我想将一个现有的应用程序更改为使用Material Design。我将res/values/styles.xml保留如下：
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.DayNight">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
</resources>
我在res/values-v21目录下定义了一个styles.xml文件，并将Material Design主题放在里面：
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="android:Theme.Material">
<!-- Customize your theme here. -->
<item name="android:colorPrimary">@color/colorPrimary</item>
<item name="android:colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="android:colorAccent">@color/colorAccent</item>
</style>
</resources>
现在，当我尝试在Lollipop+设备上预览或运行时，设计混乱了（文本框文本未显示等）。它还在设计预览中给出了以下错误：
java.lang.NumberFormatException: Attribute '?attr/colorAccent' not found. Are you using the right theme?
at com.android.layoutlib.bridge.impl.ResourceHelper.getColor(ResourceHelper.java:76)
at android.content.res.BridgeTypedArray.getColorStateList(BridgeTypedArray.java:372)
at android.widget.TextView.<init>(TextView.java:750)
at android.widget.TextView.<init>(TextView.java:671)
at android.widget.TextView.<init>(TextView.java:667)
at sun.reflect.GeneratedConstructorAccessor115.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at android.view.LayoutInflater.createView(LayoutInflater.java:619)
at android.view.BridgeInflater.onCreateView(BridgeInflater.java:107)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:694)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:762)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:149)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:835)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:811)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:229)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:426)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:520)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:508)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:967)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:508)
at com.android.tools.idea.rendering.RenderTask.access$600(RenderTask.java:75)
at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:620)
at com.android.tools.idea.rendering.RenderTask$3.call(RenderTask.java:617)
at com.android.tools.idea.rendering.RenderService.runRenderAction(RenderService.java:371)
at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:617)
at com.android.tools.idea.rendering.RenderTask.render(RenderTask.java:639)
at com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$7.run(AndroidDesignerEditorPanel.java:519)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:337)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:327)
at com.intellij.util.ui.update.MergingUpdateQueue$3.run(MergingUpdateQueue.java:271)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:286)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:244)
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:234)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
at com.intellij.util.Alarm$Request$1.run(Alarm.java:352)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
在我的gradle文件中，我正在使用：
compileSdkVersion 23
buildToolsVersion "23.0.3"
使用：
minSdkVersion 15
targetSdkVersion 23
并且：
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.4.0'
}
我是不是忘了做什么，或者没有考虑到某些事情？谢谢。