java - CardView 在运行时不显示高程

Question

这是xml代码:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/activity_main"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.himanshu.staticlogin.MainActivity"
android:weightSum="1">
<android.support.v7.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    card_view:cardBackgroundColor="@color/cardview_dark_background"
    card_view:cardElevation="10dp"
    android:clickable="true"
    />
</LinearLayout>

它在预览中显示了高度，但当我运行该文件时却没有。我做错了什么？

Answer 1

设置卡片 View :

card_view:cardUseCompatPadding="true"