android – Using Material Button gives ClassNotFound runtime error-ThrowExceptions

Exception or error:

I am in the process of replacing the buttons in my app with Material Buttons using <com.google.android.material.button.MaterialButton in the XML file and private MaterialButton dateButton; in the Java fragment file.
I studied the Code Lab “MDC-101 Android: Material Components (MDC) Basics (Java)” to see how a Material Button is used. In the gradle.build (Module:app) file I added the dependencies like in the code lab.
The code lab compiles and runs fine. My app compiles fine but gives an error when inflating the fragment layout:

E/AndroidRuntime: FATAL EXCEPTION: main
              Process: nl.kl_solutions.schedulecompareforzermelo, PID: 16708
              android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class com.google.android.material.button.MaterialButton
              Caused by: android.view.InflateException: Binary XML file line #26: Error inflating class com.google.android.material.button.MaterialButton
              Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.android.material.button.MaterialButton" on path: DexPathList[[zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/base.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_dependencies_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_resources_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_0_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_1_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_2_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_3_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_4_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_5_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_6_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_7_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_8_apk.apk", zip file "/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/data/app/nl.kl_solutions.schedulecompareforzermelo-o6fuvqQPirym08EhaTRI6Q==/lib/x86_64, /system/lib64]]
                  at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:134)

This is a snippet from my layout file:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:background="@color/primaryLightColor"
    android:paddingLeft="@dimen/rasterleftpadding"
    android:paddingRight="@dimen/rasterrightpadding" >

    <Button
        android:id="@+id/btn_previous"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:layout_gravity="left"
        android:text="prev" />

    <com.google.android.material.button.MaterialButton
        android:id="@+id/btn_week"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_weight="1"
         />

    <Button
        android:id="@+id/btn_next"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right"
        android:layout_weight="1"
        android:text="next" />

</LinearLayout>

And here is a snippet from the onCreateView:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View fragmentLayout = inflater.inflate(R.layout.fragment_week_schedule, container, false);
    //get references to the buttonBar buttons.
    leftButton = fragmentLayout.findViewById(R.id.btn_previous);
    rightButton = fragmentLayout.findViewById(R.id.btn_next);
    dateButton = fragmentLayout.findViewById(R.id.btn_week);

I only changed the datebutton to a Material Button which gives me the error. The app runs fine when using an ordinary Button for the dateButton.

This is my gradle.build file:

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "com.android.support:appcompat-v7:$rootProject.supportVersion"
implementation "com.android.support:preference-v7:$rootProject.supportVersion"
implementation "com.android.support:recyclerview-v7:$rootProject.supportVersion"
implementation "com.android.support:cardview-v7:$rootProject.supportVersion"
implementation "com.android.support.constraint:constraint-layout:1.1.3"
implementation "com.android.support:design:$rootProject.supportVersion"
implementation "com.android.support:support-v4:$rootProject.supportVersion"
implementation 'com.google.code.gson:gson:2.8.5'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

//database components
implementation "android.arch.persistence.room:runtime:$rootProject.roomVersion"
annotationProcessor "android.arch.persistence.room:compiler:$rootProject.roomVersion"

// Lifecycle components
implementation "android.arch.lifecycle:extensions:$rootProject.archLifecycleVersion"
annotationProcessor "android.arch.lifecycle:compiler:$rootProject.archLifecycleVersion"
//QR library
implementation 'me.dm7.barcodescanner:zxing:1.9.8'

where $rootProject.supportVersion is 28.0.0-beta01. I know that rc-01 and rc02 for some libraries are available but I ran the code lab with the beta01 dependencies so decided to keep this version to minimize changes.

Anybody knows what is causing the runtime error?

How to solve:

As it suggest HERE you have to add a dependency in your build.gradle:

implementation 'com.google.android.material:material:1.0.0-beta01'

Or if you already use google support design library you must change your app theme to inherit from a Material Components theme

<style name="Theme.MyApp" parent="Theme.MaterialComponents.Light">
<!-- ... -->

If you cannot change your theme to inherit from a Material Components theme, you can inherit from a Material Components Bridge theme.

<style name="Theme.MyApp" parent="Theme.MaterialComponents.Light.Bridge">
<!-- ... -->

How Reyske said:

note that it is out of beta now! So you can use implementation 'com.google.android.material:material:1.0.0'

###

When crashing The following message was output to Logcat.

Caused by: java.lang.IllegalArgumentException: This component requires that you specify a valid TextAppearance attribute. Update your app theme to inherit from Theme.MaterialComponents (or a descendant).

Therefore, you can also display MaterialButton by adding TextAppearance.

<com.google.android.material.button.MaterialButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@android:string/ok"
    android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

###

In my opinion, the best choice is to create a separate own style to the material button where it extends the material theme:

<style name="MatButton" parent="Theme.MaterialComponents">
    <item name="colorOnPrimary">@android:color/holo_red_light</item>
    <item name="colorPrimary">@android:color/holo_orange_dark</item>
    <item name="colorOnSurface">@android:color/holo_orange_light</item>
</style>

<com.google.android.material.button.MaterialButton
    android:id="@+id/searchBtn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Search"
    android:textColor="@android:color/white"
    android:textAppearance="@style/TextAppearance.MaterialComponents.Button"
    android:theme="@style/MatButton"
    />

###

Try to update your app theme to inherit from Theme.MaterialComponents (or a descendant)

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