Question

我正在使用回收站视图向我的视图动态添加项目。

这是 frame_layout ，我在其中定义回收站视图的尺寸

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    android:clickable="true"
    tools:context=".CategoriesFragment">
<RelativeLayout
        android:id="@+id/categories_fruits_clicked"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/categories_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>


    </RelativeLayout>

</FrameLayout>

这是 recycler_view_list_item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">


        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="150dp"
            android:background="@drawable/product_background"  <!--a blue colored background, with rounded corners-->
            android:layout_margin="16dp">

            <ImageView
                android:id="@+id/product_imageView"
                android:layout_marginTop="15dp"
                android:layout_width="120dp"
                android:layout_height="120dp"/>

            <TextView
                android:id="@+id/textViewTitle"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentTop="true"
                android:layout_marginTop="16dp"
                android:layout_marginStart="16dp"
                android:layout_toEndOf="@id/product_imageView"
                android:text="Banana"
                android:fontFamily="@font/baloo"
                android:textSize="20sp"
                android:textColor="@color/colorAccent" />

            <TextView
                android:id="@+id/textViewPrice"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@id/textViewTitle"
                android:layout_marginStart="16dp"
                android:layout_toEndOf="@id/product_imageView"
                android:text="Rs 120"
                android:textStyle="bold"
                android:textColor="@color/green"/>
            <Button
                android:id="@+id/qty_minus"
                android:background="@null"
                android:text="-"
                android:textColor="@color/red"
                android:textSize="20sp"
                android:layout_width="40dp"
                android:layout_height="40dp"
                android:layout_below="@+id/textViewPrice"
                android:layout_toEndOf="@id/product_imageView"
                android:layout_margin="16dp"/>

            <TextView
                android:id="@+id/qty_counter"
                android:text="1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_below="@+id/textViewPrice"
                android:layout_toEndOf="@id/qty_minus"
                android:layout_marginTop="26dp"
                android:layout_marginEnd="10dp"/>

            <Button
                android:id="@+id/qty_plus"
                android:background="@null"
                android:text="+"
                android:textColor="@color/red"
                android:textSize="20sp"
                android:layout_width="40dp"
                android:layout_height="40dp"
                android:layout_below="@+id/textViewPrice"
                android:layout_toEndOf="@id/qty_counter"
                android:layout_marginTop="16dp"/>

        </RelativeLayout>


</LinearLayout>

出于某种奇怪的原因，回收站视图并未覆盖整个屏幕宽度，尽管将其定义为“ match_parent”。令人惊讶的是，预览显示正确，蓝色背景在布局宽度上分布，但是，在我的设备中，预览仅显示与包装内容一样大的内容。

当我将recycler_view_list_item的“相对布局”中的layout_width更改为400dp时，它将覆盖整个屏幕的宽度。 match_parent在哪里出问题？

修改1： 我的 ProductRecyclerViewAdapter

public class ProductRecyclerViewAdapter extends RecyclerView.Adapter<ProductRecyclerViewAdapter.ProductViewHolder> {

    private Context context;
    private List<Product> productList;

    public ProductRecyclerViewAdapter(Context context, List<Product> productList) {
        this.context = context;
        this.productList = productList;
    }

    @NonNull
    @Override
    public ProductViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.product_recyclerview_list_item,null);
        ProductViewHolder holder = new ProductViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull ProductViewHolder prouctViewHolder, int i) {
        Product product = productList.get(i);
        prouctViewHolder.pdtTitle.setText(product.getTitle());
        prouctViewHolder.pdtPrice.setText("MRP Rs " + String.valueOf(product.getPrice()));
        prouctViewHolder.pdtImageView.setImageDrawable(context.getResources().getDrawable(product.getImageId()));

    }

    @Override
    public int getItemCount() {
        return productList.size();
    }

    class ProductViewHolder extends RecyclerView.ViewHolder{

        ImageView pdtImageView;
        TextView pdtTitle, pdtPrice;

        public ProductViewHolder(@NonNull View itemView) {
            super(itemView);
            pdtImageView = itemView.findViewById(R.id.product_imageView);
            pdtTitle = itemView.findViewById(R.id.textViewTitle);
            pdtPrice = itemView.findViewById(R.id.textViewPrice);
        }
    }
}

编辑2：添加了图像

预览（上方）

在我的设备中（上面）该怎么看

Answer 1

尝试此操作，将“相对”布局更改为线性布局，并将布局权重设置为1

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    android:clickable="true"
    tools:context=".CategoriesFragment">
<LinearLayout
        android:id="@+id/categories_fruits_clicked"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/categories_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" 
        android:layout_weight="1"/>
    </RelativeLayout>

</FrameLayout>

Answer 2

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

使用项目布局的匹配父级高度和

LayoutInflater.from(getContext()).inflate(R.layout.recycler_view_list_item, parent, false)

由于某些怪异的原因，match_parent用作wrap_content

2 个答案: