fix：nav高度获取边界问题修改

app/src/main/java/io/legado/app/ui/book/read/ReadBookMenuBar.kt

@@ -6,10 +6,8 @@ import androidx.compose.animation.AnimatedContent
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.SizeTransform
 import androidx.compose.animation.animateContentSize
-import androidx.compose.animation.core.LinearOutSlowInEasing
 import androidx.compose.animation.core.animateDpAsState
 import androidx.compose.animation.core.animateFloatAsState
-import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.animation.slideInHorizontally
@@ -73,6 +71,7 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.SideEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableIntStateOf
@@ -413,11 +412,13 @@ private fun ReadBookMenuSurface(
     }
     val isFloating = state.menuConfig.readMenuFloatingBottomBar
     val currentNavBarHeight = with(density) { WindowInsets.navigationBars.getBottom(this).toDp() }
-    var maxNavBarHeightValue by rememberSaveable { mutableFloatStateOf(0f) }
-    if (currentNavBarHeight.value > maxNavBarHeightValue) {
-        maxNavBarHeightValue = currentNavBarHeight.value
+    var lastValidNavBarHeightValue by rememberSaveable { mutableFloatStateOf(currentNavBarHeight.value) }
+    SideEffect {
+        if (currentNavBarHeight.value > 0f) {
+            lastValidNavBarHeightValue = currentNavBarHeight.value
+        }
     }
-    val navBarHeight = if (currentNavBarHeight.value > 0f) currentNavBarHeight else maxNavBarHeightValue.dp
+    val navBarHeight = if (currentNavBarHeight.value > 0f) currentNavBarHeight else lastValidNavBarHeightValue.dp
     val floatingHorizontalMargin = if (isFloating) 16.dp else 0.dp
     val floatingBottomMargin = if (isFloating) 16.dp + navBarHeight else 0.dp
     val mainHorizontalMargin =