android.support.v7.widget.cardview cannot be found

Question

I'm using Android Studio 1.2.2 and attempting to use the CardView in my layout, but the preview is giving me the warning that the class android.support.v7.widget.CardView could not be found. This question has been asked various times, and I have looked at these solutions:

Error when adding CardView to layout

android.support.v7.widget.CardView could not be found (Android Studio 1.1 Preview)

But none of them have the answer. I have added this to my gradle:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:cardview-v7:21.0.+'
}

and I have added this to the layout:

xmlns:card_view="http://schemas.android.com/apk/res-auto"

which pretty much sums up the answers given on the two similar questions asked, but I am still getting the same error, and when I run it on a device, the CardView doesn't show up at all. Can anyone point out any other possible solutions?

By the way, the minSdkVersion is 21.

Layout:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent"
android:layout_height="match_parent" 
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" 
tools:context="integraloftan.cardview.main">

<android.support.v7.widget.CardView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:elevation="100dp"
    card_view:cardCornerRadius="8dp">
</android.support.v7.widget.CardView>

and gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "21.1.2"

    defaultConfig {
        applicationId "integraloftan.match"
        minSdkVersion 21
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:cardview-v7:22.2.0'
}

What is your `buildToolsVersion` (you can see it in the `build.gradle` file)? Also, is it important for you to use support library v21, not v22? — Mikhail, Jul 16 '15 at 20:29
"Can anyone point out any other possible solutions?" -- don't use the preview. If the XML is fine, and your code is fine, the buggy preview tool should not be a show-stopper. — CommonsWare, Jul 16 '15 at 20:34
My buildToolsVersion is 22.0.1, and the error isn't just on the preview, the CardView doesn't show up when I run it on a device or emulator. — IntegralOfTan, Jul 16 '15 at 20:36
@IntegralOfTan try setting `buildToolsVersion` to 21.1.2 *or* use support library v22.2.0 — Mikhail, Jul 16 '15 at 20:39
change `compile 'com.android.support:cardview-v7:21.0.+'` to `compile 'com.android.support:cardview-v7:22.2.0'`. — Mikhail, Jul 16 '15 at 20:45
I've tried changing the buildToolsVersion and the support library, but I'm still getting the same error. — IntegralOfTan, Jul 16 '15 at 20:48

score 0 · Accepted Answer · answered Jul 16 '15 at 21:06

0

First of all, sorry if I made it unclear: set buildToolsVersion to 22.0.1
Secondly, your CardView doesn't have any children and its height is set to wrap_content, that's probably why you don't see anything. Try setting height to a fixed value like 100dp and see if it appears.

answered Jul 16 '15 at 21:06

Mikhail

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I did both, but the cardview is still not showing up when I run it. – IntegralOfTan Jul 16 '15 at 21:12
Apologies, I was looking at the wrong activity, it works on my device. Many thanks. – IntegralOfTan Jul 16 '15 at 21:14

android.support.v7.widget.cardview cannot be found

1 Answers1