安卓应用程序在添加SharedPreference写后崩溃

Question

多亏了这个网站，我的应用程序进展得很好。但是，当切换到我刚刚创建的新活动时，它会崩溃。有6个活动，用户回答问题，在活动#5的顺序，应用程序崩溃时，我按下继续按钮。我得到了标准“不幸的是，应用程序已经停止了。”当我按OK键时，应用程序关闭并重新打开，我被带回到活动#4，它保留了我保存到SharedPreferences中的用户输入。

从我按“继续”按钮时开始记录：

02-27 08:42:54.231 7307-7307/com.health.hermes D/ViewRootImpl: MSG_RESIZED: ci=Rect(0, 96 - 0, 0) vi=Rect(0, 96 - 0, 0) or=1
02-27 08:42:54.541 7307-7307/com.health.hermes D/ViewRootImpl: ViewPostImeInputStage processPointer 0
02-27 08:42:54.611 7307-7307/com.health.hermes D/ViewRootImpl: ViewPostImeInputStage processPointer 1
02-27 08:42:54.621 7307-7307/com.health.hermes I/Timeline: Timeline: Activity_launch_request id:com.health.hermes time:1000022770
02-27 08:42:54.681 7307-7307/com.health.hermes D/TextView: setTypeface with style : 0
02-27 08:42:54.681 7307-7307/com.health.hermes D/TextView: setTypeface with style : 0
02-27 08:42:54.691 7307-7307/com.health.hermes D/AndroidRuntime: Shutting down VM
02-27 08:42:54.691 7307-7307/com.health.hermes E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.health.hermes, PID: 7307
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.health.hermes/com.health.hermes.KiPercentActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setFilters(android.text.InputFilter[])' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3253)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
        at android.app.ActivityThread.access$1100(ActivityThread.java:221)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:158)
        at android.app.ActivityThread.main(ActivityThread.java:7225)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setFilters(android.text.InputFilter[])' on a null object reference
        at com.health.hermes.KiPercentActivity.onCreate(KiPercentActivity.java:30)
        at android.app.Activity.performCreate(Activity.java:6876)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349) 
        at android.app.ActivityThread.access$1100(ActivityThread.java:221) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:158) 
        at android.app.ActivityThread.main(ActivityThread.java:7225) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 

如果你看到了原因，请指出我如何能更好地理解逻辑猫，以便我可以开始诊断自己。谢谢!

Answer 1

这是你的答案。

由: android.widget.EditText.setFilters(android.text.InputFilter[])‘引发:尝试在com.health.hermes.KiPercentActivity.onCreate(KiPercentActivity.java:30) at android.app.Activity.performCreate(Activity.java:6876) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)上调用空对象引用上的虚拟方法’android.app.Activity.performCreate(Activity.java:6876)‘

您的EditText为空，这就是发生这种情况的原因。

UPDATE多项最终为null，谢谢您花时间查看我的日志。已在此回答：

What is a NullPointerException, and how do I fix it?