为啥尝试在 GoogleMap 上放置标记时出现 NullPointerException？
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【中文标题】为啥尝试在 GoogleMap 上放置标记时出现 NullPointerException？【英文标题】：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
【参考方案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。以上是关于为啥尝试在 GoogleMap 上放置标记时出现 NullPointerException？的主要内容，如果未能解决你的问题，请参考以下文章
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