xfy
ddc852a667
Move shared constants and helper functions into CalendarUtils.kt, replace manual state synchronization with derivedStateOf in CalendarViewModel and UI composables. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
87 lines
2.6 KiB
Kotlin
87 lines
2.6 KiB
Kotlin
package plus.rua.project.ui
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import kotlinx.datetime.DatePeriod
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import kotlinx.datetime.LocalDate
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import kotlinx.datetime.minus
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import kotlinx.datetime.number
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import kotlinx.datetime.plus
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/** 无限分页中心页，用于 HorizontalPager 的起始位置 */
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const val START_PAGE = Int.MAX_VALUE / 2
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/** 折叠判定阈值：progress > 此值时折叠，< 此值时展开 */
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const val COLLAPSE_THRESHOLD = 0.5f
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/** 滑动偏移插值阈值：abs(offsetFraction) > 此值时启用插值 */
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const val OFFSET_FRACTION_THRESHOLD = 0.01f
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/** 行内 vertical padding (dp) */
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const val ROW_PADDING_DP = 4
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/** 日历网格水平 padding (dp) */
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const val HORIZONTAL_PADDING_DP = 16
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/** BottomCard 拖拽手势范围 (dp) */
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const val DRAG_RANGE_DP = 200
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/** 线性插值 */
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fun lerp(start: Float, end: Float, fraction: Float): Float = start + (end - start) * fraction
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/**
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* 计算月份在日历网格中需要的行数（4/5/6）。
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*/
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fun calculateWeeksCount(year: Int, month: Int): Int {
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val firstOfMonth = LocalDate(year, month, 1)
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val offset = firstOfMonth.dayOfWeek.ordinal
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val nextMonth = if (month == 12) LocalDate(year + 1, 1, 1) else LocalDate(year, month + 1, 1)
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val daysInMonth = nextMonth.minus(DatePeriod(days = 1)).day
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return ((offset + daysInMonth - 1) / 7) + 1
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}
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/**
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* 根据 pager 页码计算该页月份的行数。
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*/
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fun calculateWeeksCountForPage(page: Int, today: LocalDate): Int {
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val initialYear = today.year
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val initialMonth = today.month.number
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val offset = page - START_PAGE
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val totalMonths = initialYear * 12 + (initialMonth - 1) + offset
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val year = totalMonths / 12
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val month = totalMonths % 12 + 1
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return calculateWeeksCount(year, month)
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}
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/**
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* 页码转年月。
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*/
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fun pageToYearMonth(page: Int, initialYear: Int, initialMonth: Int): Pair<Int, Int> {
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val offset = page - START_PAGE
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val totalMonths = initialYear * 12 + (initialMonth - 1) + offset
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return Pair(totalMonths / 12, totalMonths % 12 + 1)
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}
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/**
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* 年月转页码。
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*/
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fun yearMonthToPage(year: Int, month: Int, initialYear: Int, initialMonth: Int): Int {
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val targetTotal = year * 12 + (month - 1)
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val initialTotal = initialYear * 12 + (initialMonth - 1)
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return START_PAGE + (targetTotal - initialTotal)
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}
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/**
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* 获取日期所在周的周一。
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*/
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fun LocalDate.toWeekMonday(): LocalDate {
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val dayOfWeekOrdinal = dayOfWeek.ordinal
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return minus(DatePeriod(days = dayOfWeekOrdinal))
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}
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/**
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* 根据 pager 页码计算该页对应的周周一日期。
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*/
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fun pageToWeekMonday(page: Int, initial: LocalDate): LocalDate {
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val offset = page - START_PAGE
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return initial.plus(DatePeriod(days = offset * 7))
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}
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