mDateSpinner.setDisplayedValues(null);        // 设置显示的值
        for (int i = 0; i < DAYS_IN_ALL_WEEK; ++i) {        // 遍历所有的星期
            cal.add(Calendar.DAY_OF_YEAR, 1);
            mDateDisplayValues[i] = (String) DateFormat.format("MM.dd EEEE", cal);
        }
        mDateSpinner.setDisplayedValues(mDateDisplayValues);        // 设置显示的值
        mDateSpinner.setValue(DAYS_IN_ALL_WEEK / 2);        // 设置当前时间所在的星期
        mDateSpinner.invalidate();
    }

    private void updateAmPmControl() {
        if (mIs24HourView) {        // 如果24小时视图是可见的，则隐藏AM/PM控制
            mAmPmSpinner.setVisibility(View.GONE);
        } else {
            int index = mIsAm ? Calendar.AM : Calendar.PM;     // 否则，如果当前是AM，则设置索引为Calendar.AM，否则设置为Calendar.PM
            mAmPmSpinner.setValue(index);
            mAmPmSpinner.setVisibility(View.VISIBLE);
        }
    }
    private void updateHourControl() {
        if (mIs24HourView) {    // 根据mIs24HourView的值来更新mHourSpinner的值
            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_24_HOUR_VIEW);
            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_24_HOUR_VIEW);
        } else {
            mHourSpinner.setMinValue(HOUR_SPINNER_MIN_VAL_12_HOUR_VIEW);
            mHourSpinner.setMaxValue(HOUR_SPINNER_MAX_VAL_12_HOUR_VIEW);
        }
    }

    /**
     * Set the callback that indicates the 'Set' button has been pressed.
     * @param callback the callback, if null will do nothing
     */

public void setOnDateTimeChangedListener(OnDateTimeChangedListener callback) {    //设置日期时间改变监听器
        mOnDateTimeChangedListener = callback;
    }

    private void onDateTimeChanged() {
        if (mOnDateTimeChangedListener != null) {        // 当日期时间改变时调用
            mOnDateTimeChangedListener.onDateTimeChanged(this, getCurrentYear(),
                    getCurrentMonth(), getCurrentDay(), getCurrentHourOfDay(), getCurrentMinute());
        }
    }
}