图片添加加载效果

- 为AsyncImage添加了Shimmer加载效果
- 优化了热门动态的加载逻辑
- 统一了ViewModel的重置方法名

app/src/main/java/com/aiosman/ravenow/ui/index/tabs/moment/tabs/hot/HotMomentViewModel.kt

@@ -2,51 +2,86 @@ package com.aiosman.ravenow.ui.index.tabs.moment.tabs.hot
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import androidx.paging.Pager
-import androidx.paging.PagingConfig
-import androidx.paging.PagingData
-import androidx.paging.cachedIn
-import com.aiosman.ravenow.AppState
 import com.aiosman.ravenow.data.MomentService
 import com.aiosman.ravenow.entity.MomentEntity
-import com.aiosman.ravenow.entity.MomentLoaderExtraArgs
-import com.aiosman.ravenow.entity.MomentPagingSource
-import com.aiosman.ravenow.entity.MomentRemoteDataSource
 import com.aiosman.ravenow.entity.MomentServiceImpl
-import com.aiosman.ravenow.ui.index.tabs.moment.BaseMomentModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
-import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
-import org.greenrobot.eventbus.EventBus
 
 
 object HotMomentViewModel : ViewModel() {
     private val momentService: MomentService = MomentServiceImpl()
-    private val _discoverMomentsFlow =
-        MutableStateFlow<PagingData<MomentEntity>>(PagingData.empty())
-    val discoverMomentsFlow = _discoverMomentsFlow.asStateFlow()
-    var firstLoad = true
-    fun refreshPager() {
-        if (!firstLoad) {
-            return
-        }
-        firstLoad = false
+    private val _discoverMoments = MutableStateFlow<List<MomentEntity>>(emptyList())
+    val discoverMoments = _discoverMoments.asStateFlow()
+    
+    private val _isLoading = MutableStateFlow(false)
+    val isLoading = _isLoading.asStateFlow()
+    
+    private val _isRefreshing = MutableStateFlow(false)
+    val isRefreshing = _isRefreshing.asStateFlow()
+    
+    private var currentPage = 1
+    private var hasMoreData = true
+    private val pageSize = 20
+    
+    fun loadMoments() {
+        if (_isLoading.value || !hasMoreData) return
+        
         viewModelScope.launch {
-            Pager(
-                config = PagingConfig(pageSize = 5, enablePlaceholders = false),
-                pagingSourceFactory = {
-                    MomentPagingSource(
-                        MomentRemoteDataSource(momentService),
-                        trend = true
-                    )
+            _isLoading.value = true
+            try {
+                val response = momentService.getMoments(
+                    pageNumber = currentPage,
+                    trend = true
+                )
+                
+                if (response.list.isNotEmpty()) {
+                    if (currentPage == 1) {
+                        _discoverMoments.value = response.list
+                    } else {
+                        _discoverMoments.value = _discoverMoments.value + response.list
+                    }
+                    currentPage++
+                    hasMoreData = response.list.size >= response.pageSize
+                } else {
+                    hasMoreData = false
                 }
-            ).flow.cachedIn(viewModelScope).collectLatest {
-                _discoverMomentsFlow.value = it
+            } catch (e: Exception) {
+                // 处理错误
+                e.printStackTrace()
+            } finally {
+                _isLoading.value = false
             }
         }
     }
-    fun ResetModel(){
-        firstLoad = true
+    
+    fun refreshMoments() {
+        viewModelScope.launch {
+            _isRefreshing.value = true
+            currentPage = 1
+            hasMoreData = true
+            try {
+                val response = momentService.getMoments(
+                    pageNumber = 1,
+                    trend = true
+                )
+                _discoverMoments.value = response.list
+                currentPage = 2
+                hasMoreData = response.list.size >= response.pageSize
+            } catch (e: Exception) {
+                e.printStackTrace()
+            } finally {
+                _isRefreshing.value = false
+            }
+        }
+    }
+    
+    fun resetModel() {
+        currentPage = 1
+        hasMoreData = true
+        _discoverMoments.value = emptyList()
+        _isLoading.value = false
+        _isRefreshing.value = false
     }
 }

app/src/main/java/com/aiosman/ravenow/ui/index/tabs/moment/tabs/hot/Moment.kt

@@ -15,6 +15,8 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.grid.rememberLazyGridState
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.ExperimentalMaterialApi
@@ -29,13 +31,15 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
+import androidx.compose.runtime.snapshotFlow
+import kotlinx.coroutines.flow.collectLatest
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.unit.dp
-import androidx.paging.compose.collectAsLazyPagingItems
+import androidx.compose.runtime.collectAsState
 import com.aiosman.ravenow.LocalAppTheme
 import com.aiosman.ravenow.LocalNavController
 import com.aiosman.ravenow.R
@@ -57,12 +61,14 @@ fun HotMomentsList() {
     val navController = LocalNavController.current
     val navigationBarPaddings =
         WindowInsets.navigationBars.asPaddingValues().calculateBottomPadding() + 48.dp
+    val isRefreshing by model.isRefreshing.collectAsState()
+    
     LaunchedEffect(Unit) {
-        model.refreshPager()
+        model.loadMoments()
     }
-    var refreshing by remember { mutableStateOf(false) }
-    val state = rememberPullRefreshState(refreshing, onRefresh = {
-        model.refreshPager()
+    
+    val state = rememberPullRefreshState(isRefreshing, onRefresh = {
+        model.refreshMoments()
     })
 
     Column(
@@ -84,7 +90,7 @@ fun HotMomentsList() {
                 .padding(2.dp)
         ) {
             DiscoverView()
-            PullRefreshIndicator(refreshing, state, Modifier.align(Alignment.TopCenter))
+            PullRefreshIndicator(isRefreshing, state, Modifier.align(Alignment.TopCenter))
         }
     }
 }
@@ -93,17 +99,37 @@ fun HotMomentsList() {
 @Composable
 fun DiscoverView() {
     val model = HotMomentViewModel
-    var dataFlow = model.discoverMomentsFlow
-    var moments = dataFlow.collectAsLazyPagingItems()
+    val moments by model.discoverMoments.collectAsState()
+    val isLoading by model.isLoading.collectAsState()
     val context = LocalContext.current
     val navController = LocalNavController.current
+    val gridState = rememberLazyGridState()
+    
+    // 监听滚动到底部，自动加载更多
+    LaunchedEffect(gridState, moments.size) {
+        snapshotFlow {
+            val layoutInfo = gridState.layoutInfo
+            val visibleItemsInfo = layoutInfo.visibleItemsInfo
+            if (visibleItemsInfo.isNotEmpty() && moments.isNotEmpty()) {
+                val lastVisibleItemIndex = visibleItemsInfo.lastOrNull()?.index ?: 0
+                lastVisibleItemIndex >= moments.size - 6 // 距离底部还有6个项目时开始加载
+            } else {
+                false
+            }
+        }.collectLatest { shouldLoadMore ->
+            if (shouldLoadMore && !isLoading) {
+                model.loadMoments()
+            }
+        }
+    }
+    
     LazyVerticalGrid(
         columns = GridCells.Fixed(3),
+        state = gridState,
         modifier = Modifier.fillMaxSize().padding(bottom = 8.dp),
 //        contentPadding = PaddingValues(8.dp)
     ) {
-        items(moments.itemCount) { idx ->
-            val momentItem = moments[idx] ?: return@items
+        items(moments) { momentItem ->
             Box(
                 modifier = Modifier
                     .fillMaxWidth()
@@ -122,7 +148,8 @@ fun DiscoverView() {
                     contentDescription = "",
                     modifier = Modifier
                         .fillMaxSize(),
-                    context = context
+                    context = context,
+                    showShimmer = true
                 )
                 if (momentItem.images.size > 1) {
                     Box(