diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/components/ChipGroup.kt b/app/src/main/kotlin/cn/super12138/todo/ui/components/ChipGroup.kt
index 6347f87..f8b7524 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/components/ChipGroup.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/components/ChipGroup.kt
@@ -34,10 +34,10 @@ import cn.super12138.todo.utils.VibrationUtils
 @OptIn(ExperimentalLayoutApi::class)
 @Composable
 fun FilterChipGroup(
+    modifier: Modifier = Modifier,
     items: List<ChipItem>,
     defaultSelectedItemIndex: Int = 0,
-    onSelectedChanged: (Int) -> Unit = {},
-    modifier: Modifier = Modifier
+    onSelectedChanged: (Int) -> Unit = {}
 ) {
     val view = LocalView.current
     var selectedItemId by rememberSaveable { mutableIntStateOf(defaultSelectedItemIndex) }
@@ -80,10 +80,8 @@ private fun FilterChipItem(
                 )
             }
         },
-        label = {
-            Text(text)
-        },
-        modifier = Modifier.padding(end = 10.dp)
+        label = { Text(text) },
+        modifier = modifier.padding(end = 10.dp)
     )
 }
 
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
index de24e06..db439df 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/TodoEditorPage.kt
@@ -5,17 +5,17 @@ import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.AnimatedVisibilityScope
 import androidx.compose.animation.ExperimentalSharedTransitionApi
 import androidx.compose.animation.SharedTransitionScope
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.shrinkVertically
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.rememberScrollState
-import androidx.compose.foundation.verticalScroll
+import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.outlined.Undo
 import androidx.compose.material.icons.outlined.Delete
@@ -24,17 +24,11 @@ import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
-import androidx.compose.material3.TextField
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableFloatStateOf
-import androidx.compose.runtime.mutableIntStateOf
-import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.saveable.rememberSaveable
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
@@ -53,6 +47,8 @@ import cn.super12138.todo.ui.components.FilterChipGroup
 import cn.super12138.todo.ui.components.LargeTopAppBarScaffold
 import cn.super12138.todo.ui.pages.editor.components.TodoContentTextField
 import cn.super12138.todo.ui.pages.editor.components.TodoPrioritySlider
+import cn.super12138.todo.ui.pages.editor.components.TodoSubjectTextField
+import cn.super12138.todo.ui.pages.editor.state.rememberEditorState
 import cn.super12138.todo.utils.VibrationUtils
 
 @OptIn(ExperimentalMaterial3Api::class, ExperimentalSharedTransitionApi::class)
@@ -66,34 +62,16 @@ fun TodoEditorPage(
     sharedTransitionScope: SharedTransitionScope,
     animatedVisibilityScope: AnimatedVisibilityScope
 ) {
-    var showExitConfirmDialog by rememberSaveable { mutableStateOf(false) }
-    var showDeleteConfirmDialog by rememberSaveable { mutableStateOf(false) }
-
     val view = LocalView.current
     val context = LocalContext.current
     val scrollBehavior = TopAppBarDefaults.exitUntilCollapsedScrollBehavior()
 
-    var toDoContent by rememberSaveable { mutableStateOf(toDo?.content ?: "") }
-    var isErrorContent by rememberSaveable { mutableStateOf(false) }
-    var selectedSubjectId by rememberSaveable { mutableIntStateOf(toDo?.subject ?: 0) }
-    var subjectContent by rememberSaveable { mutableStateOf(toDo?.customSubject ?: "") }
-    var isErrorSubject by rememberSaveable { mutableStateOf(false) }
-    var priorityState by rememberSaveable { mutableFloatStateOf(toDo?.priority ?: 0f) }
-    var completedSwitchState by rememberSaveable { mutableStateOf(toDo?.isCompleted == true) }
-
-    val isCustomSubject by remember {
-        derivedStateOf { selectedSubjectId == Subjects.Custom.id }
-    }
+    val uiState = rememberEditorState(initialTodo = toDo)
+    val isCustomSubject by remember { derivedStateOf { uiState.selectedSubjectId == Subjects.Custom.id } }
 
     fun checkModifiedBeforeBack() {
-        var isModified = false
-        if ((toDo?.content ?: "") != toDoContent) isModified = true
-        if ((toDo?.subject ?: 0) != selectedSubjectId) isModified = true
-        if ((toDo?.customSubject ?: "") != subjectContent) isModified = true
-        if ((toDo?.priority ?: 0f) != priorityState) isModified = true
-        if ((toDo?.isCompleted == true) != completedSwitchState) isModified = true
-        if (isModified) {
-            showExitConfirmDialog = true
+        if (uiState.isModified()) {
+            uiState.showExitConfirmDialog = true
         } else {
             onNavigateUp()
         }
@@ -115,7 +93,7 @@ fun TodoEditorPage(
                             text = stringResource(R.string.action_delete),
                             expanded = true,
                             containerColor = MaterialTheme.colorScheme.errorContainer,
-                            onClick = { showDeleteConfirmDialog = true },
+                            onClick = { uiState.showDeleteConfirmDialog = true },
                             modifier = Modifier.imePadding()
                         )
                     }
@@ -124,23 +102,12 @@ fun TodoEditorPage(
                         text = stringResource(R.string.action_save),
                         expanded = true,
                         onClick = {
-                            isErrorContent = toDoContent.trim().isEmpty()
-                            isErrorSubject = subjectContent.trim()
-                                .isEmpty() && selectedSubjectId == Subjects.Custom.id
-                            if (isErrorContent || isErrorSubject) return@AnimatedExtendedFloatingActionButton
-
-                            isErrorContent = false
-                            isErrorSubject = false
-                            onSave(
-                                TodoEntity(
-                                    content = toDoContent,
-                                    subject = selectedSubjectId,
-                                    customSubject = subjectContent,
-                                    isCompleted = completedSwitchState,
-                                    priority = priorityState,
-                                    id = toDo?.id ?: 0
-                                )
-                            )
+                            if (uiState.setErrorIfNotValid()) {
+                                return@AnimatedExtendedFloatingActionButton
+                            } else {
+                                uiState.clearError()
+                                onSave(uiState.getEntity())
+                            }
                         },
                         modifier = Modifier
                             .imePadding()
@@ -155,138 +122,129 @@ fun TodoEditorPage(
         onBack = { checkModifiedBeforeBack() },
         modifier = modifier
     ) { innerPadding ->
-        Column(
+        LazyColumn(
+            verticalArrangement = Arrangement.spacedBy(5.dp),
             modifier = Modifier
                 .padding(innerPadding)
                 .padding(horizontal = TodoDefaults.screenPadding)
                 .fillMaxSize()
-                .verticalScroll(rememberScrollState())
         ) {
-            with(sharedTransitionScope) {
-                TodoContentTextField(
-                    value = toDoContent,
-                    onValueChange = { toDoContent = it },
-                    isError = isErrorContent,
-                    modifier = Modifier
-                        .fillMaxWidth()
-                        .sharedBounds(
-                            sharedContentState = rememberSharedContentState("${Constants.KEY_TODO_CONTENT_TRANSITION}_${toDo?.id}"),
-                            animatedVisibilityScope = animatedVisibilityScope
-                        )
-                )
-            }
-
-            Spacer(Modifier.size(5.dp))
-
-            Text(
-                text = stringResource(R.string.label_subject),
-                style = MaterialTheme.typography.titleMedium
-            )
-
-            Spacer(Modifier.size(5.dp))
-
-            val subjects = remember {
-                Subjects.entries.map {
-                    ChipItem(
-                        id = it.id,
-                        text = it.getDisplayName(context)
-                    )
-                }
-            }
-            FilterChipGroup(
-                items = subjects,
-                defaultSelectedItemIndex = toDo?.subject ?: Subjects.Chinese.id,
-                onSelectedChanged = {
-                    selectedSubjectId = it
-                },
-                modifier = Modifier.fillMaxWidth()
-            )
-            AnimatedVisibility(isCustomSubject) {
+            item {
                 with(sharedTransitionScope) {
-                    TextField(
-                        value = subjectContent,
-                        onValueChange = { subjectContent = it },
-                        label = { Text(stringResource(R.string.label_enter_subject_name)) },
-                        isError = isErrorSubject,
-                        supportingText = {
-                            AnimatedVisibility(isErrorSubject) {
-                                Text(stringResource(R.string.error_no_content_entered))
-                            }
-                        },
+                    TodoContentTextField(
+                        value = uiState.toDoContent,
+                        onValueChange = { uiState.toDoContent = it },
+                        isError = uiState.isErrorContent,
                         modifier = Modifier
                             .fillMaxWidth()
                             .sharedBounds(
-                                sharedContentState = rememberSharedContentState("${Constants.KEY_TODO_SUBJECT_TRANSITION}_${toDo?.id}"),
+                                sharedContentState = rememberSharedContentState("${Constants.KEY_TODO_CONTENT_TRANSITION}_${toDo?.id}"),
                                 animatedVisibilityScope = animatedVisibilityScope
                             )
-                            .padding(top = 5.dp)
                     )
                 }
             }
 
-            Spacer(Modifier.size(10.dp))
-
-            Text(
-                text = stringResource(R.string.label_priority),
-                style = MaterialTheme.typography.titleMedium
-            )
-
-            Spacer(Modifier.size(5.dp))
-
-            TodoPrioritySlider(
-                value = priorityState,
-                onValueChange = { priorityState = it },
-            )
-
-            Spacer(Modifier.size(10.dp))
-
-            if (toDo != null) {
+            item {
                 Text(
-                    text = stringResource(R.string.label_more),
+                    text = stringResource(R.string.label_subject),
                     style = MaterialTheme.typography.titleMedium
                 )
 
-                Spacer(Modifier.size(5.dp))
-
-                Row(
-                    verticalAlignment = Alignment.CenterVertically,
+                val subjects = remember {
+                    Subjects.entries.map {
+                        ChipItem(
+                            id = it.id,
+                            text = it.getDisplayName(context)
+                        )
+                    }
+                }
+                FilterChipGroup(
+                    items = subjects,
+                    defaultSelectedItemIndex = toDo?.subject ?: Subjects.Chinese.id,
+                    onSelectedChanged = { uiState.selectedSubjectId = it },
                     modifier = Modifier.fillMaxWidth()
+                )
+                AnimatedVisibility(
+                    visible = isCustomSubject,
+                    enter = fadeIn() + expandVertically(),
+                    exit = fadeOut() + shrinkVertically()
                 ) {
-                    Text(
-                        text = stringResource(R.string.tip_mark_completed),
-                        style = MaterialTheme.typography.labelLarge,
-                        modifier = Modifier.padding(end = 10.dp)
-                    )
-                    Switch(
-                        checked = completedSwitchState,
-                        onCheckedChange = {
-                            completedSwitchState = it
-                            VibrationUtils.performHapticFeedback(view)
-                        }
-                    )
+                    with(sharedTransitionScope) {
+                        TodoSubjectTextField(
+                            value = uiState.subjectContent,
+                            onValueChange = { uiState.subjectContent = it },
+                            isError = uiState.isErrorSubject,
+                            modifier = Modifier
+                                .fillMaxWidth()
+                                .sharedBounds(
+                                    sharedContentState = rememberSharedContentState("${Constants.KEY_TODO_SUBJECT_TRANSITION}_${toDo?.id}"),
+                                    animatedVisibilityScope = animatedVisibilityScope
+                                )
+                        )
+                    }
                 }
             }
 
-            Spacer(Modifier.size(20.dp))
+            item {
+                Text(
+                    text = stringResource(R.string.label_priority),
+                    style = MaterialTheme.typography.titleMedium
+                )
+
+                TodoPrioritySlider(
+                    value = { uiState.priorityState },
+                    onValueChange = { uiState.priorityState = it },
+                )
+            }
+
+            item {
+                if (toDo != null) {
+                    Text(
+                        text = stringResource(R.string.label_more),
+                        style = MaterialTheme.typography.titleMedium
+                    )
+
+                    Row(
+                        verticalAlignment = Alignment.CenterVertically,
+                        modifier = Modifier.fillMaxWidth()
+                    ) {
+                        Text(
+                            text = stringResource(R.string.tip_mark_completed),
+                            style = MaterialTheme.typography.labelLarge,
+                            modifier = Modifier.padding(end = 10.dp)
+                        )
+                        Switch(
+                            checked = uiState.isCompleted,
+                            onCheckedChange = {
+                                VibrationUtils.performHapticFeedback(view)
+                                uiState.isCompleted = it
+                            }
+                        )
+                    }
+                }
+            }
+
+            //Spacer(Modifier.size(20.dp))
         }
     }
 
     ConfirmDialog(
-        visible = showExitConfirmDialog,
+        visible = uiState.showExitConfirmDialog,
         icon = Icons.AutoMirrored.Outlined.Undo,
         text = stringResource(R.string.tip_discard_changes),
         onConfirm = {
-            showExitConfirmDialog = false
+            uiState.showExitConfirmDialog = false
             onNavigateUp()
         },
-        onDismiss = { showExitConfirmDialog = false }
+        onDismiss = { uiState.showExitConfirmDialog = false }
     )
 
     ConfirmDialog(
-        visible = showDeleteConfirmDialog,
+        visible = uiState.showDeleteConfirmDialog,
         icon = Icons.Outlined.Delete,
         text = stringResource(R.string.tip_delete_task, 1),
         onConfirm = onDelete,
-        onDismiss = { showDeleteConfirmDialog = false }
+        onDismiss = { uiState.showDeleteConfirmDialog = false }
     )
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoContentTextField.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
similarity index 61%
rename from app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoContentTextField.kt
rename to app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
index 5078951..44dd0a5 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoContentTextField.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoEditorTextFields.kt
@@ -27,4 +27,25 @@ fun TodoContentTextField(
         },
         modifier = modifier
     )
+}
+
+@Composable
+fun TodoSubjectTextField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    isError: Boolean,
+    modifier: Modifier = Modifier
+) {
+    TextField(
+        value = value,
+        onValueChange = onValueChange,
+        label = { Text(stringResource(R.string.label_enter_subject_name)) },
+        isError = isError,
+        supportingText = {
+            AnimatedVisibility(isError) {
+                Text(stringResource(R.string.error_no_content_entered))
+            }
+        },
+        modifier = modifier
+    )
 }
\ No newline at end of file
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoPrioritySlider.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoPrioritySlider.kt
index 51513a2..4b416bc 100644
--- a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoPrioritySlider.kt
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/components/TodoPrioritySlider.kt
@@ -28,7 +28,7 @@ import cn.super12138.todo.utils.VibrationUtils
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun TodoPrioritySlider(
-    value: Float,
+    value: () -> Float,
     onValueChange: (Float) -> Unit,
     modifier: Modifier = Modifier
 ) {
@@ -39,7 +39,7 @@ fun TodoPrioritySlider(
     val interactionSource = remember { MutableInteractionSource() }
 
     Slider(
-        value = value,
+        value = value(),
         onValueChange = {
             VibrationUtils.performHapticFeedback(view, HapticFeedbackConstants.LONG_PRESS)
             onValueChange(it)
@@ -55,7 +55,7 @@ fun TodoPrioritySlider(
                             .sizeIn(45.dp, 25.dp)
                             .wrapContentWidth()
                     ) {
-                        Text(priorityName[Priority.fromFloat(value).ordinal])
+                        Text(priorityName[Priority.fromFloat(value()).ordinal])
                     }
                 },
                 interactionSource = interactionSource
@@ -66,9 +66,9 @@ fun TodoPrioritySlider(
         modifier = modifier.semantics {
             contentDescription =
                 context.getString(R.string.label_priority) + priorityName[Priority.fromFloat(
-                    value
+                    value()
                 ).ordinal]
-            stateDescription = priorityName[Priority.fromFloat(value).ordinal]
+            stateDescription = priorityName[Priority.fromFloat(value()).ordinal]
             liveRegion = LiveRegionMode.Polite
         }
     )
diff --git a/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt
new file mode 100644
index 0000000..f652190
--- /dev/null
+++ b/app/src/main/kotlin/cn/super12138/todo/ui/pages/editor/state/EditorState.kt
@@ -0,0 +1,113 @@
+package cn.super12138.todo.ui.pages.editor.state
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.SaverScope
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import cn.super12138.todo.logic.database.TodoEntity
+import cn.super12138.todo.logic.model.Subjects
+
+class EditorState(
+    val initialTodo: TodoEntity? = null,
+) {
+    var toDoContent by mutableStateOf(initialTodo?.content ?: "")
+    var isErrorContent by mutableStateOf(false)
+    var selectedSubjectId by mutableIntStateOf(initialTodo?.subject ?: 0)
+    var subjectContent by mutableStateOf(initialTodo?.customSubject ?: "")
+    var isErrorSubject by mutableStateOf(false)
+    var priorityState by mutableFloatStateOf(initialTodo?.priority ?: 0f)
+    var isCompleted by mutableStateOf(initialTodo?.isCompleted == true)
+    var showExitConfirmDialog by mutableStateOf(false)
+    var showDeleteConfirmDialog by mutableStateOf(false)
+
+    /**
+     * 检查待办内容和学科的一者是否无有效，如果无效则为文本框设置错误状态
+     *
+     * @return 它们二者是否都有效。有一者无效就返回 true
+     */
+    fun setErrorIfNotValid(): Boolean {
+        isErrorContent = toDoContent.trim().isEmpty()
+        isErrorSubject = subjectContent.trim().isEmpty() &&
+                selectedSubjectId == Subjects.Custom.id
+        return isErrorContent && isErrorSubject
+    }
+
+    /**
+     * 清除文本框全部错误
+     */
+    fun clearError() {
+        isErrorContent = false
+        isErrorSubject = false
+    }
+
+    /**
+     * 获取编辑后的待办实体
+     *
+     * @return TodoEntity 待办实体
+     */
+    fun getEntity(): TodoEntity = TodoEntity(
+        id = initialTodo?.id ?: 0,
+        content = toDoContent,
+        subject = selectedSubjectId,
+        customSubject = subjectContent,
+        priority = priorityState,
+        isCompleted = isCompleted
+    )
+
+    /**
+     * 检查待办是否被编辑修改
+     */
+    fun isModified(): Boolean {
+        var isModified = false
+        if ((initialTodo?.content ?: "") != toDoContent) isModified = true
+        if ((initialTodo?.subject ?: 0) != selectedSubjectId) isModified = true
+        if ((initialTodo?.customSubject ?: "") != subjectContent) isModified = true
+        if ((initialTodo?.priority ?: 0f) != priorityState) isModified = true
+        if ((initialTodo?.isCompleted == true) != isCompleted) isModified = true
+        return isModified
+    }
+
+    /**
+     * 保存状态的 Saver 对象，用于适配 rememberSaveable
+     */
+    object Saver : androidx.compose.runtime.saveable.Saver<EditorState, Any> {
+        override fun SaverScope.save(value: EditorState): Any? {
+            return listOf(
+                value.initialTodo?.id ?: 0,
+                value.toDoContent,
+                value.isErrorContent,
+                value.selectedSubjectId,
+                value.subjectContent,
+                value.isErrorSubject,
+                value.priorityState,
+                value.isCompleted,
+                value.showExitConfirmDialog,
+                value.showDeleteConfirmDialog
+            )
+        }
+
+        override fun restore(value: Any): EditorState? {
+            val list = value as List<*>
+            val initialTodo = list[0] as? TodoEntity?
+            return EditorState(initialTodo).apply {
+                toDoContent = list[1] as String
+                isErrorContent = list[2] as Boolean
+                selectedSubjectId = list[3] as Int
+                subjectContent = list[4] as String
+                isErrorSubject = list[5] as Boolean
+                priorityState = list[6] as Float
+                isCompleted = list[7] as Boolean
+                showExitConfirmDialog = list[8] as Boolean
+                showDeleteConfirmDialog = list[9] as Boolean
+            }
+        }
+    }
+}
+
+@Composable
+fun rememberEditorState(initialTodo: TodoEntity? = null): EditorState =
+    rememberSaveable(saver = EditorState.Saver) { EditorState(initialTodo) }
\ No newline at end of file