pref: 加载更多防抖

app/src/main/java/com/huanchengfly/tieba/post/ui/widgets/compose/LoadMore.kt

@@ -2,15 +2,30 @@ package com.huanchengfly.tieba.post.ui.widgets.compose
 
 import androidx.compose.animation.animateContentSize
 import androidx.compose.foundation.gestures.Orientation
-import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.IntrinsicSize
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.material.*
+import androidx.compose.material.CircularProgressIndicator
+import androidx.compose.material.ExperimentalMaterialApi
+import androidx.compose.material.FractionalThreshold
+import androidx.compose.material.Surface
+import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
@@ -27,12 +42,17 @@ import androidx.compose.ui.unit.dp
 import com.huanchengfly.tieba.post.R
 import com.huanchengfly.tieba.post.ui.common.theme.compose.ExtendedTheme
 import com.huanchengfly.tieba.post.ui.common.theme.compose.loadMoreIndicator
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.sample
+import kotlinx.coroutines.launch
 import kotlin.math.abs
 import kotlin.math.roundToInt
 
 private val LoadDistance = 70.dp
 
-@OptIn(ExperimentalMaterialApi::class)
+@OptIn(ExperimentalMaterialApi::class, FlowPreview::class)
 @Composable
 fun LoadMoreLayout(
     isLoading: Boolean,
@@ -50,17 +70,42 @@ fun LoadMoreLayout(
 ) {
     val loadDistance = with(LocalDensity.current) { LoadDistance.toPx() }
 
+    val curOnLoadMore by rememberUpdatedState(newValue = onLoadMore)
+    var lastTriggerTime by remember { mutableStateOf(0L) }
+    var waitingStateReset by remember { mutableStateOf(false) }
+    val loadMoreFlow = remember {
+        MutableSharedFlow<Long>(
+            extraBufferCapacity = 1,
+            onBufferOverflow = BufferOverflow.DROP_LATEST
+        )
+    }
+    val coroutineScope = rememberCoroutineScope()
+    DisposableEffect(Unit) {
+        val job = coroutineScope.launch {
+            loadMoreFlow
+                .sample(500)
+                .collect {
+                    curOnLoadMore()
+                    waitingStateReset = true
+                    lastTriggerTime = it
+                }
+        }
+
+        onDispose { job.cancel() }
+    }
+
     val canLoadMore = remember(enableLoadMore, loadEnd) { enableLoadMore && !loadEnd }
     val curIsLoading by rememberUpdatedState(newValue = isLoading)
     val curCanLoadMore by rememberUpdatedState(newValue = canLoadMore)
 
-    var waitingStateReset by remember { mutableStateOf(false) }
 
     val swipeableState = rememberSwipeableState(false) { newValue ->
         if (newValue && !curIsLoading && curCanLoadMore) {
-            onLoadMore()
+            val curTime = System.currentTimeMillis()
-            waitingStateReset = true
+            coroutineScope.launch {
-            true
+                loadMoreFlow.emit(curTime)
+            }
+            curTime - lastTriggerTime >= 500
         } else !newValue
     }
 
@@ -71,6 +116,8 @@ fun LoadMoreLayout(
         }
     }
 
+    LaunchedEffect(isLoading) { swipeableState.animateTo(isLoading) }
+
     Box(
         modifier = Modifier
             .nestedScroll(swipeableState.LoadPreUpPostDownNestedScrollConnection)
@@ -96,8 +143,6 @@ fun LoadMoreLayout(
                 indicator(isLoading, loadEnd, swipeableState.targetValue)
             }
         }
-
-        LaunchedEffect(isLoading) { swipeableState.animateTo(isLoading) }
     }
 }