Android中BottomSheetDialogFragment横屏无法match_parent问题求助

Android中使用BottomSheetDialogFragment时，竖屏状态下内容可以match_parent全屏显示，但横屏时左右会出现莫名边距，无法铺满屏幕。

核心矛盾：该现象由使用Theme.Material3主题导致。若单独为BottomSheet切换到Theme.Design主题，虽然能让内容填充父布局，但会引发新问题——BottomSheet的颜色无法与当前Material You主题匹配，且手动设置内容颜色也无法生效。

测试基于全新工程（无额外修改），效果表现：

• 竖屏：内容全屏显示，无左右边距
• 横屏：内容左右存在明显边距，未铺满屏幕

用到的代码如下：

布局文件（sheet_test.xml） #

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="0dp"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Hello, World!"
        android:textSize="100sp"
        android:gravity="center"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="Hello, World!"
        android:textSize="100sp"
        android:gravity="center"/>
</LinearLayout>

触发显示BottomSheet的代码 #

TestSheet().show(supportFragmentManager, TestSheet::class.java.canonicalName)

TestSheet类实现 #

class TestSheet : BottomSheetDialogFragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val v = inflater.inflate(R.layout.sheet_test, container, false)
        (dialog as BottomSheetDialog).let {
            it.behavior.state = BottomSheetBehavior.STATE_EXPANDED
            it.behavior.skipCollapsed = true
            it.behavior.isDraggable = true
            dialog?.window?.clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND)
            dialog?.window?.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS)
        }
        return v
    }
}

需求：让BottomSheetDialogFragment在横屏时全屏显示，同时保留Material You主题的颜色。

针对Material3主题下的BottomSheet横屏边距问题，以下方案可在保留Material You样式的前提下解决全屏需求：

方案1：自定义Material3风格的BottomSheet主题 #

在res/values/styles.xml中添加自定义主题，继承Material3的BottomSheetDialog主题，直接覆盖布局相关属性：

<!-- 自定义全屏BottomSheetDialog主题 -->
<style name="FullScreenBottomSheetDialogTheme" parent="Theme.Material3.BottomSheetDialog">
    <item name="bottomSheetStyle">@style/FullScreenBottomSheet</item>
</style>

<!-- 定义全屏BottomSheet样式 -->
<style name="FullScreenBottomSheet" parent="Widget.Material3.BottomSheet">
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">match_parent</item>
    <item name="behavior_expandedOffset">0dp</item> <!-- 移除展开时的偏移 -->
    <item name="android:padding">0dp</item> <!-- 清除默认内边距 -->
</style>

然后在TestSheet中指定该主题：

class TestSheet : BottomSheetDialogFragment() {

    // 重写onCreateDialog指定自定义主题
    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        return BottomSheetDialog(requireContext(), R.style.FullScreenBottomSheetDialogTheme)
    }

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val v = inflater.inflate(R.layout.sheet_test, container, false)
        (dialog as BottomSheetDialog).let {
            it.behavior.state = BottomSheetBehavior.STATE_EXPANDED
            it.behavior.skipCollapsed = true
            it.behavior.isDraggable = true
            dialog?.window?.clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND)
        }
        return v
    }
}

方案2：代码动态调整父布局参数 #

如果不想自定义主题，可在onViewCreated中直接修改BottomSheet的父容器布局参数，清除默认边距：

class TestSheet : BottomSheetDialogFragment() {

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.sheet_test, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        // 获取BottomSheet的直接父容器
        val bottomSheetParent = view.parent as View
        // 设置父容器为全屏
        bottomSheetParent.layoutParams = ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.MATCH_PARENT
        )
        // 清除父容器的默认内边距
        bottomSheetParent.setPadding(0, 0, 0, 0)

        // 保持原有Behavior设置
        (dialog as BottomSheetDialog).let {
            it.behavior.state = BottomSheetBehavior.STATE_EXPANDED
            it.behavior.skipCollapsed = true
            it.behavior.isDraggable = true
            dialog?.window?.clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND)
        }
    }
}

方案3：调整Window布局参数（适配Android 11+） #

通过修改Window的布局参数，强制让BottomSheet铺满屏幕：

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    dialog?.window?.let { window ->
        // 设置窗口为全屏尺寸
        window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
        // 清除窗口的默认边距
        window.decorView.setPadding(0, 0, 0, 0)
    }

    // 原有Behavior配置
    (dialog as BottomSheetDialog).let {
        it.behavior.state = BottomSheetBehavior.STATE_EXPANDED
        it.behavior.skipCollapsed = true
        it.behavior.isDraggable = true
        dialog?.window?.clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND)
    }
}

以上三种方案均不会破坏Material You主题的颜色适配，可根据项目需求选择合适的实现方式。

内容的提问来源于stack exchange，提问作者Mohammad Elsayed