Android sdk:java.lang.NullPointerException:尝试调用虚方法

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当我尝试在我的设备上调试应用程序并尝试在几个小时内摆脱它时,我收到此错误…并且无法弄清楚…如果有人能找到解决方案,那将是非常棒的,因为我想要尽快为我的应用发布新的更新..
  1. 07-05 22:45:02.550 2821-2821/davvarn.csgo_maps E/AndroidRuntime FATAL EXCEPTION: main
  2. Process: davvarn.csgo_maps,PID: 2821
  3. java.lang.RuntimeException: Unable to start activity ComponentInfo{davvarn.csgo_maps/davvarn.csgo_maps.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageDrawable(android.graphics.drawable.Drawable)' on a null object reference
  4. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2356)
  5. at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2418)
  6. at android.app.ActivityThread.access$900(ActivityThread.java:154)
  7. at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
  8. at android.os.Handler.dispatchMessage(Handler.java:102)
  9. at android.os.Looper.loop(Looper.java:135)
  10. at android.app.ActivityThread.main(ActivityThread.java:5289)
  11. at java.lang.reflect.Method.invoke(Native Method)
  12. at java.lang.reflect.Method.invoke(Method.java:372)
  13. at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
  14. at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)
  15. Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageDrawable(android.graphics.drawable.Drawable)' on a null object reference
  16. at davvarn.csgo_maps.MainActivity.changeContent(MainActivity.java:176)
  17. at davvarn.csgo_maps.MainActivity.onCreate(MainActivity.java:115)
  18. at android.app.Activity.performCreate(Activity.java:5990)
  19. at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
  20. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2309)
  21. at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2418)
  22. at android.app.ActivityThread.access$900(ActivityThread.java:154)
  23. at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
  24. at android.os.Handler.dispatchMessage(Handler.java:102)
  25. at android.os.Looper.loop(Looper.java:135)
  26. at android.app.ActivityThread.main(ActivityThread.java:5289)
  27. at java.lang.reflect.Method.invoke(Native Method)
  28. at java.lang.reflect.Method.invoke(Method.java:372)
  29. at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
  30. at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

我真的不知道如何粘贴MainActivity文件,因为我是Stackoverflow的新手.请让我知道如何,我会尝试.

解决方法

@H_502_9@ 确保已初始化图像视图并使用XML中定义的正确ID.您可以像这样初始化ImageView:

ImageView imageView =(ImageView)findViewById(R.id.yourImageViewIDHere);

在onCreate调用setContentView之后,请执行此操作.

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