如何修复Material3展开状态SearchBar拦截返回手势的问题？

问题 #

在Android项目中使用处于expanded状态的androidx.compose.material3.SearchBar，依赖版本为androidx.compose:compose-bom:2024.09.02（包含androidx.compose.material3:material3-*:1.3.0）。当前遇到的问题是：SearchBar会消耗返回手势，导致用户无法离开当前页面（替换为其他普通组件后该现象消失）。

相关代码结构如下：

SearchActivity.kt #

class SearchActivity {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_search)
        if (savedInstanceState == null) {
            addFragment(R.id.container, SearchFragment(), SearchFragment.FRAGMENT_TAG)
        }
    }
}

layout/activity_search.xml #

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:context=".search.SearchActivity"
        tools:ignore="MergeRootFrame"
        tools:layout="@layout/fragment_search" />

</androidx.constraintlayout.widget.ConstraintLayout>

SearchFragment.kt #

class SearchFragment : Fragment() {

    companion object {
        const val FRAGMENT_TAG = "SEARCH_FRAGMENT_TAG"

        fun replaceAtBackStack(fragmentManager: FragmentManager, @IdRes containerViewId: Int) {
            fragmentManager.commit {
                fragmentManager.popBackStack(FRAGMENT_TAG, FragmentManager.POP_BACK_STACK_INCLUSIVE)
                fragmentManager.replaceFragment(containerViewId, SearchFragment(), FRAGMENT_TAG, FRAGMENT_TAG)
            }
        }
    }

    private val viewModelFactory by lazy { SearchViewModelFactory(/*...*/) }
    private val viewModel: SearchViewModel by viewModels { viewModelFactory }

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View = 
      inflater.inflate(R.layout.fragment_search, container, false).apply {
        findViewById<ComposeView>(R.id.search_view).apply {
            setViewCompositionStrategy(DisposeOnViewTreeLifecycleDestroyed)
            setContent {
                SearchScreen(
                    searchQuery = viewModel.searchQuery,
                    state = viewModel.searchResultsState.collectAsState().value,
                    onViewEvent = viewModel::onViewEvent,
                )
            }
            isClickable = true
        }
    }

}

layout/fragment_search.xml #

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.compose.ui.platform.ComposeView
        android:id="@+id/search_view"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

SearchScreen.kt #

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun SearchScreen(
    searchQuery: String,
    state: SearchResultState,
    onViewEvent: (SearchViewEvent) -> Unit,
) {
    MyTheme {
        Scaffold { contentPadding ->
            Box(
                Modifier
                    .padding(contentPadding)
            ) {
                var text by rememberSaveable { mutableStateOf(searchQuery) }
                val expanded = true
                SearchBar(
                    modifier = Modifier
                        .align(TopCenter)
                        .semantics { traversalIndex = 0f },
                    inputField = {
                        SearchBarDefaults.InputField(
                            query = text,
                            onQueryChange = {
                                text = it
                                onViewEvent(OnSearchQueryChange(it))
                            },
                            onSearch = { },
                            expanded = expanded,
                            onExpandedChange = { },
                            placeholder = { Text(stringResource(R.string.search_query_hint)) },
                            leadingIcon = { Icon(Icons.Default.Search, contentDescription = null) },
                        )
                    },
                    expanded = expanded,
                    onExpandedChange = { }
                ) {
                    when (state) {
                        is Loading -> Loading()
                        is Success -> {
                            val sessions = state.parameters
                            if (sessions.isEmpty()) {
                                NoSearchResult()
                            } else {
                                SearchResultList(
                                    parameters = sessions,
                                    onViewEvent = onViewEvent,
                                )
                            }
                        }
                    }
                }
            }
        }
    }
}

解决方案 #

这个问题源于Material3的SearchBar在expanded状态下会拦截系统返回手势，可通过以下方式修复：

方案一：手动处理返回事件 #

在SearchFragment中监听返回键，根据SearchBar的展开状态决定是收缩组件还是允许页面返回：

1. 修改SearchScreen，将expanded状态改为可外部控制：

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun SearchScreen(
    searchQuery: String,
    state: SearchResultState,
    onViewEvent: (SearchViewEvent) -> Unit,
    isExpanded: Boolean,
    onExpandedChange: (Boolean) -> Unit,
) {
    MyTheme {
        Scaffold { contentPadding ->
            Box(
                Modifier
                    .padding(contentPadding)
            ) {
                var text by rememberSaveable { mutableStateOf(searchQuery) }
                SearchBar(
                    modifier = Modifier
                        .align(TopCenter)
                        .semantics { traversalIndex = 0f },
                    inputField = {
                        SearchBarDefaults.InputField(
                            query = text,
                            onQueryChange = {
                                text = it
                                onViewEvent(OnSearchQueryChange(it))
                            },
                            onSearch = { },
                            expanded = isExpanded,
                            onExpandedChange = onExpandedChange,
                            placeholder = { Text(stringResource(R.string.search_query_hint)) },
                            leadingIcon = { Icon(Icons.Default.Search, contentDescription = null) },
                        )
                    },
                    expanded = isExpanded,
                    onExpandedChange = onExpandedChange
                ) {
                    when (state) {
                        is Loading -> Loading()
                        is Success -> {
                            val sessions = state.parameters
                            if (sessions.isEmpty()) {
                                NoSearchResult()
                            } else {
                                SearchResultList(
                                    parameters = sessions,
                                    onViewEvent = onViewEvent,
                                )
                            }
                        }
                    }
                }
            }
        }
    }
}

2. 在SearchFragment中管理状态并监听返回事件：

class SearchFragment : Fragment() {

    // ... 原有代码

    private var isSearchExpanded by mutableStateOf(true)

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View = 
      inflater.inflate(R.layout.fragment_search, container, false).apply {
        findViewById<ComposeView>(R.id.search_view).apply {
            setViewCompositionStrategy(DisposeOnViewTreeLifecycleDestroyed)
            setContent {
                SearchScreen(
                    searchQuery = viewModel.searchQuery,
                    state = viewModel.searchResultsState.collectAsState().value,
                    onViewEvent = viewModel::onViewEvent,
                    isExpanded = isSearchExpanded,
                    onExpandedChange = { isSearchExpanded = it }
                )
            }
            isClickable = true
        }
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner) {
            if (isSearchExpanded) {
                isSearchExpanded = false
            } else {
                isEnabled = false
                requireActivity().onBackPressedDispatcher.onBackPressed()
            }
        }
    }
}

方案二：禁用SearchBar的手势拦截 #

通过修饰符让SearchBar不拦截左侧区域的返回手势：

SearchBar(
    modifier = Modifier
        .align(TopCenter)
        .semantics { traversalIndex = 0f }
        .interceptTouchEvent { _, event ->
            // 仅当触摸点不在左侧返回区域时，才拦截事件
            event.action == MotionEvent.ACTION_MOVE && event.x >= 100
        },
    // ... 原有参数
) {
    // ... 原有内容
}

方案三：升级Compose版本 #

该问题可能是Material3 1.3.0的已知bug，尝试升级到更高版本的Compose BOM：

implementation platform("androidx.compose:compose-bom:2024.10.00")
implementation "androidx.compose.material3:material3"

内容的提问来源于stack exchange，提问作者JJD