Fragment中RecyclerView无法显示的问题求助

安全阿岳

2026-4-20

大家好，我尝试在Fragment里添加RecyclerView但一直没成功，跟着原本适配MainActivity的教程改了代码，可RecyclerView就是不显示。已经查过类似问题还是没解决，麻烦帮我看看哪里出问题了。

我的布局和代码如下：

fragment_add_recipe.xml（RecyclerView所在布局）

<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView 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=".AddRecipeFragment">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="16dp">

        <com.google.android.material.textfield.TextInputLayout
            android:id="@+id/recipe_name_text_input_layout"
            style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toTopOf="parent">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/recipe_name_text_input"
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:inputType="text"
                android:hint="@string/recipe_name_hint"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintBottom_toBottomOf="parent"/>
        </com.google.android.material.textfield.TextInputLayout>

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/ingredient_row_recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:itemCount="5"
            tools:listitem="@layout/ingredient_row_view"
            app:layout_constraintTop_toBottomOf="@id/recipe_name_text_input_layout"/>

        <Button
            android:id="@+id/save_recipe_button"
            android:layout_width="150sp"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_marginTop="20sp"
            android:text="Save"
            android:textColor="#ffffff"
            android:textSize="20sp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintTop_toBottomOf="@id/ingredient_row_recycler_view"
            app:layout_constraintBottom_toBottomOf="parent"/>
    </androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

AddRecipeFragment.kt

package com.example.recipy

import CustomAdapter
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.databinding.DataBindingUtil
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.recipy.databinding.FragmentAddRecipeBinding

class AddRecipeFragment : Fragment() {

    private var _binding: FragmentAddRecipeBinding? = null
    //    For the ingredient row
    private val ingredientList : ArrayList<IngredientRowViewModel> = ArrayList()
    private lateinit var customAdapter : CustomAdapter
    private val binding get() = _binding!!

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the Fragment layout
        _binding = FragmentAddRecipeBinding.inflate(inflater, container, false)
        setAdapter()
        return binding.root
    }

    private fun setAdapter(){
        customAdapter = CustomAdapter(ingredientList)
        binding.ingredientRowRecyclerView.apply {
            layoutManager = LinearLayoutManager(requireContext())
            adapter = customAdapter
        }
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        // Make button save the recipe in the SQL db
        binding.saveRecipeButton.setOnClickListener{
            //            Some code for SQL connection here
        }
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

IngredientRowViewModel.kt

package com.example.recipy

data class IngredientRowViewModel(var ingredient: String) {
}

CustomAdapter.kt

import android.view.LayoutInflater
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import com.example.recipy.IngredientRowViewModel
import com.example.recipy.R
import com.example.recipy.databinding.IngredientRowViewBinding

class CustomAdapter(private val ingredientList: ArrayList<IngredientRowViewModel>) : RecyclerView.Adapter<CustomAdapter.IngredientRowViewHolder>() {

    inner class IngredientRowViewHolder(private val binding : IngredientRowViewBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(ingredient : IngredientRowViewModel){
            binding.ingredient = ingredient
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): IngredientRowViewHolder =
        IngredientRowViewHolder(IngredientRowViewBinding.inflate(LayoutInflater.from(parent.context), parent, false))

    override fun onBindViewHolder(holder: IngredientRowViewHolder, position: Int) {
        holder.bind(ingredientList[position])
    }

    override fun getItemCount(): Int {
        return ingredientList.size
    }
}

ingredient_row_view.xml

<?xml version="1.0" encoding="utf-8"?>
<layout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <variable
            name="ingredient"
            type="com.example.recipy.IngredientRowViewModel" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:padding="5dp">

        <com.google.android.material.textfield.TextInputLayout
            android:id="@+id/ingredient_name_text_input_layout"
            style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toTopOf="parent">

            <com.google.android.material.textfield.TextInputEditText
                android:id="@+id/ingredient_name_text_input"
                android:layout_height="wrap_content"
                android:layout_width="match_parent"
                android:inputType="text"
                android:hint="@string/ingredient_name_hint"
                app:layout_constraintTop_toTopOf="parent"
                app:layout_constraintBottom_toBottomOf="parent"/>
        </com.google.android.material.textfield.TextInputLayout>
    </LinearLayout>
</layout>

我排查到的几个可能问题及解决办法：

问题1：RecyclerView的数据源是空的
你的ingredientList初始化后没有添加任何数据，CustomAdapter的getItemCount()返回0，RecyclerView自然没有内容可显示。可以先手动加几条测试数据试试：

private fun setAdapter(){
    // 先添加测试数据
    ingredientList.add(IngredientRowViewModel("鸡蛋"))
    ingredientList.add(IngredientRowViewModel("面粉"))
    customAdapter = CustomAdapter(ingredientList)
    binding.ingredientRowRecyclerView.apply {
        layoutManager = LinearLayoutManager(requireContext())
        adapter = customAdapter
    }
}

问题2：RecyclerView的布局约束和高度设置有问题
你的RecyclerView在ConstraintLayout里设置了android:layout_height="match_parent"，同时外层是NestedScrollView，这会导致RecyclerView无限延伸，把下方的Save按钮挤出去，而且本身也无法正确计算高度。建议修改RecyclerView的布局属性：

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/ingredient_row_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="0dp" <!-- 改成0dp，用约束控制高度 -->
    tools:itemCount="5"
    tools:listitem="@layout/ingredient_row_view"
    app:layout_constraintTop_toBottomOf="@id/recipe_name_text_input_layout"
    app:layout_constraintBottom_toTopOf="@id/save_recipe_button" <!-- 添加底部约束，和按钮隔开 -->
    app:layout_constraintVertical_bias="0" />

另外，NestedScrollView里的ConstraintLayout高度可以改成wrap_content，避免不必要的滚动冲突。

问题3：数据绑定未正确关联到EditText
你的ingredient_row_view.xml里的TextInputEditText没有绑定ingredient的ingredient字段，即使有数据也不会显示。需要给EditText加上绑定：

<com.google.android.material.textfield.TextInputEditText
    android:id="@+id/ingredient_name_text_input"
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:inputType="text"
    android:hint="@string/ingredient_name_hint"
    android:text="@{ingredient.ingredient}" <!-- 添加这行数据绑定 -->
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintBottom_toBottomOf="parent"/>

备注：内容来源于stack exchange，提问作者gitcanzo

Fragment中RecyclerView无法显示的问题求助

我的布局和代码如下： #

fragment_add_recipe.xml（RecyclerView所在布局）

AddRecipeFragment.kt

IngredientRowViewModel.kt

CustomAdapter.kt

ingredient_row_view.xml

我排查到的几个可能问题及解决办法： #

我的布局和代码如下：

我排查到的几个可能问题及解决办法：