为什么尝试在 GoogleMap 上放置标记时出现 NullPointerException？

【问题标题】：Why am I getting a NullPointerException When Attempting To Place a Marker on GoogleMap?为什么尝试在 GoogleMap 上放置标记时出现 NullPointerException？
【发布时间】：2021-11-30 03:49:22
【问题描述】：

我在让 Google Map SDK 显示在我的 Kotlin android 项目的片段中时遇到问题。

地图有时会显示，有时不会。我可能会运行该应用程序（绿色播放按钮 Android Studio）一次，它会工作，关闭并再次运行它，它会崩溃，尽管代码本身没有更改。

尝试放置地图标记也经常导致应用程序崩溃，有时它会显示，有时它会崩溃......

这是片段代码：

class global_map : Fragment(), OnMapReadyCallback{

    private lateinit var mMap: GoogleMap

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_global_map, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)

        val mapFragment: SupportMapFragment = childFragmentManager.findFragmentById(R.id.mapFragment) as SupportMapFragment
        mapFragment.getMapAsync(this)
    }
    

    override fun onMapReady(googleMap: GoogleMap) {
       mMap = googleMap
        mMap.addMarker(
            MarkerOptions().position(LatLng(0.0, 0.0)).title("Test")
        )
    }
}

就Logcat的数据而言，请在下面找到：

2021-10-11 14:31:34.747 6751-6751/co.uk.myapp.app W/Resources: Drawable com.google.android.gms.dynamite_mapsdynamite:drawable/maps_watermark_color has unresolved theme attributes! Consider using Resources.getDrawable(int, Theme) or Context.getDrawable(int).
    java.lang.RuntimeException
        at android.content.res.Resources.getDrawable(Resources.java:899)
        at com.google.maps.api.android.lib6.impl.ax.m(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):5)
        at com.google.maps.api.android.lib6.impl.fh.<init>(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):3)
        at com.google.maps.api.android.lib6.impl.bo.az(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):16)
        at com.google.maps.api.android.lib6.impl.cr.o(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):2)
        at com.google.android.gms.maps.internal.o.aX(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):22)
        at dx.onTransact(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):4)
        at android.os.Binder.transact(Binder.java:1043)
        at com.google.android.gms.internal.maps.zza.zzH(com.google.android.gms:play-services-maps@@17.0.1:2)
        at com.google.android.gms.maps.internal.zzk.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:5)
        at com.google.android.gms.maps.zzau.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:7)
        at com.google.android.gms.dynamic.zad.zaa(Unknown Source:4)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.zaa(Unknown Source:9)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.onCreateView(Unknown Source:25)
        at com.google.android.gms.maps.SupportMapFragment.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:1)
        at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:112)
        at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1647)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3128)
        at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3065)
        at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2988)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2100)
        at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3138)
        at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:3072)
        at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:251)
        at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:502)
        at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:246)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1435)
        at android.app.Activity.performStart(Activity.java:8024)
        at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3475)
        at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
        at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
2021-10-11 14:31:34.747 6751-6751/co.uk.myapp.app W/Resources:     at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2021-10-11 14:31:34.774 6751-6751/co.uk.myapp.app W/Resources: Drawable com.google.android.gms.dynamite_mapsdynamite:drawable/maps_btn_myl has unresolved theme attributes! Consider using Resources.getDrawable(int, Theme) or Context.getDrawable(int).
    java.lang.RuntimeException
        at android.content.res.Resources.getDrawable(Resources.java:899)
        at com.google.maps.api.android.lib6.impl.ax.m(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):5)
        at com.google.maps.api.android.lib6.impl.w.<init>(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):8)
        at com.google.maps.api.android.lib6.impl.bo.az(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):20)
        at com.google.maps.api.android.lib6.impl.cr.o(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):2)
        at com.google.android.gms.maps.internal.o.aX(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):22)
        at dx.onTransact(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):4)
        at android.os.Binder.transact(Binder.java:1043)
        at com.google.android.gms.internal.maps.zza.zzH(com.google.android.gms:play-services-maps@@17.0.1:2)
        at com.google.android.gms.maps.internal.zzk.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:5)
        at com.google.android.gms.maps.zzau.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:7)
        at com.google.android.gms.dynamic.zad.zaa(Unknown Source:4)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.zaa(Unknown Source:9)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.onCreateView(Unknown Source:25)
        at com.google.android.gms.maps.SupportMapFragment.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:1)
        at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:112)
        at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1647)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3128)
        at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3065)
        at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2988)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2100)
        at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3138)
        at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:3072)
        at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:251)
        at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:502)
        at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:246)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1435)
        at android.app.Activity.performStart(Activity.java:8024)
        at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3475)
        at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
        at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
2021-10-11 14:31:34.775 6751-6751/co.uk.myapp.app W/Resources:     at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2021-10-11 14:31:34.784 6751-6751/co.uk.myapp.app W/Resources: Drawable com.google.android.gms.dynamite_mapsdynamite:drawable/maps_btn_zoom_down has unresolved theme attributes! Consider using Resources.getDrawable(int, Theme) or Context.getDrawable(int).
    java.lang.RuntimeException
        at android.content.res.Resources.getDrawable(Resources.java:899)
        at com.google.maps.api.android.lib6.impl.ax.m(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):5)
        at com.google.maps.api.android.lib6.impl.w.<init>(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):30)
        at com.google.maps.api.android.lib6.impl.bo.az(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):20)
        at com.google.maps.api.android.lib6.impl.cr.o(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):2)
        at com.google.android.gms.maps.internal.o.aX(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):22)
        at dx.onTransact(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):4)
        at android.os.Binder.transact(Binder.java:1043)
        at com.google.android.gms.internal.maps.zza.zzH(com.google.android.gms:play-services-maps@@17.0.1:2)
        at com.google.android.gms.maps.internal.zzk.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:5)
        at com.google.android.gms.maps.zzau.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:7)
        at com.google.android.gms.dynamic.zad.zaa(Unknown Source:4)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.zaa(Unknown Source:9)
        at com.google.android.gms.dynamic.DeferredLifecycleHelper.onCreateView(Unknown Source:25)
        at com.google.android.gms.maps.SupportMapFragment.onCreateView(com.google.android.gms:play-services-maps@@17.0.1:1)
        at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentStore.moveToExpectedState(FragmentStore.java:112)
        at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1647)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3128)
        at androidx.fragment.app.FragmentManager.dispatchViewCreated(FragmentManager.java:3065)
        at androidx.fragment.app.Fragment.performViewCreated(Fragment.java:2988)
        at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:546)
        at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282)
        at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189)
        at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2100)
        at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002)
        at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:3138)
        at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:3072)
        at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:251)
        at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:502)
        at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:246)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1435)
        at android.app.Activity.performStart(Activity.java:8024)
        at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3475)
        at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
        at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
2021-10-11 14:31:34.784 6751-6751/co.uk.myapp.app W/Resources:     at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
2021-10-11 14:31:34.932 6751-6774/co.uk.myapp.app W/AdrenoUtils: <ReadGpuID_from_sysfs:197>: Failed to open /sys/class/kgsl/kgsl-3d0/gpu_model
2021-10-11 14:31:34.932 6751-6774/co.uk.myapp.app W/AdrenoUtils: <ReadGpuID:221>: Failed to read chip ID from gpu_model. Fallback to use the GSL path
2021-10-11 14:31:35.014 6751-6774/co.uk.myapp.app W/Gralloc3: mapper 3.x is not supported
2021-10-11 14:31:35.020 6751-6816/co.uk.myapp.app E/AndroidRuntime: FATAL EXCEPTION: GLThread 24197
    Process: co.uk.myapp.app, PID: 6751
    java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.Bitmap.getWidth()' on a null object reference
        at com.google.maps.api.android.lib6.gmm6.vector.gl.aj.b(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):11)
        at com.google.maps.api.android.lib6.gmm6.vector.gl.aj.<init>(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):3)
        at com.google.maps.api.android.lib6.gmm6.vector.gl.g.<init>(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):18)
        at com.google.maps.api.android.lib6.gmm6.vector.bs.d(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):14)
        at com.google.maps.api.android.lib6.gmm6.vector.av.run(:com.google.android.gms.dynamite_mapsdynamite@213614097@21.36.14 (150400-0):45)
2021-10-11 14:31:35.028 1500-2253/? W/ActivityTaskManager:   Force finishing activity co.uk.myapp.app/.MainActivity

【问题讨论】：

  • 由于 NPE 在 API 类内部，我们需要查看更多堆栈跟踪。
  • 感谢@Tenfour04，我已经包含了来自 logcat 的更多数据。我在清单中有我的 API 密钥，在我的 Gradle 中有 implementation 'com.google.android.gms:play-services-maps:17.0.1'，我在 YouTube 和 Google 文档（针对 Activity 而不是 Fragment）上遵循了许多教程，但我仍然遇到很多问题。
  • 这很烦人，因为有时它会在我运行它时工作一次，然后如果我应用更改并再次构建它，它就会崩溃

标签： kotlin android-fragments google-maps-markers


【解决方案1】：

这可能是也可能不是问题的根源。只是猜测。

由于地图是异步创建的，因此可能会在 Fragment 处于分离状态时调用 onMapReady，在这种情况下，地图视图将不会使用关联的上下文和主题。也许这导致它在检索其可绘制资源时出错。我会将您的代码更改如下：

override fun onMapReady(googleMap: GoogleMap) {
    context ?: return // Fragment has been detached--don't do anything.
    mMap = googleMap
    mMap.addMarker(
        MarkerOptions().position(LatLng(0.0, 0.0)).title("Test")
    )
}

或者：

override fun onMapReady(googleMap: GoogleMap) {
    if (isDetached) return
    mMap = googleMap
    mMap.addMarker(
        MarkerOptions().position(LatLng(0.0, 0.0)).title("Test")
    )
}

【讨论】：

  • 感谢您的回答。这当然可以解释为什么有时它可以在构建上工作，而其他时候却不行。我会尽快报告
  • 不幸的是，我仍然遇到同样的错误，NPE 与可绘制对象有关。我将在我的另一个项目中尝试该代码，看看它是否也一样。
  • 如果有帮助，如果我清除应用程序的缓存，应用程序实际上会恢复正常工作。如果我在 Android Studio 中使用“Apply Changes and Restart Activty”，它会导致它再次崩溃（直到缓存被清除）
  • 哦，这完全在意料之中！ “应用更改并重新启动”有时会起作用，因为它试图在不重新编译的情况下热交换代码。任何影响资源的更改都会导致它无法工作。还有其他类型的更改也会导致它失败，例如从类中添加或删除属性或更改函数签名。这在 Android Studio 的开发人员指南中有记录。大多数时候你应该使用 Run 来重建你的应用程序。应用更改仅适用于 Java/Kotlin 代码中的微小更改。
  • 好的，非常感谢，我担心如果我在 Play 商店上发布它，我必须继续清除我的缓存以及任何用户都必须这样做。
猜你喜欢
  • 1970-01-01
  • 2015-10-06
  • 2010-12-11
  • 2012-11-20
  • 1970-01-01
  • 2017-07-22
  • 2020-06-29
  • 1970-01-01
  • 1970-01-01
相关资源
最近更新 更多
热门标签
Java Python linux javascript Mysql C# Docker 算法 前端 SpringBoot Redis Vue spring 设计模式 .net core .net kubernetes c++ 数据库 数据结构 大数据 js 机器学习 微服务 Android Go 程序员 面试 JVM ASP.net core 云原生 人工智能 后端 PHP git CSS golang k8s Nginx Django mybatis 深度学习 多线程 React 架构 devops 爬虫 云计算 Spring Boot LeetCode