解决夏令时getDayOffset有误差bug

Author: jaaksi

app/src/main/java/org/jaaksi/pickerview/demo/ui/MixedTimeFormatFragment.kt

@@ -52,7 +52,7 @@ class MixedTimeFormatFragment : BaseFragment<FragmentMixedtimeFormatBinding>(),
                 ): CharSequence {
                     if (type == TimePicker.TYPE_MIXED_DATE) {
                         val text: CharSequence
-                        val dayOffset = DateUtil.getDayOffset(value, System.currentTimeMillis())
+                        val dayOffset = DateUtil.getIntervalDay(System.currentTimeMillis(),value)
                         text = when (dayOffset) {
                             0 -> "今天"
 

pickerview/src/main/java/org/jaaksi/pickerview/picker/TimePicker.kt

@@ -4,9 +4,9 @@ import android.content.Context
 import org.jaaksi.pickerview.adapter.ArrayWheelAdapter
 import org.jaaksi.pickerview.adapter.NumericWheelAdapter
 import org.jaaksi.pickerview.dialog.IPickerDialog
+import org.jaaksi.pickerview.util.DateUtil
 import org.jaaksi.pickerview.util.DateUtil.createDateFormat
 import org.jaaksi.pickerview.util.DateUtil.getDayOfMonth
-import org.jaaksi.pickerview.util.DateUtil.getDayOffset
 import org.jaaksi.pickerview.widget.BasePickerView
 import org.jaaksi.pickerview.widget.BasePickerView.OnSelectedListener
 import org.jaaksi.pickerview.widget.PickerView
@@ -492,9 +492,9 @@ class TimePicker private constructor(
     private fun isSameDay(isStart: Boolean): Boolean {
         return if (hasType(TYPE_MIXED_DATE)) {
             if (isStart) {
-                getDayOffset(selectedDate.time, mStartDate.timeInMillis) == 0
+                DateUtil.isSameDay(mStartDate.timeInMillis,selectedDate.time)
             } else {
-                getDayOffset(selectedDate.time, mEndDate.timeInMillis) == 0
+                DateUtil.isSameDay(mEndDate.timeInMillis, selectedDate.time)
             }
         } else {
             val year =
@@ -516,8 +516,8 @@ class TimePicker private constructor(
             val isSameStartDay: Boolean
             val isSameEndDay: Boolean
             if (hasType(TYPE_MIXED_DATE)) {
-                isSameStartDay = getDayOffset(selectedDate.time, mStartDate.timeInMillis) == 0
-                isSameEndDay = getDayOffset(selectedDate.time, mEndDate.timeInMillis) == 0
+                isSameStartDay = DateUtil.isSameDay(selectedDate.time, mStartDate.timeInMillis)
+                isSameEndDay = DateUtil.isSameDay(selectedDate.time, mEndDate.timeInMillis)
             } else {
                 val year =
                     if (hasType(TYPE_YEAR)) mYearPicker!!.selectedItem!! else mSelectedDate!![Calendar.YEAR]
@@ -622,7 +622,7 @@ class TimePicker private constructor(
      * 获取指定日期距离第0个的offset
      */
     private fun offsetStart(calendar: Calendar): Int {
-        return getDayOffset(calendar.timeInMillis, mStartDate.timeInMillis)
+        return DateUtil.getIntervalDay(mStartDate.timeInMillis, calendar.timeInMillis)
     }
 
     private val selectedDate: Date

pickerview/src/main/java/org/jaaksi/pickerview/util/DateUtil.kt

@@ -3,14 +3,15 @@ package org.jaaksi.pickerview.util
 import java.text.SimpleDateFormat
 import java.util.Calendar
 import java.util.Locale
+import kotlin.math.max
+import kotlin.math.min
 
 /**
  * 创建时间：2018年02月02日12:00 <br></br>
  * 作者：fuchaoyang <br></br>
  * 描述：时间工具类
  */
 object DateUtil {
-    const val ONE_DAY = 1000 * 60 * 60 * 24L
 
     @JvmStatic
     fun createDateFormat(format: String): SimpleDateFormat {
@@ -27,22 +28,46 @@ object DateUtil {
         return c[Calendar.DAY_OF_MONTH]
     }
 
+    // 判断两个时间戳是否是同一天
+    fun isSameDay(time1: Long, time2: Long): Boolean{
+        return time1.dayStart() == time2.dayStart()
+    }
+
     /**
-     * 获取两个时间相差的天数
-     *
-     * @param time1 time1
-     * @param time2 time2
-     * @return time1 - time2相差的天数
+     * 不能用时间戳差值 / 86400000, 夏令时会有误差
+     * @return endTime - startTime 相差的天数
      */
-    @JvmStatic
-    fun getDayOffset(time1: Long, time2: Long): Int {
-        // 将小的时间置为当天的0点
-        val offsetTime: Long = if (time1 > time2) {
-            time1 - time2.dayStart()
-        } else {
-            time1.dayStart() - time2
+    fun getIntervalDay(time1: Long, time2: Long): Int {
+        val cal1 = Calendar.getInstance().apply { timeInMillis = min(time1,time2) }
+        val cal2 = Calendar.getInstance().apply { timeInMillis = max(time1, time2) }
+
+        // 如果是同一年，直接计算 dayOfYear 差值
+        if (cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR)) {
+            return if (time1 > time2)
+                -(cal2.get(Calendar.DAY_OF_YEAR) - cal1.get(Calendar.DAY_OF_YEAR))
+            else
+                cal2.get(Calendar.DAY_OF_YEAR) - cal1.get(Calendar.DAY_OF_YEAR)
+        }
+
+        // 跨年计算
+        var daysBetween = 0
+
+        // 1. 计算起始年剩余的天数
+        val daysLeftInYear1 = cal1.getActualMaximum(Calendar.DAY_OF_YEAR) - cal1.get(Calendar.DAY_OF_YEAR)
+        daysBetween += daysLeftInYear1
+
+        // 2. 计算中间完整年份的天数
+        var year = cal1.get(Calendar.YEAR) + 1
+        while (year < cal2.get(Calendar.YEAR)) {
+            val tempCal = Calendar.getInstance().apply { set(Calendar.YEAR, year) }
+            daysBetween += tempCal.getActualMaximum(Calendar.DAY_OF_YEAR)
+            year++
         }
-        return (offsetTime / ONE_DAY).toInt()
+
+        // 3. 计算结束年已过的天数
+        daysBetween += cal2.get(Calendar.DAY_OF_YEAR)
+
+        return if (time1 > time2) -daysBetween else daysBetween
     }
 
     fun Long.toCalendar(): Calendar {