CardView高程不适用于RecyclerView

Question

在单独的应用程序中测试时，CardView高程可以正常工作，但是当使用cardView的相同代码来制作RecyclerView的项目时，不再出现高程。

以下是RecyclerView列表项的代码：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:layout_height="wrap_content"
             android:layout_width="match_parent"
             xmlns:android="http://schemas.android.com/apk/res/android"
             xmlns:card_view="http://schemas.android.com/apk/res-auto"
             xmlns:app="http://schemas.android.com/apk/res-auto"
             android:layout_margin="10dp">


<android.support.v7.widget.CardView
    android:id="@+id/card_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorAccent"
    card_view:cardUseCompatPadding="true"
    app:cardMaxElevation="6dp"
    card_view:cardCornerRadius="3dp"
    card_view:cardElevation="24dp">

    <LinearLayout android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/thumbnail"
            android:layout_width="match_parent"
            android:layout_height="250dp" />

        <TextView
            android:id="@+id/title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/thumbnail"
            />
    </LinearLayout>


</android.support.v7.widget.CardView>

这是我的主要活动xml：

<?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="wrap_content"
                   android:orientation="vertical"
                   android:background="@drawable/bitmap"
                   android:layerType="software"
                   android:padding="10dp"
    tools:context="com.example.android.vikramadityastimeline.MainActivity">

<android.support.v7.widget.RecyclerView
    android:id="@+id/card_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp"
    />



 </FrameLayout>

Answer 1

要支持它，您需要在支持CardView中指定app:cardUseCompatPadding="true"。

<android.support.v7.widget.CardView
        app:cardElevation="4dp"
        app:cardUseCompatPadding="true"
        app:cardMaxElevation="6dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
</android.support.v7.widget.CardView>

Answer 2

In your code you used frame layout in recycler view item and inside that you have cardview. You gives margin as 10dp to frame layout but my suggestion to you is that remove that line and add margin to the card view. In recycler view there are no space between items so shadow of your cardview may be hidden because your outer frame layout completes there so try by cahnging your code like this :

    <?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:layout_height="wrap_content"
             android:layout_width="match_parent"
             xmlns:android="http://schemas.android.com/apk/res/android"
             xmlns:card_view="http://schemas.android.com/apk/res-auto"
             xmlns:app="http://schemas.android.com/apk/res-auto"
             android:padding="10dp">


<android.support.v7.widget.CardView
    android:id="@+id/card_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorAccent"
    app:cardUseCompatPadding="true"
    app:cardMaxElevation="6dp"
    android:layout_marginBottom="10dp"
    app:cardCornerRadius="3dp"
    app:cardElevation="24dp">

    <LinearLayout android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/thumbnail"
            android:layout_width="match_parent"
            android:layout_height="250dp" />

        <TextView
            android:id="@+id/title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/thumbnail"
            />
    </LinearLayout>


</android.support.v7.widget.CardView> 
</FrameLayout>

Answer 3

在卡片视图中使用此功能。它解决了我同样的问题。

app:cardUseCompatPadding="true"

Answer 4

将此行添加到CardView xml标记;

android:layout_margin="10dp"

Answer 5

我只是遇到了同样的问题，发现的解决方案是在AndroidManifest中添加下一个标签：

android:hardwareAccelerated="true"

示例：

<application
        android:allowBackup="true"
        android:hardwareAccelerated="true"
        android:icon="@mipmap/ic_launcher"
        android:theme="@style/AppTheme">

文档：

https://developer.android.com/guide/topics/graphics/hardware-accel

Answer 6

这是下面的屏幕截图的xml示例代码：

<androidx.cardview.widget.CardView 
    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="wrap_content"
    app:cardCornerRadius="10dp"
    app:cardElevation="2dp"
    app:cardPreventCornerOverlap="true"
    app:cardUseCompatPadding="true"
    app:contentPadding="10dp"
    app:contentPaddingBottom="0dp">

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

        <TextView
            android:id="@+id/name_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Name" />
        <TextView
            android:id="@+id/sim_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="SIM" />
        <TextView
            android:id="@+id/ID_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="ID" />
        <TextView
            android:id="@+id/model_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="model" />
    </LinearLayout>

</androidx.cardview.widget.CardView>