是否可以向 Material DateRangePicker 添加页脚？

Question

我很确定这是不可能的，但我只是想在使用 3rd 方库之前检查一下。 DatePicker 并不能真正让您自定义 UI，它基本上是一个全屏 DialogFragment，因此在上面或下面（甚至在上面）放置一些东西似乎不是一种选择。

我的日历目前如下所示：

但我希望它看起来像这个底部有页脚的设计文档。如果您有任何想法，请告诉我，因为我没有。谢谢！

   val builder = MaterialDatePicker.Builder.dateRangePicker()
      .setTheme(R.style.ThemeOverlay_MaterialComponents_MaterialCalendar_Fullscreen)
      .setCalendarConstraints(
        CalendarConstraints.Builder()
          .setStart(Date().time)
          .setEnd(oneYearFrom().time)
          .setValidator(AvailabilityValidator(it.unavailableDays)).build()
      )
    builder.setInputMode(MaterialDatePicker.INPUT_MODE_CALENDAR)
    builder.build().show(requireActivity().supportFragmentManager, TAG_DATE_RANGE_PICKER)

Answer 1

向MaterialDateRangePicker 添加页脚的唯一方法是访问Picker 根视图，从那里您可以找到Picker FrameLayout Container（ID 为app:id/mtrl_calendar_frame）并访问其子视图@ 987654326@ 包含三个孩子：（Days-GridView、Separator-View 和 RecyclerView）在垂直方向。您想要的是在 RecyclerView 下方添加一个页脚。因为父级是 LinearLayout，所以您可以将 weight 属性添加到其所有子级，使其成为 weight=0，除了 RecyclerView（渲染月份）为 weight=1 以获取所有剩余空间。

要访问 Picker 根视图，您必须观察 MaterialDatePicker (DialogFragment) 生命周期并在 DialogFragment 的 onStart() 中添加页脚视图。为此，您可以使用DefaultLifecycleObserver。

以下是添加页脚视图的完整示例：

private fun showRangeDatePicker() {

    //initialize dateRangePicker
    val builder = MaterialDatePicker.Builder.dateRangePicker()
    builder.setTheme(R.style.ThemeOverlay_MaterialComponents_MaterialCalendar_Fullscreen)

    //set CalendarConstraints
    val constraintsBuilder = CalendarConstraints.Builder()
    val c: Calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"))
    constraintsBuilder.setStart(c.getTimeInMillis())
    c.add(Calendar.YEAR, 1)
    constraintsBuilder.setEnd(c.getTimeInMillis())
    builder.setCalendarConstraints(constraintsBuilder.build())

    //set InputMode and Title
    builder.setInputMode(MaterialDatePicker.INPUT_MODE_CALENDAR)
    builder.setTitleText("Pick dates")

    //get MaterialDatePicker instance and set a lifecycle Observer to listen for DialogFragment lifecycle
    //DefaultLifecycleObserver needs androidx.appcompat:appcompat:1.4.0 and add the FooterView in onStart of DialogFragment
    val picker: MaterialDatePicker<*> = builder.build()
    picker.lifecycle.addObserver(object : DefaultLifecycleObserver
    {
        override fun onCreate(owner: LifecycleOwner) {
        }

        override fun onStart(owner: LifecycleOwner) {
            //add footerView in onStart of DialogFragment so you can access the picker.view
            addMyFooterView(picker)
        }

        override fun onResume(owner: LifecycleOwner) {
        }

        override fun onDestroy(owner: LifecycleOwner) {
            //remove Lifecycle Observer
            picker.lifecycle.removeObserver(this)
        }
    })
    picker.show(supportFragmentManager, picker.toString())
}

private fun addMyFooterView(picker: MaterialDatePicker<*>) {

    //get the MaterialDatePicker root View
    val rootView = picker.view as LinearLayout
    //find the Picker FrameLayout Container with ID: app:id/mtrl_calendar_frame
    val frameLayout = rootView.findViewById<FrameLayout>(resources.getIdentifier("mtrl_calendar_frame", "id", packageName))
    //and get the Picker LinearLayout Container (which contains of 3 children: Days-GridView, Separator-View and a RecyclerView)
    val linearContainer = frameLayout.getChildAt(0) as LinearLayout

    //for each child in Vertical LinearLayout Container set the weight to RecyclerView to 1 and 0 to all others.
    //(This is necessary before adding the footerView to distribute correctly each children Height)
    for (i in 0 until linearContainer.childCount) {
        val v = linearContainer.getChildAt(i)
        val params = v.layoutParams as LinearLayout.LayoutParams
        params.weight = if (v is RecyclerView) 1f else 0f
        v.layoutParams = params
    }

    //and finally add the 4th child in the above linearContainer to be the FooterView
    val myFooterView = layoutInflater.inflate(R.layout.footer_layout, null)
    val myFooterViewHeight = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50f, resources.displayMetrics).toInt()
    myFooterView.layoutParams = LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, myFooterViewHeight, 0f)
    myFooterView.setBackgroundColor(Color.WHITE)
    linearContainer.addView(myFooterView)

    //set any FooterView click listeners
    myFooterView.findViewById<View>(R.id.textView2).setOnClickListener {}
}

footer_layout 是您的自定义页脚 xml 布局，如下所示：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp">

    <View
        android:id="@+id/separatorView"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_alignParentTop="true"
        android:background="@android:color/darker_gray"/>

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:textStyle="bold"
        android:layout_marginEnd="10dp"
        android:layout_centerVertical="true"
        android:layout_alignParentStart="true"
        android:text="Match exact dates" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:textStyle="normal"
        android:layout_marginEnd="10dp"
        android:layout_centerVertical="true"
        android:layout_toEndOf="@+id/textView1"
        android:text="±1 day" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:textStyle="normal"
        android:layout_marginEnd="10dp"
        android:layout_centerVertical="true"
        android:layout_toEndOf="@+id/textView2"
        android:text="±3 days" />

</RelativeLayout>

结果：