扩展类和android.support.v7.widget.CardView时出错

Question

我想在我的项目中使用CardView,但是当我运行我的应用程序时,我收到以下错误.我正在使用Eclipse.

Error: Error inflating class and android.support.v7.widget.CardView

The graphical view of my xml file says 'The following classes could not be instantiated:
- android.support.v7.widget.CardView (Open Class, Show Error Log)
See the Error Log (Window > Show View) for more details.'

请帮忙.

这是我使用过的片段的布局 CardView

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.log.MyContactsFragment" >

<!-- TODO: Update blank fragment layout -->

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/cvContactDetails"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:layout_gravity="center"
    android:background="?android:attr/selectableItemBackground"
    android:clickable="false"
    android:elevation="20dp" >

    <TextView
        android:id="@+id/tvContacts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Contact Info" />

    <Button
        android:id="@+id/bDelete"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Delete" />

    <Button
        android:id="@+id/bExport"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Export to phone contacts" />
</android.support.v7.widget.CardView>

这是我活动的布局.

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <FrameLayout
        android:id="@+id/flMainContent"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </FrameLayout>

    <ListView
        android:id="@+id/lvLeftDrawer"
        android:layout_width="200dp"
        android:layout_height="match_parent"
        android:layout_gravity="left"
        android:alpha="255"
        android:background="#0B2161"
        android:divider="@null"
        android:choiceMode="singleChoice" >
    </ListView>

    <ListView
        android:id="@+id/lvRightDrawer"
        android:layout_width="200dp"
        android:layout_height="match_parent"
        android:layout_gravity="right"
        android:alpha="255"
        android:background="#0B2161"
        android:divider="@null"
        android:choiceMode="singleChoice" >
    </ListView>

</android.support.v4.widget.DrawerLayout>

这是我的logcat

FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.log/com.example.log.HomeScreenActivity}: android.view.InflateException: Binary XML file line #9: Error inflating class android.support.v7.widget.CardView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #9: Error inflating class android.support.v7.widget.CardView
at android.view.LayoutInflater.createView(LayoutInflater.java:613)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
at com.example.log.MyContactsFragment.onCreateView(MyContactsFragment.java:60)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1504)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:942)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1121)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1484)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:571)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1163)
at android.app.Activity.performStart(Activity.java:5018)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2032)
... 11 more
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Constructor.constructNative(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
at android.view.LayoutInflater.createView(LayoutInflater.java:587)
25 more
Caused by: java.lang.NoClassDefFoundError: android.support.v7.cardview.R$styleable
at android.support.v7.widget.CardView.initialize(CardView.java:203)
at android.support.v7.widget.CardView.<init>(CardView.java:101)
... 28 more

遇到同样问题或解决问题的人请评论.

Answer 1

我想我可以回答我自己的问题.

转到文件 - >导入 - >现有Android代码到工作区 - >浏览(转到sdk/extras/android/support/v7/cardview) - >单击确定 - >单击完成

您的项目资源管理器现在将cardview显示为项目.

右键单击cardview项目 - >属性 - > Android(左窗格) - >启用isLibrary(勾选复选框) - >应用 - >确定

现在右键单击你的项目 - >属性 - > Android(左窗格) - >添加(在库下) - > cardview - > apply - > ok

现在再次右键单击您的项目 - >构建路径 - >配置构建路径 - >在项目选项卡下,添加cardview

你完成了.

Answer 2

我猜您的问题不在您的xml布局中,而是您的build.gradle设置.

如果要在较低API设备中使用Recyclerview或CardView的支持库,则不仅需要导入v7库,还需要单独导入Recycler View和Card View支持.

像这样:

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.+'
    compile 'com.android.support:cardview-v7:21.0.+'
    compile 'com.android.support:recyclerview-v7:21.0.+'
    compile 'com.android.support:support-v4:21.0.0'
} 

Google的文档在此处注明:https://developer.android.com/training/material/compatibility.html

请参阅依赖项部分.

此外,您可以下载谷歌的RecyclerView样本进行挖掘.

希望这会有所帮助!

Answer 3

在我的情况下,我必须做两件事添加android.support.v7.widget.CardView为库项目,并添加+检查它的jar文件java build path

1. 转到文件 - >导入 - >现有Android代码到工作区 - >浏览(转到sdk/extras/android/support/v7/cardview) - >单击确定 - >单击完成

2. 右键单击cardview项目 - >属性 - > Android(左窗格) - >启用isLibrary(勾选复选框) - >应用 - >确定

3. 右键单击你的项目 - >属性 - > Android(左窗格) - >添加(在库下) - > cardview - > apply - > ok

4. 再次右键单击您的项目 - >构建路径 - >配置构建路径 - >库下 - >添加jar - >展开cardview - >展开库 - >选择 android.support.v7.widget.CardView.jar

5. 在订单和导出 - >检查android.support.v7.widget.CardView.jar- >单击确定