在 Android Kotlin 中一天中的不同时间更改片段中的线性布局边距

Question

我正在尝试以编程方式更改 Kotlin 中线性布局的边距，如下所示。但是当我点击页面时应用程序崩溃了。构建过程中没有错误。 我在这里搜索但找不到有效的解决方案。希望能在这里得到答案。谢谢！

class SettingsFragment : Fragment() {      
    private lateinit var linearLayout: LinearLayout

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val view = inflater.inflate(R.layout.fragment_settings, container, false)
        linearLayout = view.findViewById(R.id.myLinearLayout)
        return view
    }    
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        adjustMarginsBasedOnTime()
    }    
    private fun adjustMarginsBasedOnTime() {
        val calendar = Calendar.getInstance()
        val currentHour = calendar.get(Calendar.HOUR_OF_DAY)

        val marginStart: Int
        val marginEnd: Int
        val marginTop: Int
        val marginBottom: Int    
        when (currentHour) {
            in 6..11 -> { // Morning (6 AM - 11 AM)
                marginStart = resources.getDimensionPixelSize(R.dimen.margin_morning_start)
                marginEnd = resources.getDimensionPixelSize(R.dimen.margin_morning_end)
                marginTop = resources.getDimensionPixelSize(R.dimen.margin_morning_top)
                marginBottom = resources.getDimensionPixelSize(R.dimen.margin_morning_bottom)
            }
            in 12..17 -> { // Afternoon (12 PM - 5 PM)
                marginStart = resources.getDimensionPixelSize(R.dimen.margin_afternoon_start)
                marginEnd = resources.getDimensionPixelSize(R.dimen.margin_afternoon_end)
                marginTop = resources.getDimensionPixelSize(R.dimen.margin_afternoon_top)
                marginBottom = resources.getDimensionPixelSize(R.dimen.margin_afternoon_bottom)
            }
            in 18..23 -> { // Evening/Night (6 PM - 5 AM)
                marginStart = resources.getDimensionPixelSize(R.dimen.margin_evening_start)
                marginEnd = resources.getDimensionPixelSize(R.dimen.margin_evening_end)
                marginTop = resources.getDimensionPixelSize(R.dimen.margin_evening_top)
                marginBottom = resources.getDimensionPixelSize(R.dimen.margin_evening_bottom)
            }
            else -> { // Should not happen, but a default case
                marginStart = resources.getDimensionPixelSize(R.dimen.default_margin)
                marginEnd = resources.getDimensionPixelSize(R.dimen.default_margin)
                marginTop = resources.getDimensionPixelSize(R.dimen.default_margin)
                marginBottom = resources.getDimensionPixelSize(R.dimen.default_margin)
            }
        }    
        linearLayout.updateLayoutParams<LinearLayout.LayoutParams> {
            setMargins(marginStart, marginTop, marginEnd, marginBottom)
        }
    }
}

下面是fragment_settings.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/myLinearLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:background="@color/teal_200">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/layout_text"
        android:textColor="@android:color/holo_red_dark"
        android:layout_gravity="center_horizontal"/>

</LinearLayout>

Answer 1

您得到的错误是 FrameLayout LayoutParams 无法转换为 LinearLayout LayoutParams。这意味着该错误是由 LinearLayout 的 LayoutParams 被视为 FrameLayout 的 LayoutParams 引起的。这是您需要的修复。

linearLayout.updateLayoutParams<FrameLayout.LayoutParams> {
  setMargins(marginStart, marginTop, marginEnd, marginBottom)
}

但是，我强烈建议您将 when 语句范围更新为下面的代码，因为您目前尚未涵盖所有 24 小时（0 到 23）

when (currentHour) {
  in 0..11 -> { // Morning (0 AM - 11 AM)

  }
  in 12..17 -> { // Afternoon (12 PM - 5 PM)

  }
  in 18..23 -> { // Evening/Night (6 PM - 5 AM)

  }
  else -> { // Would not happen now!, but a default case

  }
}

最后！就像 CommonsWare 所说，你应该在你的问题中添加错误日志，这样你就可以帮助别人帮助你。

干杯，快乐编码。