java - 尝试使用 AdMob 时 Android Studio 出错(运行时崩溃)

Question

按下运行按钮并将其定向到我的 adb 设备(运行 2.30.401.1、Android 6.0 的 HTC One M9 Plus，如果您不知道 HTC 版本号，如果它使任何差异)。

这是 Android Studio 的 logcat 日志

java.lang.RuntimeException: Unable to start activity 
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.ads.AdView.loadAd(com.google.android.gms.ads.AdRequest)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2611)                                                                              
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2677)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1515)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:227)
at android.app.ActivityThread.main(ActivityThread.java:6100)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:859)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 
'void com.google.android.gms.ads.AdView.loadAd(com.google.android.gms.ads.AdRequest)' 
on a null object reference
at com.groverstudios.applestore.MainActivity.onCreate(MainActivity.java:39)
at android.app.Activity.performCreate(Activity.java:6280)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1131)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2564)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2677) 
at android.app.ActivityThread.-wrap11(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1515) 
at android.os.Handler.dispatchMessage(Handler.java:111) 
at android.os.Looper.loop(Looper.java:227) 
at android.app.ActivityThread.main(ActivityThread.java:6100) 
at java.lang.reflect.Method.invoke(Native Method) 
at co m.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:859) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:749) 

欢迎任何帮助，提前致谢:)

Answer 1

你的错误很清楚地说明了发生了什么

java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.ads.AdView.loadAd(com.google.android.gms.ads.AdRequest)' on a null object reference

因此，您有一个指向 AdView 的成员或变量，并且该成员或变量为 null。在调用 .loadAd(...) 方法之前，您需要执行 .findViewById(R.id.name_of_your_adview) 操作。