java.lang.NullPointerException:缺少 ID 所需的视图: [英] java.lang.NullPointerException: Missing required view with ID:
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问题描述
Android Studio 3.6
Android Studio 3.6
在 app/build.gradle 中:
in app/build.gradle:
android {
viewBinding.enabled = true
这里是我的 xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/bluetoothBottonMainContainer"
android:layout_width="0dp"
android:layout_height="104dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<View
android:id="@+id/viewPointNotSelect"
android:layout_width="16dp"
android:layout_height="16dp"
android:background="@drawable/circle_transparent"
app:layout_constraintBottom_toBottomOf="@+id/separator"
app:layout_constraintEnd_toStartOf="@+id/separator"
app:layout_constraintTop_toTopOf="parent" />
和另一个 xml unclude prev.xml:
and another xml the unclude prev. xml:
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/bottonContainer"
android:layout_width="0dp"
android:layout_height="104dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<include
android:id="@+id/qrBottonContainer"
layout="@layout/qr_bottom_container"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
这里是我的活动:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = QrBluetoothSwipeActivityBinding.inflate(layoutInflater)
setContentView(binding.root)
}
应用程序已构建并运行.不错.
the app is build and run. Nice.
现在我移动 id - android:id="@+id/bluetoothBottonMainContainer"
Now I move id - android:id="@+id/bluetoothBottonMainContainer"
像这样的外部容器:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/bluetoothBottonMainContainer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="0dp"
android:layout_height="104dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<View
android:id="@+id/viewPointNotSelect"
android:layout_width="16dp"
android:layout_height="16dp"
android:background="@drawable/circle_transparent"
app:layout_constraintBottom_toBottomOf="@+id/separator"
app:layout_constraintEnd_toStartOf="@+id/separator"
app:layout_constraintTop_toTopOf="parent" />
app 正在构建，但是在运行时我在这一行出现运行时错误:
app is build, but when run I get runtime error in this line:
binding = QrBluetoothSwipeActivityBinding.inflate(layoutInflater)
错误:
10-25 11:11:51.290 E/AndroidRuntime(14128): FATAL EXCEPTION: main
10-25 11:11:51.290 E/AndroidRuntime(14128): Process: com.myproject.debug, PID: 14128
10-25 11:11:51.290 E/AndroidRuntime(14128): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myproject.debug/com.myproject.ui.actviity.QRBluetoothSwipeActivity}: java.lang.NullPointerException: Missing required view with ID: bluetoothBottonMainContainer
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread.-wrap11(ActivityThread.java)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.os.Handler.dispatchMessage(Handler.java:102)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.os.Looper.loop(Looper.java:148)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread.main(ActivityThread.java:5417)
10-25 11:11:51.290 E/AndroidRuntime(14128): at java.lang.reflect.Method.invoke(Native Method)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
10-25 11:11:51.290 E/AndroidRuntime(14128): Caused by: java.lang.NullPointerException: Missing required view with ID: bluetoothBottonMainContainer
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.myproject.databinding.BluetoothBottomContainerBinding.bind(BluetoothBottomContainerBinding.java:114)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.myproject.databinding.QrBluetoothSwipeActivityBinding.bind(QrBluetoothSwipeActivityBinding.java:76)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.myproject.databinding.QrBluetoothSwipeActivityBinding.inflate(QrBluetoothSwipeActivityBinding.java:62)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.myproject.databinding.QrBluetoothSwipeActivityBinding.inflate(QrBluetoothSwipeActivityBinding.java:52)
10-25 11:11:51.290 E/AndroidRuntime(14128): at com.myproject.ui.actviity.QRBluetoothSwipeActivity.onCreate(QRBluetoothSwipeActivity.kt:31)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.Activity.performCreate(Activity.java:6251)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
10-25 11:11:51.290 E/AndroidRuntime(14128): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
10-25 11:11:51.290 E/AndroidRuntime(14128): ... 9 more
10-25 11:11:51.291 W/ActivityManager( 780): Force finishing activity com.myproject.debug/com.myproject.ui.actviity.QRBluetoothSwipeActivity
10-25 11:11:51.307 I/Icing (11529): Indexing done com.google.android.gms-apps
推荐答案
我遇到了这个问题，但就我而言，问题是 include 标志.我找到的解决方法是使视图 id 与包含的布局的根视图的 id 相同.
I encountered this issue but in my case the issue is the include flag. The workaround I found is to make the view id to be the same as the id of the root view of the included layout.
activity_layout.xml
<LinearLayout>
<include android:id="@+id/widget1" layout="@layout/my_widget" />
</LinearLayout>
my_widget.xml
<LinearLayout
android:id="@+id/widget1">
</LinearLayout>
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