片段仅显示在右上角答案

【问题标题】：Fragment shows only in top right片段仅显示在右上角
【发布时间】：2021-07-05 18:52:40
【问题描述】：

片段的容器不填充父级（在屏幕截图上）。我有主要活动的 XML，约束布局是片段的容器

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".activities.MainActivity">
    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/main_bottom_nav"/>
    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/main_bottom_nav"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        app:menu="@menu/bottom_navigation_menu"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

对于 Fragment，数据在回收站视图中加载

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/users_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/round_corners"
    tools:context=".fragments.UsersFragment">
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_margin="10dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent">
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/users_recycler_view"
        android:layout_gravity="center_horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    </ScrollView>
    <ProgressBar
        android:id="@+id/users_progress_bar"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

所有布局宽度和高度字段都有“match_parent”，但Fragment只占屏幕的1/4

更新这是recyclerview item的XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/user_card_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <androidx.constraintlayout.widget.ConstraintLayout
            android:id="@+id/user_card_constraint_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/round_corners"
            android:layout_margin="10dp">
    <TextView
        android:id="@+id/first_name_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:textColor="@color/black"
        android:textSize="16sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toStartOf="@id/last_name_text"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

    <TextView
        android:id="@+id/last_name_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="5dp"
        android:textColor="@color/black"
        android:textSize="16sp"
        app:layout_constraintStart_toEndOf="@id/first_name_text"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>
    </androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>

但实际上我在没有 recyclerview 的片段中也有同样的问题

【问题讨论】：

能发一下RecyclerView的item布局吗？
@Zain 更新问题，添加 recyclerview 项目的 xml

标签： android android-layout android-fragments android-constraintlayout

【解决方案1】：

我使用 ViewBinding 功能，这就是问题所在。片段metgod onCreateView 是：

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mBinding = FragmentUsersBinding.inflate(getLayoutInflater());
        return mBinding.getRoot();
    }

要解决这个问题，必须要 attachToParent = false

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mBinding = FragmentUsersBinding.inflate(getLayoutInflater(),container,false);
        return mBinding.getRoot();
    }

【讨论】：