我们最近将公司的Android Studio网站版本升级到2.3.3，每当我们尝试预览布局时，我们都会在xml预览器中遇到以下错误。
The following classes could not be instantiated:
- android.support.v7.widget.AppCompatTextView
java.lang.NullPointerException
at android.content.res.Resources_Delegate.getValue(Resources_Delegate.java:788)
at android.content.res.Resources.getValue(Resources.java:1286)
at android.support.v4.content.res.ResourcesCompat.loadFont(ResourcesCompat.java:212)
at android.support.v4.content.res.ResourcesCompat.getFont(ResourcesCompat.java:206)
at android.support.v7.widget.TintTypedArray.getFont(TintTypedArray.java:119)
at android.support.v7.widget.AppCompatTextHelper.updateTypefaceAndStyle(AppCompatTextHelper.java:208)
at android.support.v7.widget.AppCompatTextHelper.loadFromAttributes(AppCompatTextHelper.java:152)
at android.support.v7.widget.AppCompatTextHelperV17.loadFromAttributes(AppCompatTextHelperV17.java:38)
at android.support.v7.widget.AppCompatTextView.<init>(AppCompatTextView.java:81)
at android.support.v7.widget.AppCompatTextView.<init>(AppCompatTextView.java:71)
at sun.reflect.GeneratedConstructorAccessor153.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:475)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:250)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:213)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadClass(LayoutlibCallbackImpl.java:193)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:333)
at android.view.BridgeInflater.onCreateView(BridgeInflater.java:152)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:222)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:858)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:834)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at com.android.layoutlib.bridge.bars.CustomBar.<init>(CustomBar.java:95)
at com.android.layoutlib.bridge.bars.StatusBar.<init>(StatusBar.java:67)
at com.android.layoutlib.bridge.impl.Layout.createStatusBar(Layout.java:224)
at com.android.layoutlib.bridge.impl.Layout.<init>(Layout.java:146)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:301)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:429)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:368)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:567)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:549)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:863)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:549)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$1(RenderTask.java:680)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
我们在这个特定的例子中使用了支持库26.0.0。
这不影响预览仍然生成的布局渲染，但是它让我们的开发人员感到烦恼，因为它似乎可以防止特定错误被正确显示。
答案 0 :(得分：0)
目前临时修复可能是针对API级别25（如果可能），直到Google发布API 26的稳定版本。当然，这不是最佳选择，但如果你的目标是API lvl 25（appcompat- v7：25.3.1）错误消失。