Android无法实例化一个或多个类

我有一个正在运行的项目,所有的xml文件都显示错误消息Android Failed to instantiate one or more classes 。 该计划仍然有效。

我清理了缓存并使用了无效的缓存和重启。

这里是完整的消息:

以下类无法实例化android.support.v7.widget.AppCompatTextView

提示:在IDE中显示时,在自定义视图中使用View.isInEditMode()可跳过代码或显示示例数据。

 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.(AppCompatTextView.java:81) at android.support.v7.widget.AppCompatTextView.(AppCompatTextView.java:71) 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: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.(CustomBar.java:95) at com.android.layoutlib.bridge.bars.StatusBar.(StatusBar.java:67) at com.android.layoutlib.bridge.impl.Layout.createStatusBar(Layout.java:224) at com.android.layoutlib.bridge.impl.Layout.(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) 

styles.xml

将主题从Theme.AppCompat.Light.DarkActionBar更改为Base.Theme.AppCompat.Light.DarkActionBar对我Base.Theme.AppCompat.Light.DarkActionBar

最后,在面对同样的错误4天后,我自己解决了这个问题:

点击

构建 – >构建

接着

刷新布局。

build.gradle (Module: app )中,通过搜索developer.googleappcompat的实现更改为以前的版本

这是android框架中的一个错误,通常发生在alpha和beta appcompat版本中。

希望这可以帮助。