java Android Studio：膨胀类片段时出错（加载活动\主UI时程序崩溃）

Question

我是一个初学者，在一个小项目中使用Android Studio。我已经查过这个问题，但我在解决这个问题上遇到了困难。下面是日志和代码

问题似乎与主窗体上的UI有关，我只是在尝试对某些对象或“图像”设置约束以防止它们在程序运行时四处移动后才遇到问题

代码：

    <?xml version="1.0" encoding="utf-8"?>
<安卓x.coordinatorlayout.widget.CoordinatorLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
    xmlns:app="http://schemas.安卓.com/apk/res-auto"
    xmlns:tools="http://schemas.安卓.com/tools"
    安卓:layout_width="match_parent"
    安卓:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.google.安卓.material.appbar.AppBarLayout
        安卓:layout_width="match_parent"
        安卓:layout_height="wrap_content"
        安卓:theme="@style/Theme.IAdmin.AppBarOverlay">

        <安卓x.appcompat.widget.Toolbar
            安卓:id="@+id/toolbar"
            安卓:layout_width="match_parent"
            安卓:layout_height="?attr/actionBarSize"
            安卓:background="?attr/colorPrimary"
            app:popupTheme="@style/Theme.IAdmin.PopupOverlay" />

    </com.google.安卓.material.appbar.AppBarLayout>

    <include layout="@layout/content_main" />

    <com.google.安卓.material.floatingactionbutton.FloatingActionButton
        安卓:id="@+id/fab"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_gravity="bottom|end"
        安卓:layout_margin="@dimen/fab_margin"
        app:srcCompat="@安卓:drawable/ic_dialog_email" />

</安卓x.coordinatorlayout.widget.CoordinatorLayout>

和日志（仅包括出错的地方）：

    E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.iadmin, PID: 10646
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.iadmin/com.example.iadmin.MainActivity}: 安卓.view.InflateException: Binary XML file line #23 in com.example.iadmin:layout/activity_main: Binary XML file line #18 in com.example.iadmin:layout/content_main: Error inflating class fragment
        at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
        at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at 安卓.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at 安卓.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at 安卓.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at 安卓.os.Handler.dispatchMessage(Handler.java:106)
        at 安卓.os.Looper.loop(Looper.java:223)
        at 安卓.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.安卓.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:947)
     Caused by: 安卓.view.InflateException: Binary XML file line #23 in com.example.iadmin:layout/activity_main: Binary XML file line #18 in com.example.iadmin:layout/content_main: Error inflating class fragment
     Caused by: 安卓.view.InflateException: Binary XML file line #18 in com.example.iadmin:layout/content_main: Error inflating class fragment
     Caused by: java.lang.NullPointerException: Missing required view with ID: com.example.iadmin:id/wrap_content
        at com.example.iadmin.databinding.FragmentFirstBinding.bind(FragmentFirstBinding.java:132)
        at com.example.iadmin.databinding.FragmentFirstBinding.inflate(FragmentFirstBinding.java:77)
        at com.example.iadmin.FirstFragment.onCreateView(FirstFragment.java:24)
        at 安卓x.fragment.app.Fragment.performCreateView(Fragment.java:2963)
        at 安卓x.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518)
        at 安卓x.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at 安卓x.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:112)
        at 安卓x.fragment.app.FragmentManager.moveToState(FragmentManager.java:1647)
        at 安卓x.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3128)
        at 安卓x.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3065)
        at 安卓x.fragment.app.Fragment.performViewCreated(Fragment.java:2988)
        at 安卓x.fragment.app.FragmentStateManager.ensureInflatedView(FragmentStateManager.java:392)
        at 安卓x.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:281)
        at 安卓x.fragment.app.FragmentLayoutInflaterFactory.onCreateView(FragmentLayoutInflaterFactory.java:140)
        at 安卓x.fragment.app.FragmentController.onCreateView(FragmentController.java:135)
        at 安卓x.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:319)
        at 安卓x.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:298)
        at 安卓.view.LayoutInflater.tryCreateView(LayoutInflater.java:1067)
        at 安卓.view.LayoutInflater.createViewFromTag(LayoutInflater.java:995)
        at 安卓.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
        at 安卓.view.LayoutInflater.rInflate(LayoutInflater.java:1121)
        at 安卓.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at 安卓.view.LayoutInflater.parseInclude(LayoutInflater.java:1261)
        at 安卓.view.LayoutInflater.rInflate(LayoutInflater.java:1117)
        at 安卓.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
        at 安卓.view.LayoutInflater.inflate(LayoutInflater.java:680)
        at 安卓.view.LayoutInflater.inflate(LayoutInflater.java:532)
        at com.example.iadmin.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:49)
        at com.example.iadmin.databinding.ActivityMainBinding.inflate(ActivityMainBinding.java:43)
        at com.example.iadmin.MainActivity.onCreate(MainActivity.java:30)
        at 安卓.app.Activity.performCreate(Activity.java:8000)
        at 安卓.app.Activity.performCreate(Activity.java:7984)
        at 安卓.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
        at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
        at 安卓.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at 安卓.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at 安卓.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
        at 安卓.os.Handler.dispatchMessage(Handler.java:106)
        at 安卓.os.Looper.loop(Looper.java:223)
        at 安卓.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.安卓.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:947)
W/System: A resource failed to call close. 

感谢您的帮助