使用Material Button会产生ClassNotFound运行时错误

Question

我正在使用<com.google.android.material.button.MaterialButtonXML文件和private MaterialButton dateButton;Java片段文件中的Material Buttons替换我的应用程序中的按钮.我研究了代码实验室" MDC-101 Android:Material Components(MDC)Basics(Java) "以了解如何使用Material Button.在gradle.build(Module:app)文件中,我添加了代码实验室中的依赖项.代码实验室编译并运行良好.我的应用程序编译正常,但在膨胀片段布局时出错:

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)

这是我的布局文件的片段:

<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>

这是onCreateView的一个片段:

@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);

我只将datebutton更改为Material Button,这给了我错误.使用日常按钮作为dateButton时,应用程序运行正常.

这是我的gradle.build文件:

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'

其中$ rootProject.supportVersion是28.0.0-beta01.我知道某些库的rc-01和rc02可用,但是我运行了带有beta01依赖关系的代码实验室,因此决定保留此版本以尽量减少更改.

有谁知道导致运行时错误的原因是什么？

Answer 1

因为它建议在这里你必须在build.gradle中添加一个依赖项:

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

或者,如果您已经使用Google支持设计库,则必须更改您的应用主题以继承Material Components主题

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

如果您无法将主题更改为从Material Components主题继承,则可以从Material Components Bridge主题继承.

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

雷斯克如何说:

请注意,它现在已经过时了!所以你可以使用实现'com.google.android.material:material:1.0.0'

Answer 2

在我看来，最好的选择是为材料按钮创建一个单独的自己的样式，它扩展了材料主题：

<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"
    />

Answer 3

崩溃时以下消息输出到Logcat.

引发者:java.lang.IllegalArgumentException:此组件要求您指定有效的TextAppearance属性.更新您的应用主题以继承Theme.MaterialComponents(或后代).

因此,您还可以通过添加TextAppearance来显示MaterialButton.

<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" />

Answer 4

如果你在你的应用中使用 Material 主题组件，那么试试这个。

从之前到之后更改你的styles.xml ->

前：

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>
</resources>

后：

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>
</resources>