修复添加Agent时取消选择头像后数据被清空的问题

- 引入`isSelectingAvatar`状态来标记是否正在选择头像。
- 当用户从图片裁剪页面返回或取消选择时，不再清空`AddAgentViewModel`中的数据。
- 仅当用户从`AddAgent`页面返回（并且不是在选择头像的过程中）时，才清空已填写的数据。
- 调整了`AddAgent`页面的返回逻辑，以确保在选择头像过程中返回时数据得以保留。

app/src/main/java/com/aiosman/ravenow/ui/agent/AddAgent.kt

@@ -25,6 +25,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
+import androidx.activity.compose.BackHandler
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
@@ -44,6 +45,14 @@ import com.aiosman.ravenow.ui.account.AccountEditViewModel
 import com.aiosman.ravenow.ui.comment.NoticeScreenHeader
 import com.aiosman.ravenow.ui.comment.ScreenHeader
 import com.aiosman.ravenow.ui.comment.ScreenHeader2
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Row
+import androidx.compose.ui.graphics.ColorFilter
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
 import com.aiosman.ravenow.ui.composables.ActionButton
 import com.aiosman.ravenow.ui.composables.CustomAsyncImage
 import com.aiosman.ravenow.ui.composables.StatusBarSpacer
@@ -89,11 +98,18 @@ fun AddAgentScreen() {
     }
 
 
-    // 页面退出时清空数据
-    DisposableEffect(Unit) {
-        onDispose {
+    // 处理系统返回键
+    BackHandler {
+        // 如果不是在选择头像过程中，则清空数据
+        if (!model.isSelectingAvatar) {
             model.clearData()
         }
+        navController.popBackStack()
+    }
+    
+    // 页面进入时重置头像选择状态
+    LaunchedEffect(Unit) {
+        model.isSelectingAvatar = false
     }
     
     Column(
@@ -107,18 +123,46 @@ fun AddAgentScreen() {
             modifier = Modifier.padding(horizontal = 24.dp, vertical = 16.dp)
                 .background(color = appColors.decentBackground)
         ) {
-            ScreenHeader2 (
-                title = stringResource(R.string.agent_add),
-                moreIcon = false
+            // 自定义header，控制返回按钮行为
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                verticalAlignment = Alignment.CenterVertically,
             ) {
+                Image(
+                    painter = painterResource(id = R.drawable.rider_pro_back_icon),
+                    contentDescription = "返回",
+                    modifier = Modifier.size(24.dp).clickable(
+                        indication = null,
+                        interactionSource = remember { MutableInteractionSource() }
+                    ) {
+                        // 与BackHandler保持一致的逻辑
+                        if (!model.isSelectingAvatar) {
+                            model.clearData()
+                        }
+                        navController.navigateUp()
+                    },
+                    colorFilter = ColorFilter.tint(appColors.text)
+                )
+                Spacer(modifier = Modifier.size(12.dp))
+                Text(
+                    stringResource(R.string.agent_add),
+                    fontWeight = FontWeight.W600,
+                    modifier = Modifier.weight(1f),
+                    textAlign = TextAlign.Center,
+                    fontSize = 17.sp,
+                    color = appColors.text
+                )
+                Spacer(modifier = Modifier.size(12.dp))
                 Icon(
                     modifier = Modifier
                         .size(24.dp)
-
                         .noRippleClickable {
+                            // 提交创建智能体的逻辑可以在这里实现
                         },
                     imageVector = Icons.Default.Check,
-                    contentDescription = "Add")
+                    contentDescription = "Add",
+                    tint = appColors.text
+                )
             }
         }
         Spacer(modifier = Modifier.height(44.dp))
@@ -146,6 +190,8 @@ fun AddAgentScreen() {
                         .background(appColors.main)
                         .align(Alignment.BottomEnd)
                         .noRippleClickable {
+                            // 设置正在选择头像的标志
+                            model.isSelectingAvatar = true
                             navController.navigate(NavigationRoute.AgentImageCrop.route)
                         },
                     contentAlignment = Alignment.Center

app/src/main/java/com/aiosman/ravenow/ui/agent/AddAgentViewModel.kt

@@ -23,7 +23,7 @@ object AddAgentViewModel : ViewModel() {
     var desc by mutableStateOf("")
     var croppedBitmap by mutableStateOf<Bitmap?>(null)
     var isUpdating by mutableStateOf(false)
-    var isFromAddAgent by mutableStateOf(false)
+    var isSelectingAvatar by mutableStateOf(false) // 标记是否正在选择头像
 
     suspend fun updateAgentAvatar(context: Context) {
         croppedBitmap?.let {
@@ -83,6 +83,6 @@ object AddAgentViewModel : ViewModel() {
         desc = ""
         croppedBitmap = null
         isUpdating = false
-        isFromAddAgent = false
+        isSelectingAvatar = false
     }
 }

app/src/main/java/com/aiosman/ravenow/ui/agent/AgentImageCropScreen.kt

@@ -83,6 +83,8 @@ fun AgentImageCropScreen() {
             }
         }
         if (uri == null) {
+            // 用户取消选择图片，重置标志
+            AddAgentViewModel.isSelectingAvatar = false
             navController.popBackStack()
         }
     }
@@ -119,6 +121,8 @@ fun AgentImageCropScreen() {
                 painter = painterResource(R.drawable.rider_pro_back_icon),
                 contentDescription = null,
                 modifier = Modifier.clickable {
+                    // 用户取消头像选择，重置标志
+                    AddAgentViewModel.isSelectingAvatar = false
                     navController.popBackStack()
                 },
                 colorFilter = ColorFilter.tint(Color.White)
@@ -134,6 +138,8 @@ fun AgentImageCropScreen() {
                     if (croppedBitmap != null) {
                         // 如果已经有裁剪结果，直接返回
                         AddAgentViewModel.croppedBitmap = croppedBitmap
+                        // 重置头像选择标志
+                        AddAgentViewModel.isSelectingAvatar = false
                         AddAgentViewModel.viewModelScope.launch {
                             AddAgentViewModel.updateAgentAvatar(context)
                             navController.popBackStack()