相关疑难解决方法(0)

我必须分割折扣片段并编辑显示在“编辑服务”活动中的服务片段。当我返回编辑服务片段时，折扣片段上显示的后退箭头消失了我想显示它以从编辑服务活动中导航上一个活动。

活动布局 ..................................... …………

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout 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.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <androidx.appcompat.widget.Toolbar

            android:id="@+id/toolbar_hesham"
            android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            app:title="@string/edit_service"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            android:minHeight="?attr/actionBarSize"
            app:layout_constraintTop_toTopOf="parent" />

        <fragment
            android:id="@+id/nav_host_edit_service"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            app:layout_constraintTop_toBottomOf="@+id/toolbar_hesham"
            app:layout_constraintBottom_toBottomOf="parent"
            app:defaultNavHost="true"
            app:navGraph="@navigation/edit_service_nav" />
    </androidx.constraintlayout.widget.ConstraintLayout>


    <include layout="@layout/confirm_request_bottom_sheet"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

活动代码 ..................................... ………………

public class EditServicesActivity extends BaseActivity<MainViewModel> {


    public Toolbar toolbar;
    public NavController navController;

    @Override
    protected void initActivityComponent() {
        component = ProServeTechApp.getComponent(this)
                .plus(new ActivityModule(this));
        component.inject(this);
    }

    @Override
    protected int getLayout() {
        return R.layout.activity_edit_services;
    }

    @Override
    protected Class<MainViewModel> getViewModelClass() { …