java - Android Studio下面的类无法实例化？

Question

我收到错误 android.support.v7.widget.Toolbar in Eclipse could not be instantiated我正在按照教程 here 开发 Android Studio 1.2.1.1我尝试了在 Google 和 Stackoverflow 上搜索的不同帮助页面中的一些提示，但没有一个对我有用。首先我将 android 版本切换到 22 但仍然出现错误。请注意，当使用版本 22 时，我扩展了类 AppCombatActivity这是我使用版本 22 时的异常详细信息。

java.lang.ClassNotFoundException: android.support.v7.appcompat.R$attr
at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:127)
at com.android.tools.idea.rendering.RenderClassLoader.findClass(RenderClassLoader.java:53)
at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:84)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at android.support.v7.widget.Toolbar.<init>(Toolbar.java:192)
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.rInflate_Original(LayoutInflater.java:809)
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)

当我将 Android 版本设置为 21 时，我收到相同的错误，并且又收到一个错误，其中 android.support.v7.widget.RecyclerView in Eclipse could not be instantiated

java.lang.UnsupportedOperationException: Unsupported Service: accessibility
at com.android.layoutlib.bridge.android.BridgeContext.getSystemService(BridgeContext.java:463)
at android.support.v7.widget.RecyclerView.<init>(RecyclerView.java:302)
at android.support.v7.widget.RecyclerView.<init>(RecyclerView.java:278)
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:207)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:132)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:806)
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:400)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:332)
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)

我还使缓存无效并重新启动了我的 Android Studio。我也尝试过扩展类 Activity 但仍然存在相同的错误。

这是我的主要 Activity XML

<?xml version="1.0" encoding="utf-8"?>

xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/DrawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:elevation="7dp">


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <include
        android:id="@+id/tool_bar"
        layout="@layout/tool_bar">
    </include>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World" />

</LinearLayout>


<android.support.v7.widget.RecyclerView
    android:id="@+id/RecyclerView"
    android:layout_width="320dp"
    android:layout_height="match_parent"
    android:layout_gravity="left"

    android:background="#ffffff"
    android:scrollbars="vertical">

</android.support.v7.widget.RecyclerView>

这是我的tool_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/ColorPrimary"
    android:elevation="4dp"

    >

</android.support.v7.widget.Toolbar>

这是我的 Gradle 文件

dependencies {
  compile fileTree(include: ['*.jar'], dir: 'libs')
  compile 'com.android.support:appcompat-v7:22.1.1'
  compile 'de.hdodenhof:circleimageview:1.2.1'
  compile 'com.android.support:recyclerview-v7:21.0.+'
}

所有其他文件与教程中的文件相同，除了我删除了 <span></span>元素。我该如何修复这个错误？

Answer 1

您必须在 Gradle 文件中添加依赖项。

dependencies { 

    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.1.1'
    compile 'com.android.support:recyclerview-v7:21.0.+'
}

并重建您的项目。