最近我在android studio中的应用程序中将我的sdk从25改为26，我在我的所有xml中都遇到了这个奇怪的错误。目前错误并没有以我能看到的任何方式影响我的应用程序，但是每次我必须编辑或更改xml中的内容时都很烦人。 错误在这里：
无法实例化以下类 - 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.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.<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)
我的朋友们：
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
buildToolsVersion "26.0.1"
defaultConfig {
applicationId "com.al285790.time2cook"
minSdkVersion 15
targetSdkVersion 26
multiDexEnabled true
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:26.0.1'
compile 'com.android.support:palette-v7:26.0.1'
compile 'com.android.support:design:26.0.1'
compile 'com.google.firebase:firebase-database:11.0.2'
compile 'com.google.firebase:firebase-core:9.6.1'
compile 'com.google.firebase:firebase-storage:11.0.2'
compile 'com.google.firebase:firebase-auth:11.0.2'
compile 'com.github.bumptech.glide:glide:3.7.0'
compile 'com.firebaseui:firebase-ui-storage:1.2.0'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
compile('com.mikepenz:materialdrawer:5.9.5@aar') {
transitive = true
}
testCompile 'junit:junit:4.12'
}
apply plugin: 'com.google.gms.google-services'
编辑：添加了一些我的xml代码
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"></android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="android.support.design.widget.AppBarLayout$ScrollingViewBehavior">
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.al285790.time2cook.recipeInfo.RecipeInfoActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:scrollbars="none">
<TextView
android:id="@+id/recipeNameText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="24sp"
android:textStyle="bold" />
<ImageView
android:id="@+id/photoRecipe"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scaleType="fitCenter"
app:srcCompat="@drawable/cho" />
<TextView
android:id="@+id/textView10"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Dificulty"
android:textSize="24sp"
android:textStyle="bold" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<RatingBar
android:id="@+id/ratingBarDificulty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:isIndicator="true"
android:numStars="5"
android:stepSize="1" />
<Button
android:id="@+id/button8"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="giveLike"
android:text="LIKE!" />
</LinearLayout>
<TextView
android:id="@+id/Ingredients"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Ingredients"
android:textSize="24sp"
android:textStyle="bold" />
<android.support.v7.widget.RecyclerView
android:id="@+id/superList"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/textView9"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Steps"
android:textSize="24sp"
android:textStyle="bold" />
<android.support.v7.widget.RecyclerView
android:id="@+id/stepsList"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
答案 0 :(得分：26)
我也遇到了这个错误，并尝试通过多次清理，重建和使缓存无效来修复它。
修正它的原因是将res/values/styles.xml中的父主题更改为Base的父主题，例如
<style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
根据答案here。
答案 1 :(得分：0)
你可以尝试两件事：
清洁/重建
打开Android Studio并转到工具 - ＆gt;清理项目并让gradle构建运行。
完成后，转到工具 - ＆gt;重建项目。
使缓存无效
答案 2 :(得分：0)
它是Android Studio 2.3.3中的一个错误，已被报道 - Preview render problem when adding maven.google.com as a maven repo
不幸的是，这个错误在Android Studio 2.3.3中无法修复，但已在Android Studio 3.0中得到修复
因此，让我们等到Android Studio 3.0的稳定版本
Android Studio 3.0现在处于稳定的渠道。更新它，你不会看到这个错误