cardview 不显示cornerRadius 和高程

Question

I created a card view in a recycler view and my codes work well but the problem now is that the cardview does not show the rounded edges and elevation at runtime but it shows in the design codes. my codes are shown blow

activity_main

<android.support.constraint.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=".Controller.MainActivity">

    <uk.co.markormesher.android_fab.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:buttonIcon="@drawable/ic_add_group"
        />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/groupListView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginBottom="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

my card_view.xml

<android.support.constraint.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="wrap_content">

<android.support.v7.widget.CardView
    android:id="@+id/groupCardView"
    android:layout_width="match_parent"
    android:layout_height="128dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="24dp"
    app:cardCornerRadius="10dp"
    app:cardElevation="5dp"
    app:cardUseCompatPadding="true"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent">

        <TextView
            android:id="@+id/groupTitle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:text="Trips"
            android:textAlignment="center"
            android:textSize="30sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </android.support.constraint.ConstraintLayout>
</android.support.v7.widget.CardView>

I do not know what I have done wrong

Answer 1

Anyone could encounter this issue and the solution is very simple and caused by a mistake.there's a difference between backgroundColor and cardbackgroundColor . use setcardbackgroundColor and it should work.

Answer 2

You need to set

android:background="@android:color/transparent"

for main constraint, and set

app:cardBackgroundColor="@color/white"

to cardview, np