Question

我正在尝试在我的应用中使用工具栏。我过去做过这个没有问题。在我尝试使用此工具栏的布局中，我收到错误：

java.lang.NoClassDefFoundError: android/support/v7/appcompat/R$attr
at android.support.v7.widget.Toolbar.<init>(Toolbar.java:191)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:413)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:105)
at com.android.tools.idea.rendering.LayoutlibCallback.loadView(LayoutlibCallback.java:177)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:214)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:142)
at android.view.LayoutInflater_Delegate.parseInclude(LayoutInflater_Delegate.java:117)
at android.view.LayoutInflater.parseInclude(LayoutInflater.java:858)
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:782)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:385)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:413)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:321)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:497)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:485)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:894)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:485)
at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:590)
at com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$6.run(AndroidDesignerEditorPanel.java:480)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310)
at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227)
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

在“Toolbar.java”中，import android.support.v7.appcompat.R;语句失败 - 它显示为cannot resolve symbol 'R'。

我试过清理项目，我尝试重建项目，我的build.gradle文件中有正确的'compile'依赖项，我试过'File＆gt;无效缓存/重启'我不知道问题是什么。这是我的build.gradle文件：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "me.bausware.set"
        minSdkVersion 15
        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:appcompat-v7:22.2.0'
}

Answer 1

检查您在styles.xml中设置的主题。当您使用新的AppCompat Toolbar时，您应该将主题更改为继承其中一个AppCompat主题，例如：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="MyAppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:colorPrimary">@color/primary</item>
        <item name="android:colorPrimaryDark">@color/primary_dark</item>
        <item name="android:colorAccent">@color/accent</item>
    </style>
</resources>

您可以在Android Developers Blog上详细了解如何使用AppCompat Toolbar。

无法在Android Studio中导入android.support.v7.appcompat.R

1 个答案: