如何禁用片段中的后退按钮按下但允许片段本身实现后按逻辑

Question

我有以下 XML -

<androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintLeft_toRightOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/activity_checkout_top_view">

        <LinearLayout
            android:id="@+id/activity_checkout_checkout_stages_viewgroup"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="100dp"
            android:animateLayoutChanges="true"
            android:background="@color/white"
            android:orientation="vertical">

            <FrameLayout
                android:id="@+id/activity_checkout_discount_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:text="@string/activity_checkout_checkout"
                android:textSize="22sp"
                android:textStyle="bold" />

            <LinearLayout
                android:id="@+id/activity_checkout_first_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/activity_checkout_first_stage_textview"
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/color_black"
                    android:gravity="center"
                    android:text="@string/activity_checkout_1"
                    android:textColor="@color/white"
                    android:textStyle="bold" />

                <TextView
                    android:id="@+id/activity_checkout_billing_address_textview"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_billing_address"
                    android:textColor="@color/color_black"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <View
                android:id="@+id/billing_shipping__address_layout_bottom_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />


            <!-- Billing layout -->
            <include
                android:id="@+id/checkout_activity_billing_address_layout_include"
                layout="@layout/fragment_checkout_billing_shipping"
                android:visibility="gone" />

            <FrameLayout
                android:id="@+id/activity_checkout_billing_address_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <LinearLayout
                android:id="@+id/activity_checkout_second_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/activity_checkout_second_stage_textview"
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/activity_checkout_unselected_checkout_stage_color"
                    android:gravity="center"
                    android:text="@string/activity_checkout_2"
                    android:textColor="@color/color_black" />

                <TextView
                    android:id="@+id/activity_checkout_shipping_address_textview"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_shipping_address"
                    android:textColor="@color/activity_checkout_unselected_checkout_stage_color"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <View
                android:id="@+id/activity_checkout_shipping_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />

            <!-- Shipping layout -->
            <include
                android:id="@+id/activity_checkout_shipping_address_layout_include"
                layout="@layout/fragment_checkout_billing_shipping"
                android:visibility="gone" />

            <FrameLayout
                android:id="@+id/activity_checkout_shipping_address_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <LinearLayout
                android:id="@+id/activity_checkout_third_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/activity_checkout_third_stage_textview"
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/activity_checkout_unselected_checkout_stage_color"
                    android:gravity="center"
                    android:text="@string/activity_checkout_3"
                    android:textColor="@color/color_black" />

                <TextView
                    android:id="@+id/activity_checkout_shipping_method_textview"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_shipping_method"
                    android:textColor="@color/activity_checkout_unselected_checkout_stage_color"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <View
                android:id="@+id/activity_checkout_payment_method_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />

            <FrameLayout
                android:id="@+id/activity_checkout_shipping_method_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <LinearLayout
                android:id="@+id/activity_checkout_forth_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/activity_checkout_unselected_checkout_stage_color"
                    android:gravity="center"
                    android:text="@string/activity_checkout_4"
                    android:textColor="@color/color_black" />

                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_payment_method"
                    android:textColor="@color/activity_checkout_unselected_checkout_stage_color"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <View
                android:id="@+id/activity_checkout_payment_information_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />

            <LinearLayout
                android:id="@+id/activity_checkout_fifth_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/activity_checkout_fifth_stage"
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/activity_checkout_unselected_checkout_stage_color"
                    android:gravity="center"
                    android:text="@string/activity_checkout_5"
                    android:textColor="@color/color_black" />

                <TextView
                    android:id="@+id/activity_checkout_payment_information"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_payment_information"
                    android:textColor="@color/activity_checkout_unselected_checkout_stage_color"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>


            <View
                android:id="@+id/activity_checkout_confirm_order_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />

            <FrameLayout
                android:id="@+id/activity_checkout_payment_information_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

            <LinearLayout
                android:id="@+id/activity_checkout_sixth_stage_viewgroup"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:clickable="true"
                android:focusable="true"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/activity_checkout_sixth_stage"
                    android:layout_width="25dp"
                    android:layout_height="25dp"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:layout_marginTop="@dimen/marketplace_15dp"
                    android:background="@color/activity_checkout_unselected_checkout_stage_color"
                    android:gravity="center"
                    android:text="@string/activity_checkout__6"
                    android:textColor="@color/color_black" />

                <TextView
                    android:id="@+id/activity_checkout_confirm_information_textview"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="bottom"
                    android:layout_marginStart="@dimen/marketplace_14dp"
                    android:text="@string/activity_checkout_confirm_information"
                    android:textColor="@color/activity_checkout_unselected_checkout_stage_color"
                    android:textSize="18sp"
                    android:textStyle="bold" />

            </LinearLayout>

            <View
                android:id="@+id/activity_checkout_confirm_information_view"
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:layout_marginStart="@dimen/marketplace_14dp"
                android:layout_marginTop="@dimen/marketplace_15dp"
                android:layout_marginEnd="@dimen/marketplace_14dp"
                android:background="@color/activity_checkout_stages_line" />

            <FrameLayout
                android:id="@+id/activity_checkout_confirm_information_container"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />


        </LinearLayout>


    </androidx.core.widget.NestedScrollView>

看起来像这样 - （这不是图片中显示的整个 XML，而只是与问题相关的一个）

它的工作方式是，对于您在 XML 中看到的每个 FrameLayout，我都会在其中膨胀另一个 Fragment，分别针对每个阶段。

在每个片段中，当我需要从 UI 中关闭该片段时，我调用以下代码 -

activity?.onBackPressed()

这会忽略相关的片段，然后我会弹出一个新片段。

我目前面临的问题是能够通过单次后按关闭片段，这对 UI 很不利。我可以很容易地解除onBackPressed() 能力，但我怎么能告诉每个片段解除自己呢？

我需要一种方法来阻止 Fragment 对 backpress 做出反应，但仍然能够将自己从 backstack 中移除。

Answer 1

当您想要关闭 Fragment 时，请调用 getFragmentManager().popBackStackImmediate() 而不是 onBackPressed()。

Answer 2

使用 BackStack 并推送、弹出片段