Question

所以我创建了一个名为BagActivity的活动，它的适配器等已经删除了，因为不再需要它。我清理构建项目，从测试设备卸载apk但是，我收到以下错误：

FATAL EXCEPTION: main
                                                                  Process: in.ddas.pretense, PID: 11858
                                                                  java.lang.RuntimeException: Unable to start activity ComponentInfo{in.ddas.pretense/in.ddas.pretense.BagActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
                                                                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
                                                                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
                                                                      at android.app.ActivityThread.access$800(ActivityThread.java:144)
                                                                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
                                                                      at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                      at android.os.Looper.loop(Looper.java:135)
                                                                      at android.app.ActivityThread.main(ActivityThread.java:5221)
                                                                      at java.lang.reflect.Method.invoke(Native Method)
                                                                      at java.lang.reflect.Method.invoke(Method.java:372)
                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
                                                                   Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
                                                                      at in.ddas.pretense.BagActivity.onCreate(BagActivity.java:28)
                                                                      at android.app.Activity.performCreate(Activity.java:5933)
                                                                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
                                                                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
                                                                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360) 
                                                                      at android.app.ActivityThread.access$800(ActivityThread.java:144) 
                                                                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278) 
                                                                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                      at android.os.Looper.loop(Looper.java:135) 
                                                                      at android.app.ActivityThread.main(ActivityThread.java:5221) 
                                                                      at java.lang.reflect.Method.invoke(Native Method) 
                                                                      at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
                                                                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

似乎有什么问题？感谢。

编辑：如果我在其他测试设备中运行此应用程序，则此错误不会显示！为什么要为1台设备展示它？

Answer 1

您似乎还没有删除所有BugActivity员工。

你有例外：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
           at in.ddas.pretense.BagActivity.onCreate(BagActivity.java:28)

它引起了第二个例外。所以它说你尝试在BagActivity的onCreate方法中使用null RecyclerView对象。您可以删除BagActivity的布局而不删除活动类。

活动不存在时无法启动活动ComponentInfo

1 个答案: