android Unable to inflate view tag without class attribute-优快云博客

本文链接：https://blog.youkuaiyun.com/chaoxionghuai/article/details/68944129

本文记录了一次在Android开发过程中遇到的布局文件错误问题及解决方法。错误表现为启动Activity时报NullPointerException，通过排查发现是布局文件中<view>标签未使用正确的大小写导致。

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今天写一 tv 项目布局文件，运行报错

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.droid/com.droid.activitys.UserCenterActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1306)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5274)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:955)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:750)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:715)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:809)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
at android.app.Activity.setContentView(Activity.java:2160)

定位到问题是布局文件出错， Unable to inflate view tag without class attribute

错误原因

<view
    android:layout_width="match_parent"
    android:layout_height="2dp"
    android:background="@color/white"/>

分割线处错误。<view ... 改为

<View
    android:layout_width="match_parent"
    android:layout_height="2dp"
    android:background="@color/white"/>

大写的 <View ...

手误错误真可怕。。。