Animations and change page extensions

WojciechOsak · May 26, 2024 · 2e9ed8a · 2e9ed8a
1 parent 1a57b61
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diff --git a/calendar/src/commonMain/kotlin/io/wojciechosak/calendar/animation/CalendarAnimator.kt b/calendar/src/commonMain/kotlin/io/wojciechosak/calendar/animation/CalendarAnimator.kt
@@ -21,71 +21,83 @@ import kotlin.math.floor
  */
 @OptIn(ExperimentalFoundationApi::class)
 class CalendarAnimator(private val startDate: LocalDate) {
-    enum class AnimationMode {
-        MONTH,
-        DAY,
-        WEEK,
-    }
+	enum class AnimationMode {
+		MONTH,
+		DAY,
+		WEEK,
+	}
 
-    private var pagerState: PagerState? = null
+	private var pagerState: PagerState? = null
 
-    private var mode: AnimationMode = AnimationMode.MONTH
+	private var mode: AnimationMode = AnimationMode.MONTH
 
-    internal fun updatePagerState(pagerState: PagerState) {
-        this.pagerState = pagerState
-    }
+	internal fun updatePagerState(pagerState: PagerState) {
+		this.pagerState = pagerState
+	}
 
-    internal fun setAnimationMode(mode: AnimationMode) {
-        this.mode = mode
-    }
+	internal fun setAnimationMode(mode: AnimationMode) {
+		this.mode = mode
+	}
 
-    suspend fun animateTo(
-        target: LocalDate,
-        pageOffsetFraction: Float = 0f,
-        animationSpec: AnimationSpec<Float> = spring(stiffness = Spring.StiffnessMediumLow),
-    ) {
-        val initialPage = INITIAL_PAGE_INDEX
-        val currentDate =
-            when (mode) {
-                AnimationMode.MONTH ->
-                    startDate.plus(
-                        (pagerState?.targetPage ?: 0) - initialPage,
-                        DateTimeUnit.MONTH,
-                    )
+	suspend fun animateToNextPage() {
+		pagerState?.animateScrollToPage(pagerState!!.currentPage + 1)
+	}
 
-                AnimationMode.DAY ->
-                    startDate.plus(
-                        (pagerState?.targetPage ?: 0) - initialPage,
-                        DateTimeUnit.DAY,
-                    )
+	suspend fun animateToPreviousPage() {
+		pagerState?.animateScrollToPage(pagerState!!.currentPage - 1)
+	}
 
-                AnimationMode.WEEK ->
-                    startDate.plus(
-                        (pagerState?.targetPage ?: 0) - initialPage,
-                        DateTimeUnit.WEEK,
-                    )
-            }
-        val targetDate =
-            target.run {
-                if (mode == AnimationMode.MONTH) {
-                    copy(day = currentDate.dayOfMonth)
-                } else {
-                    this
-                }
-            }
-        val diff = currentDate.periodUntil(targetDate)
-        val offset =
-            when (mode) {
-                AnimationMode.MONTH -> diff.months + diff.years * 12
-                AnimationMode.DAY -> currentDate.daysUntil(targetDate)
-                AnimationMode.WEEK -> floor(currentDate.daysUntil(targetDate) / 7f).toInt()
-            }
-        if (initialPage + offset > 0) {
-            pagerState?.animateScrollToPage(
-                page = (pagerState?.settledPage ?: initialPage) + offset,
-                pageOffsetFraction = pageOffsetFraction,
-                animationSpec = animationSpec,
-            )
-        }
-    }
+	suspend fun scrollToPage(page: Int, pageOffsetFraction: Float = 0f) {
+		pagerState?.scrollToPage(page, pageOffsetFraction = pageOffsetFraction)
+	}
+
+	suspend fun animateTo(
+		target: LocalDate,
+		pageOffsetFraction: Float = 0f,
+		animationSpec: AnimationSpec<Float> = spring(stiffness = Spring.StiffnessMediumLow),
+	) {
+		val initialPage = INITIAL_PAGE_INDEX
+		val currentDate =
+			when (mode) {
+				AnimationMode.MONTH ->
+					startDate.plus(
+						(pagerState?.targetPage ?: 0) - initialPage,
+						DateTimeUnit.MONTH,
+					)
+
+				AnimationMode.DAY ->
+					startDate.plus(
+						(pagerState?.targetPage ?: 0) - initialPage,
+						DateTimeUnit.DAY,
+					)
+
+				AnimationMode.WEEK ->
+					startDate.plus(
+						(pagerState?.targetPage ?: 0) - initialPage,
+						DateTimeUnit.WEEK,
+					)
+			}
+		val targetDate =
+			target.run {
+				if (mode == AnimationMode.MONTH) {
+					copy(day = currentDate.dayOfMonth)
+				} else {
+					this
+				}
+			}
+		val diff = currentDate.periodUntil(targetDate)
+		val offset =
+			when (mode) {
+				AnimationMode.MONTH -> diff.months + diff.years * 12
+				AnimationMode.DAY -> currentDate.daysUntil(targetDate)
+				AnimationMode.WEEK -> floor(currentDate.daysUntil(targetDate) / 7f).toInt()
+			}
+		if (initialPage + offset > 0) {
+			pagerState?.animateScrollToPage(
+				page = (pagerState?.settledPage ?: initialPage) + offset,
+				pageOffsetFraction = pageOffsetFraction,
+				animationSpec = animationSpec,
+			)
+		}
+	}
 }
diff --git a/calendar/src/commonMain/kotlin/io/wojciechosak/calendar/config/CalendarConfig.kt b/calendar/src/commonMain/kotlin/io/wojciechosak/calendar/config/CalendarConfig.kt
@@ -8,6 +8,7 @@ import androidx.compose.runtime.remember
 import io.wojciechosak.calendar.utils.toMonthYear
 import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.minus
 import kotlinx.datetime.plus
 
 /**
@@ -25,15 +26,15 @@ import kotlinx.datetime.plus
  */
 @Stable
 data class CalendarConfig(
-    val minDate: LocalDate,
-    val maxDate: LocalDate,
-    val monthYear: MonthYear,
-    val dayOfWeekOffset: Int,
-    val showNextMonthDays: Boolean,
-    val showPreviousMonthDays: Boolean,
-    val showHeader: Boolean,
-    val showWeekdays: Boolean,
-    val selectedDates: List<LocalDate>,
+	val minDate: LocalDate,
+	val maxDate: LocalDate,
+	val monthYear: MonthYear,
+	val dayOfWeekOffset: Int,
+	val showNextMonthDays: Boolean,
+	val showPreviousMonthDays: Boolean,
+	val showHeader: Boolean,
+	val showWeekdays: Boolean,
+	val selectedDates: List<LocalDate>,
 )
 
 /**
@@ -53,28 +54,42 @@ data class CalendarConfig(
  */
 @Composable
 fun rememberCalendarState(
-    startDate: LocalDate,
-    minDate: LocalDate = LocalDate(1971, 1, 1),
-    maxDate: LocalDate = startDate.plus(15, DateTimeUnit.YEAR),
-    monthOffset: Int,
-    dayOfWeekOffset: Int = 0,
-    showNextMonthDays: Boolean = true,
-    showPreviousMonthDays: Boolean = true,
-    showHeader: Boolean = true,
-    showWeekdays: Boolean = true,
-    selectedDates: MutableList<LocalDate> = mutableListOf(),
+	startDate: LocalDate,
+	minDate: LocalDate = LocalDate(1971, 1, 1),
+	maxDate: LocalDate = startDate.plus(15, DateTimeUnit.YEAR),
+	monthOffset: Int,
+	dayOfWeekOffset: Int = 0,
+	showNextMonthDays: Boolean = true,
+	showPreviousMonthDays: Boolean = true,
+	showHeader: Boolean = true,
+	showWeekdays: Boolean = true,
+	selectedDates: MutableList<LocalDate> = mutableListOf(),
 ): MutableState<CalendarConfig> = remember {
-    mutableStateOf(
-        CalendarConfig(
-            minDate = minDate,
-            maxDate = maxDate,
-            monthYear = startDate.plus(monthOffset, DateTimeUnit.MONTH).toMonthYear(),
-            dayOfWeekOffset = dayOfWeekOffset,
-            showNextMonthDays = showNextMonthDays,
-            showPreviousMonthDays = showPreviousMonthDays,
-            showHeader = showHeader,
-            showWeekdays = showWeekdays,
-            selectedDates = selectedDates,
-        ),
-    )
+	mutableStateOf(
+		CalendarConfig(
+			minDate = minDate,
+			maxDate = maxDate,
+			monthYear = startDate.plus(monthOffset, DateTimeUnit.MONTH).toMonthYear(),
+			dayOfWeekOffset = dayOfWeekOffset,
+			showNextMonthDays = showNextMonthDays,
+			showPreviousMonthDays = showPreviousMonthDays,
+			showHeader = showHeader,
+			showWeekdays = showWeekdays,
+			selectedDates = selectedDates,
+		),
+	)
 }
+
+fun MutableState<CalendarConfig>.nextMonth() {
+	val currentConfig = value
+	value = value.copy(
+		monthYear = currentConfig.monthYear.toLocalDate().plus(1, DateTimeUnit.MONTH).toMonthYear()
+	)
+}
+
+fun MutableState<CalendarConfig>.previousMonth() {
+	val currentConfig = value
+	value = value.copy(
+		monthYear = currentConfig.monthYear.toLocalDate().minus(1, DateTimeUnit.MONTH).toMonthYear()
+	)
+}
diff --git a/docs.md b/docs.md
@@ -178,3 +178,10 @@ Button(onClick = {
 }
 ```
 
+CalendarAnimator provides also pager methods like:
+
+```kotlin
+animateToNextPage()
+animateToPreviousPage()
+scrollToPage(page: Int, pageOffsetFraction: Float = 0f)
+```