Merge pull request #5 from xunrua/main

预测性返回

androidApp/src/main/res/drawable/ic_launcher_background.xml

@@ -1,170 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-    android:width="108dp"
-    android:height="108dp"
-    android:viewportWidth="108"
-    android:viewportHeight="108">
-    <path
-        android:fillColor="#3DDC84"
-        android:pathData="M0,0h108v108h-108z" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M9,0L9,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,0L19,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M29,0L29,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M39,0L39,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M49,0L49,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M59,0L59,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M69,0L69,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M79,0L79,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M89,0L89,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M99,0L99,108"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,9L108,9"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,19L108,19"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,29L108,29"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,39L108,39"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,49L108,49"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,59L108,59"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,69L108,69"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,79L108,79"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,89L108,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M0,99L108,99"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,29L89,29"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,39L89,39"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,49L89,49"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,59L89,59"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,69L89,69"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M19,79L89,79"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M29,19L29,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M39,19L39,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M49,19L49,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M59,19L59,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M69,19L69,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-    <path
-        android:fillColor="#00000000"
-        android:pathData="M79,19L79,89"
-        android:strokeWidth="0.8"
-        android:strokeColor="#33FFFFFF" />
-</vector>

androidApp/src/main/res/drawable/ic_launcher_foreground.xml

@@ -1,30 +0,0 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:aapt="http://schemas.android.com/aapt"
-    android:width="108dp"
-    android:height="108dp"
-    android:viewportWidth="108"
-    android:viewportHeight="108">
-    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
-        <aapt:attr name="android:fillColor">
-            <gradient
-                android:endX="85.84757"
-                android:endY="92.4963"
-                android:startX="42.9492"
-                android:startY="49.59793"
-                android:type="linear">
-                <item
-                    android:color="#44000000"
-                    android:offset="0.0" />
-                <item
-                    android:color="#00000000"
-                    android:offset="1.0" />
-            </gradient>
-        </aapt:attr>
-    </path>
-    <path
-        android:fillColor="#FFFFFF"
-        android:fillType="nonZero"
-        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
-        android:strokeWidth="1"
-        android:strokeColor="#00000000" />
-</vector>

androidApp/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@drawable/ic_launcher_background" />
-    <foreground android:drawable="@drawable/ic_launcher_foreground" />
-</adaptive-icon>

androidApp/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -1,5 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
-    <background android:drawable="@drawable/ic_launcher_background" />
-    <foreground android:drawable="@drawable/ic_launcher_foreground" />
-</adaptive-icon>

shared/src/androidMain/kotlin/plus/rua/project/Platform.android.kt

@@ -1,9 +1,12 @@
 package plus.rua.project
 
 import android.os.Build
+import androidx.activity.BackEventCompat
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.PredictiveBackHandler
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.rememberCoroutineScope
 import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.flow.Flow
 
 class AndroidPlatform : Platform {
     override val name: String = "Android ${Build.VERSION.SDK_INT}"
@@ -22,19 +25,20 @@ actual fun PredictiveBackHandler(
     onBack: () -> Unit,
     onCancel: () -> Unit
 ) {
-    if (Build.VERSION.SDK_INT >= 34) {
-        rememberCoroutineScope()
-        androidx.activity.compose.PredictiveBackHandler(enabled) { progress ->
-            try {
-                progress.collect { backEvent ->
-                    onProgress(backEvent.progress)
-                }
-                onBack()
-            } catch (e: CancellationException) {
-                onCancel()
+    // 官方 PredictiveBackHandler — Flow 模式：collect 完成=返回，CancellationException=取消
+    PredictiveBackHandler(enabled = enabled) { progress: Flow<BackEventCompat> ->
+        try {
+            progress.collect { event ->
+                onProgress(event.progress)
             }
+            onBack()
+        } catch (e: CancellationException) {
+            onCancel()
         }
-    } else {
-        androidx.activity.compose.BackHandler(enabled = enabled, onBack = onBack)
+    }
+
+    // 降级：部分设备（如 OPPO/ColorOS）不通过 OnBackInvokedCallback 分发返回事件
+    BackHandler(enabled = enabled) {
+        onBack()
     }
 }

shared/src/commonMain/kotlin/plus/rua/project/App.kt

@@ -1,117 +1,203 @@
 package plus.rua.project
 
-import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.Spring
+import androidx.compose.animation.core.spring
 import androidx.compose.animation.core.tween
-import androidx.compose.animation.fadeIn
-import androidx.compose.animation.fadeOut
-import androidx.compose.animation.slideInHorizontally
-import androidx.compose.animation.slideOutHorizontally
-import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.darkColorScheme
 import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.GraphicsLayerScope
 import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.launch
 import plus.rua.project.ui.AboutScreen
 import plus.rua.project.ui.CalendarMonthView
 import plus.rua.project.ui.LicensesScreen
+import plus.rua.project.ui.lerp
 
 private enum class Screen { Main, About, Licenses }
 
+/** 返回手势动画：顶层页面滑出 + 淡出 + 缩小 + 圆角阴影 */
+private fun GraphicsLayerScope.applyDismissTransform(progress: Float) {
+    // 二次缓动：小幅手势产生更柔和的视觉变化，大幅手势仍达到完整效果
+    val p = progress * progress
+    translationX = p * size.width * 0.5f
+    scaleX = 1f - p * 0.08f
+    scaleY = 1f - p * 0.08f
+    alpha = 1f - p
+    shadowElevation = 32.dp.toPx() * p
+    shape = RoundedCornerShape(28.dp * p)
+    clip = p > 0.01f
+}
+
+/** 底层页面缩放：随返回进度从 baseScale 放大到 1.0 */
+private fun GraphicsLayerScope.applyRevealTransform(
+    progress: Float,
+    forwardProgress: Float,
+    isForwardAnimating: Boolean
+) {
+    val p = progress * progress
+    val baseScale = 0.92f + 0.08f * p
+    val scale = if (isForwardAnimating) lerp(1f, baseScale, forwardProgress) else baseScale
+    scaleX = scale
+    scaleY = scale
+}
+
+/** 前向导航动画：新页面从右侧滑入 */
+private fun GraphicsLayerScope.applyEnterTransform(progress: Float) {
+    translationX = (1f - progress) * size.width
+    alpha = progress
+}
+
 /**
  * 应用入口 Composable，根据系统主题切换明暗 ColorScheme 并管理页面导航。
+ *
+ * 使用 Box 分层布局替代 AnimatedContent，支持预测性返回手势：
+ * - 底层页面始终组合（状态保持），缩放显现
+ * - 顶层页面在手势期间平滑位移、缩放、圆角、阴影
+ * - 前向导航从右侧滑入，返回导航跟手驱动
  */
 @Composable
 @Preview(name = "Calendar App")
 fun App() {
     var currentScreen by remember { mutableStateOf(Screen.Main) }
     var backProgress by remember { mutableFloatStateOf(0f) }
+    val scope = rememberCoroutineScope()
 
-    val handleBack: () -> Unit = {
-        backProgress = 0f
-        when (currentScreen) {
-            Screen.About -> currentScreen = Screen.Main
-            Screen.Licenses -> currentScreen = Screen.About
-            else -> {}
+    val backAnimProgress = remember { Animatable(0f) }
+    val effectiveBackProgress by remember {
+        derivedStateOf { maxOf(backProgress, backAnimProgress.value) }
+    }
+
+    var forwardTarget by remember { mutableStateOf<Screen?>(null) }
+    val forwardProgress = remember { Animatable(1f) }
+
+    var isHandlingBack by remember { mutableStateOf(false) }
+    val handleBack: () -> Unit = lambda@{
+        if (isHandlingBack) return@lambda
+        isHandlingBack = true
+        scope.launch {
+            backAnimProgress.snapTo(backProgress)
+            backProgress = 0f
+            backAnimProgress.animateTo(1f, spring(stiffness = Spring.StiffnessMedium, dampingRatio = Spring.DampingRatioNoBouncy))
+            currentScreen = when (currentScreen) {
+                Screen.About -> Screen.Main
+                Screen.Licenses -> Screen.About
+                else -> currentScreen
+            }
+            backAnimProgress.animateTo(0f, spring(stiffness = Spring.StiffnessMedium, dampingRatio = Spring.DampingRatioNoBouncy))
+            isHandlingBack = false
         }
     }
 
     val handleCancel: () -> Unit = {
-        backProgress = 0f
+        scope.launch {
+            backAnimProgress.snapTo(backProgress)
+            backProgress = 0f
+            backAnimProgress.animateTo(0f, spring(stiffness = Spring.StiffnessMediumLow))
+        }
+    }
+
+    val navigateTo: (Screen) -> Unit = { target ->
+        if (forwardTarget == null) {
+            scope.launch {
+                forwardTarget = target
+                currentScreen = target
+                forwardProgress.snapTo(0f)
+                forwardProgress.animateTo(1f, tween(350, easing = FastOutSlowInEasing))
+                forwardTarget = null
+            }
+        }
     }
 
     val colorScheme = if (isSystemInDarkTheme()) darkColorScheme() else lightColorScheme()
     MaterialTheme(colorScheme = colorScheme) {
-        AnimatedContent(
-            targetState = currentScreen,
-            transitionSpec = {
-                if (targetState.ordinal > initialState.ordinal) {
-                    // 正向导航：新页面从右侧滑入覆盖，旧页面略微左移+淡出
-                    (slideInHorizontally { it } + fadeIn()) togetherWith
-                            (slideOutHorizontally { -it / 4 } + fadeOut())
-                } else {
-                    // 返回导航：新页面从左侧滑入，旧页面向右侧滑出
-                    (slideInHorizontally(animationSpec = tween(250)) { -it } + fadeIn(
-                        animationSpec = tween(
-                            250
+        Box(modifier = Modifier.fillMaxSize()) {
+            // Layer 0: CalendarMonthView（始终组合以保持状态）
+            CalendarMonthView(
+                modifier = Modifier.graphicsLayer {
+                    if (currentScreen != Screen.Main) {
+                        applyRevealTransform(
+                            effectiveBackProgress,
+                            forwardProgress.value,
+                            forwardTarget != null
                         )
-                    )) togetherWith
-                            (slideOutHorizontally(animationSpec = tween(250)) { it } + fadeOut(
-                                animationSpec = tween(250)
-                            ))
-                }
-            },
-            modifier = Modifier.fillMaxSize()
-        ) { screen ->
-            when (screen) {
-                Screen.Main -> CalendarMonthView(
-                    modifier = Modifier,
-                    onNavigateToAbout = { currentScreen = Screen.About }
+                    }
+                },
+                onNavigateToAbout = { navigateTo(Screen.About) }
+            )
+
+            // Layer 1: AboutScreen（About 或 Licenses 页面时组合）
+            if (currentScreen == Screen.About || currentScreen == Screen.Licenses) {
+                AboutScreen(
+                    onBack = {
+                        if (currentScreen == Screen.About) handleBack()
+                    },
+                    onNavigateToLicenses = {
+                        if (currentScreen == Screen.About) navigateTo(Screen.Licenses)
+                    },
+                    modifier = Modifier.graphicsLayer {
+                        when (currentScreen) {
+                            Screen.Licenses -> applyRevealTransform(
+                                effectiveBackProgress,
+                                forwardProgress.value,
+                                forwardTarget == Screen.Licenses
+                            )
+
+                            Screen.About -> {
+                                val bp = effectiveBackProgress
+                                val fp = forwardProgress.value
+                                when {
+                                    bp > 0.001f -> applyDismissTransform(bp)
+                                    fp < 0.999f && forwardTarget == Screen.About -> applyEnterTransform(fp)
+                                }
+                            }
+
+                            else -> {}
+                        }
+                    }
                 )
+            }
 
-                Screen.About -> {
-                    PredictiveBackHandler(
-                        enabled = backProgress == 0f,
-                        onProgress = { backProgress = it },
-                        onBack = handleBack,
-                        onCancel = handleCancel
-                    )
-                    AboutScreen(
-                        onBack = { currentScreen = Screen.Main },
-                        onNavigateToLicenses = { currentScreen = Screen.Licenses },
-                        modifier = Modifier.graphicsLayer {
-                            translationX = backProgress * size.width * 0.3f
-                            scaleX = 1f - backProgress * 0.05f
-                            scaleY = 1f - backProgress * 0.05f
+            // Layer 2: LicensesScreen（Licenses 页面时组合）
+            if (currentScreen == Screen.Licenses) {
+                LicensesScreen(
+                    onBack = handleBack,
+                    modifier = Modifier.graphicsLayer {
+                        val bp = effectiveBackProgress
+                        val fp = forwardProgress.value
+                        when {
+                            bp > 0.001f -> applyDismissTransform(bp)
+                            fp < 0.999f && forwardTarget == Screen.Licenses -> applyEnterTransform(fp)
                         }
-                    )
-                }
+                    }
+                )
+            }
 
-                Screen.Licenses -> {
-                    PredictiveBackHandler(
-                        enabled = backProgress == 0f,
-                        onProgress = { backProgress = it },
-                        onBack = handleBack,
-                        onCancel = handleCancel
-                    )
-                    LicensesScreen(
-                        onBack = { currentScreen = Screen.About },
-                        modifier = Modifier.graphicsLayer {
-                            translationX = backProgress * size.width * 0.3f
-                            scaleX = 1f - backProgress * 0.05f
-                            scaleY = 1f - backProgress * 0.05f
-                        }
-                    )
-                }
+            // 预测性返回手势
+            if (currentScreen != Screen.Main) {
+                PredictiveBackHandler(
+                    enabled = !backAnimProgress.isRunning && !isHandlingBack && forwardTarget == null,
+                    onProgress = { backProgress = it },
+                    onBack = handleBack,
+                    onCancel = handleCancel
+                )
             }
         }
     }