Android 将 CardView 添加到布局时出错
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Error when adding CardView to layout
提问by trickedoutdavid
I wanted to try out the new toys that google gave us and I've run into some trouble.
我想尝试谷歌给我们的新玩具，但遇到了一些麻烦。
Here is my build.gradle:
这是我的 build.gradle：
apply plugin: 'com.android.application'
android {
compileSdkVersion 'android-L'
buildToolsVersion "20.0.0"
defaultConfig {
applicationId "com.tod.android.lpreviewtest"
minSdkVersion 'L'
targetSdkVersion 'L'
versionCode 1
versionName "1.0"
}
buildTypes {
release {
runProguard false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:cardview-v7:+'
}
Now my layout:
现在我的布局：
<RelativeLayout 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"
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=".MyActivity">
<android.support.v7.widget.CardView
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_gravity="center"
android:layout_width="200dp"
android:layout_height="200dp"
card_view:cardCornerRadius="4dp">
<TextView
android:id="@+id/info_text"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.v7.widget.CardView>
</RelativeLayout>
When I switch to screen preview in android studio, I get a render error:
当我在 android studio 中切换到屏幕预览时，出现渲染错误：
Rendering Problems The following classes could not be instantiated:
-?android.support.v7.widget.CardView (Open Class, Show Exception)
Exception Details java.lang.ClassFormatError: Illegal field name "CardView.Dark"
in class android/support/v7/cardview/R$style at
java.lang.ClassLoader.defineClass1(ClassLoader.java:-2) ??at
java.lang.ClassLoader.defineClass(ClassLoader.java:792) ??at
java.lang.ClassLoader.defineClass(ClassLoader.java:635) ??at
java.lang.ClassLoader.loadClass(ClassLoader.java:424) ??at
java.lang.ClassLoader.loadClass(ClassLoader.java:411) ??at
java.lang.ClassLoader.loadClass(ClassLoader.java:357) ??at
android.support.v7.widget.CardView.initialize(CardView.java:69) ??at
android.support.v7.widget.CardView.<init>(CardView.java:60) ??at
java.lang.reflect.Constructor.newInstance(Constructor.java:526) ??at
android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:802) ??at
android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:64) ??at
android.view.LayoutInflater.rInflate(LayoutInflater.java:778) ??at
android.view.LayoutInflater.inflate(LayoutInflater.java:500) ??at
android.view.LayoutInflater.inflate(LayoutInflater.java:381)
I tried ignoring the error and running the app in an avd and while everything compiles fine, no cardview appears in the layout. Please help!
我尝试忽略错误并在 avd 中运行应用程序，虽然一切都编译正常，但布局中没有出现 cardview。请帮忙！
P.s. I'm using the new Android Studio beta 0.8.0
Ps 我正在使用新的 Android Studio beta 0.8.0
采纳答案by personne3000
This is a bug in Android Studio, see https://code.google.com/p/android/issues/detail?id=79071
这是 Android Studio 中的一个错误，请参阅https://code.google.com/p/android/issues/detail?id=79071
One of the comments of the patch reads: "This was causing card view rendering to fail. CardView declared styles of the form CardView.Dark due to which the generated R class failed to load."
该补丁的评论之一是：“这导致卡片视图渲染失败。CardView 声明了 CardView.Dark 形式的样式，因此生成的 R 类无法加载。”
Next version should have this fixed according to the bug report (the patch is on branch studio-1.0-dev). They say to build the project once as a workaround, but this does not fix it for me (even though I have exactly the same error and stack trace).
下一个版本应该根据错误报告修复这个问题（补丁在分支 studio-1.0-dev 上）。他们说将项目构建一次作为解决方法，但这并不能解决我的问题（即使我有完全相同的错误和堆栈跟踪）。
回答by
I was able to get it to work on the emulator by changing my build.gradle to this:
通过将我的 build.gradle 更改为以下内容，我能够让它在模拟器上运行：
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:cardview-v7:+'
}
Make sure you have the support repository installed from the SDK Manager! Hope this helps
确保您已从 SDK Manager 安装了支持存储库！希望这可以帮助
EDIT: as someone suggested using 'com.android.support:cardview-v7:23.1' is a better practice but it not required.
编辑：正如有人建议使用 'com.android.support:cardview-v7:23.1' 是更好的做法，但不是必需的。
回答by Bubunyo Nyavor
try adding this line to your RelativeLayout
尝试将此行添加到您的 RelativeLayout
xmlns:card_view="http://schemas.android.com/apk/res-auto"
回答by Sathish Kumar
It solved me by adding xmlns:card_view="http://schemas.android.com/apk/res-auto"
它通过添加解决了我 xmlns:card_view="http://schemas.android.com/apk/res-auto"
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:card_view="http://schemas.android.com/apk/res-auto"> --->> ******
....
...
<android.support.v7.widget.CardView>
..
...
.....
</android.support.v7.widget.CardView>
</LinearLayout>
回答by user3845801
I was able to get this to work by adding the following to my build.gradle: compile 'com.android.support:cardview-v7:21.+'
我能够通过将以下内容添加到我的 build.gradle 来使其工作：compile 'com.android.support:cardview-v7:21.+'
Hope this helps.
希望这可以帮助。
回答by Williams Tobi
Try adding this to your build.gradle file
尝试将其添加到您的 build.gradle 文件中
dependencies {
...
compile 'com.android.support:cardview-v7:21.0.+'
compile 'com.android.support:recyclerview-v7:21.0.+'
...
}
回答by Kunal kumawat
Go to app, right click on: Open module -> Settings -> Dependencies.
转到应用程序，右键单击：打开模块 -> 设置 -> 依赖项。
Go to "Declared dependencies" and you will find the "+" sign under the title.
转到“声明的依赖项”，您会在标题下找到“+”号。
Click on "Library dependencies".
单击“库依赖项”。
Search for "Material" and go to "version section".
搜索“材料”并转到“版本部分”。
Apply 1.0.0 and click "ok".
应用 1.0.0 并单击“确定”。
And then search for card view you will get it on and the class
然后搜索卡片视图，您将获得它和课程
