嘗試使用AdMob時發生Android Studio錯誤（運行時崩潰）

Question

按下運行按鈕並將其定向到我的adb設備后，我的應用程序出現了問題（如果您不知道HTC版本號（如果有所不同），則為運行2.30.401.1，Android 6.0的HTC One M9 Plus）。

這是來自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) 

歡迎任何幫助，在此先感謝:)

Answer 1

您的錯誤說的很清楚

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，您有一個指向AdView的成員或變量，因此為null。 在調用.loadAd(...)方法之前，需要先執行.findViewById(R.id.name_of_your_adview) 。