E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.hosexam.demoapp, PID: 9221
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.ref.WeakReference.get()' on a null object reference
        at com.openharmony.filepicker.config.FilePickerConfig.forResult(Unknown Source:18)
        at com.hosexam.demoapp.MainAbility$4.onClick(MainAbility.java:191)
        at ohos.agp.window.wmc.AGPEngineAdapter.nativeDispatchTouchEvent(Native Method)
        at ohos.agp.window.wmc.AGPEngineAdapter.processTouchEvent(AGPEngineAdapter.java:196)
        at ohos.agp.window.wmc.AGPWindow.dispatchTouchEvent(AGPWindow.java:749)
        at ohos.aafwk.ability.AbilityWindow.dispatchTouchEvent(AbilityWindow.java:413)
        at ohos.aafwk.ability.Ability.dispatchTouchEvent(Ability.java:1096)
        at ohos.abilityshell.AbilityShellActivityDelegate.convertTouchEventThenDispatch(AbilityShellActivityDelegate.java:628)
        at ohos.abilityshell.AbilityShellActivity.dispatchTouchEvent(AbilityShellActivity.java:162)
        at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:685)
        at android.view.View.dispatchPointerEvent(View.java:13957)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:6420)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:6215)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5604)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:5657)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:5623)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:5781)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:5631)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:5838)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5604)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:5657)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:5623)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:5631)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:5604)
        at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:8698)
        at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:8618)
        at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:8571)
        at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:8956)
        at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:239)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:363)
        at android.os.Looper.loop(Looper.java:176)
        at android.app.ActivityThread.main(ActivityThread.java:8668)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1109)