Android &引用；java.lang.RuntimeException:无法实例化“活动”；应用程序未启动，并显示一个空白屏幕

我是android的新手。我一直在开发一个简单的应用程序。此应用程序只有一个活动。该活动包含一个按钮。单击按钮时会显示祝酒词文本

以下是我的

activity\u main.xml

文件：

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/Text_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:text="Hello World!"
        android:textSize="34sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.528"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.375" />

    <Button
        android:id="@+id/changeText_Button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_text"
        android:textSize="24sp"
        android:background="#FFC0CB"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.568"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.641" />


</androidx.constraintlayout.widget.ConstraintLayout>

当我运行应用程序时，应用程序不会加载。我显示一个空白的黑屏。 以下是日志：

=com.google.android.gms/com.google.android.location.internal.server.HardwareArProviderService }: process is bad
2020-09-14 13:57:42.606 556-580/? I/ActivityManager: Exiting empty application process 0:com.google.android.gms.persistent/u0a102 (null)
2020-09-14 13:57:42.610 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)
        at com.android.server.am.ActivityManagerService.startProcessLocked(ActivityManagerService.java:3148)
        at com.android.server.am.ActiveServices.bringUpServiceLocked(ActiveServices.java:2946)
        at com.android.server.am.ActiveServices.bindServiceLocked(ActiveServices.java:2062)
        at com.android.server.am.ActivityManagerService.bindIsolatedService(ActivityManagerService.java:15158)
        at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1833)
        at android.app.ContextImpl.bindServiceAsUser(ContextImpl.java:1783)
        at com.android.server.ServiceWatcher.rebind(ServiceWatcher.java:339)
        at com.android.server.ServiceWatcher.onBestServiceChanged(ServiceWatcher.java:310)
        at com.android.server.ServiceWatcher.onBindingDied(ServiceWatcher.java:391)
        at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1950)
        at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1986)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.os.HandlerThread.run(HandlerThread.java:67)
        at com.android.server.ServiceThread.run(ServiceThread.java:44)
2020-09-14 13:57:42.610 556-577/? I/ActivityManager: Force stopping com.google.android.gms appid=10102 user=0: start failure
2020-09-14 13:57:42.611 556-577/? I/ActivityManager:   Force stopping service ServiceRecord{946b99 u0 com.google.android.gms/com.google.android.location.network.NetworkLocationService}
2020-09-14 13:57:42.612 556-577/? W/ActivityManager: Unable to launch app com.google.android.gms/10102 for service Intent { act=com.android.location.service.v3.NetworkLocationProvider cmp=com.google.android.gms/com.google.android.location.network.NetworkLocationService }: process is bad
2020-09-14 13:57:42.613 556-580/? I/ActivityManager: Exiting empty application process 0:com.google.android.gms.persistent/u0a102 (null)
2020-09-14 13:57:42.617 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)
        at com.android.server.am.ActivityManagerService.startProcessLocked(ActivityManagerService.java:3148)
        at com.android.server.am.ActiveServices.bringUpServiceLocked(ActiveServices.java:2946)
        at com.android.server.am.ActiveServices.bindServiceLocked(ActiveServices.java:2062)
        at com.android.server.am.ActivityManagerService.bindIsolatedService(ActivityManagerService.java:15158)
        at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1833)
        at android.app.ContextImpl.bindServiceAsUser(ContextImpl.java:1783)
        at com.android.server.ServiceWatcher.rebind(ServiceWatcher.java:339)
        at com.android.server.ServiceWatcher.onBestServiceChanged(ServiceWatcher.java:310)
        at com.android.server.ServiceWatcher.onBindingDied(ServiceWatcher.java:391)
        at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1950)
        at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1986)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.os.HandlerThread.run(HandlerThread.java:67)
        at com.android.server.ServiceThread.run(ServiceThread.java:44)
2020-09-14 13:57:42.617 556-577/? I/ActivityManager: Force stopping com.google.android.gms appid=10102 user=0: start failure
2020-09-14 13:57:42.618 556-577/? I/ActivityManager:   Force stopping service ServiceRecord{d84426a u0 com.google.android.gms/com.google.android.location.fused.FusedLocationService}
2020-09-14 13:57:42.618 556-577/? W/ActivityManager: Unable to launch app com.google.android.gms/10102 for service Intent { act=com.android.location.service.FusedLocationProvider cmp=com.google.android.gms/com.google.android.location.fused.FusedLocationService }: process is bad
2020-09-14 13:57:42.622 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)

---

请帮帮我。谢谢

首先，确保您已在

manifest.xml

文件中注册了您的活动，例如：

然后，由于

activity\u main.xml

中的视图与

activity

类在

setContentView（R.layout.activity\u main）

处连接，因此在创建

Text\u textView

视图之前访问该视图就是犯了一个错误

如果需要将视图作为属性（在本例中为class scope变量），则可以遵循以下方法：

只需使用Kotlin视图扩展功能（最简单的方法）

将属性标记为延迟初始化或延迟初始化

将属性标记为可为空的类型（错误的方法）

Kotlin视图扩展功能

哪一种是最优雅的解决方案？您可以通过活动内部的id直接访问任何视图，例如，您可以使用其id

changeText\u按钮立即访问该按钮

：

//***删除***下面的行。
var text:TextView=findViewById（R.id.text\u TextView）
重写创建时的乐趣（savedInstanceState:Bundle？）{
super.onCreate（savedInstanceState）
setContentView（R.layout.activity_main）
//***删除***下面的行。
val按钮：按钮=findViewById（R.id.changeText_按钮）
changeText_Button.setOnClickListener{
changeText（）
}
}

使用延迟初始化：

在这种方法中，属性（局部变量）将具有非在声明站点中首次访问的值，因此，通过这种方式，我们可以将视图设置为全局属性，例如：

val text:TextView由lazy{findViewById（R.id.text_TextView）}
重写创建时的乐趣（savedInstanceState:Bundle？）{
super.onCreate（savedInstanceState）
setContentView（R.layout.activity_main）
...
}

您的活动是否在manifest.xml中声明？

=com.google.android.gms/com.google.android.location.internal.server.HardwareArProviderService }: process is bad
2020-09-14 13:57:42.606 556-580/? I/ActivityManager: Exiting empty application process 0:com.google.android.gms.persistent/u0a102 (null)
2020-09-14 13:57:42.610 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)
        at com.android.server.am.ActivityManagerService.startProcessLocked(ActivityManagerService.java:3148)
        at com.android.server.am.ActiveServices.bringUpServiceLocked(ActiveServices.java:2946)
        at com.android.server.am.ActiveServices.bindServiceLocked(ActiveServices.java:2062)
        at com.android.server.am.ActivityManagerService.bindIsolatedService(ActivityManagerService.java:15158)
        at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1833)
        at android.app.ContextImpl.bindServiceAsUser(ContextImpl.java:1783)
        at com.android.server.ServiceWatcher.rebind(ServiceWatcher.java:339)
        at com.android.server.ServiceWatcher.onBestServiceChanged(ServiceWatcher.java:310)
        at com.android.server.ServiceWatcher.onBindingDied(ServiceWatcher.java:391)
        at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1950)
        at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1986)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.os.HandlerThread.run(HandlerThread.java:67)
        at com.android.server.ServiceThread.run(ServiceThread.java:44)
2020-09-14 13:57:42.610 556-577/? I/ActivityManager: Force stopping com.google.android.gms appid=10102 user=0: start failure
2020-09-14 13:57:42.611 556-577/? I/ActivityManager:   Force stopping service ServiceRecord{946b99 u0 com.google.android.gms/com.google.android.location.network.NetworkLocationService}
2020-09-14 13:57:42.612 556-577/? W/ActivityManager: Unable to launch app com.google.android.gms/10102 for service Intent { act=com.android.location.service.v3.NetworkLocationProvider cmp=com.google.android.gms/com.google.android.location.network.NetworkLocationService }: process is bad
2020-09-14 13:57:42.613 556-580/? I/ActivityManager: Exiting empty application process 0:com.google.android.gms.persistent/u0a102 (null)
2020-09-14 13:57:42.617 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)
        at com.android.server.am.ActivityManagerService.startProcessLocked(ActivityManagerService.java:3148)
        at com.android.server.am.ActiveServices.bringUpServiceLocked(ActiveServices.java:2946)
        at com.android.server.am.ActiveServices.bindServiceLocked(ActiveServices.java:2062)
        at com.android.server.am.ActivityManagerService.bindIsolatedService(ActivityManagerService.java:15158)
        at android.app.ContextImpl.bindServiceCommon(ContextImpl.java:1833)
        at android.app.ContextImpl.bindServiceAsUser(ContextImpl.java:1783)
        at com.android.server.ServiceWatcher.rebind(ServiceWatcher.java:339)
        at com.android.server.ServiceWatcher.onBestServiceChanged(ServiceWatcher.java:310)
        at com.android.server.ServiceWatcher.onBindingDied(ServiceWatcher.java:391)
        at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1950)
        at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1986)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.os.HandlerThread.run(HandlerThread.java:67)
        at com.android.server.ServiceThread.run(ServiceThread.java:44)
2020-09-14 13:57:42.617 556-577/? I/ActivityManager: Force stopping com.google.android.gms appid=10102 user=0: start failure
2020-09-14 13:57:42.618 556-577/? I/ActivityManager:   Force stopping service ServiceRecord{d84426a u0 com.google.android.gms/com.google.android.location.fused.FusedLocationService}
2020-09-14 13:57:42.618 556-577/? W/ActivityManager: Unable to launch app com.google.android.gms/10102 for service Intent { act=com.android.location.service.FusedLocationProvider cmp=com.google.android.gms/com.google.android.location.fused.FusedLocationService }: process is bad
2020-09-14 13:57:42.622 556-577/? E/ActivityManager: Failure starting process com.google.android.gms.persistent
    java.lang.SecurityException: Package com.google.android.gms is currently frozen!
        at com.android.server.pm.PackageManagerService.checkPackageStartable(PackageManagerService.java:4451)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:1757)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2319)
        at com.android.server.am.ProcessList.startProcessLocked(ProcessList.java:2441)