我如何获得java.lang.nullpointerexception?

kcrjzv8t  于 2021-08-25  发布在  Java
关注(0)|答案(0)|浏览(380)

当我找到答案时,我会狠狠地揍自己一顿,但我很困惑,所以:
我得到一份工作 NullPointerException 尝试访问onedrive时(某些)用户报告。当然我自己不能复制它。我正在使用微软的onedrive sdk。 FileListItem 是我试图填充到 success() sdk回调的方法。错误的位置来自google play开发者控制台错误详细信息中的堆栈跟踪。

final ICallback<IItemCollectionPage> callback = new ICallback<IItemCollectionPage>() {
    @Override
    public void success(final IItemCollectionPage result) {
        for (Item child : result.getCurrentPage()) {
            FileListItem item = new FileListItem();
            item.name = child.name;
            if (child.parentReference != null) {
                item.sourcePath = child.parentReference.path;  // java.lang.NullPointerException
            }
            ...

所以 child 来自 for 循环遍历传递给的(可能有效)列表 success() ,它不会撞坏 child.name ,及 child.parentReference != null .
我的问题是 item 是我刚刚创建的有效对象,并且 child.parentReference != null ,这些用户如何获得 NullPointerException ?
编辑以添加完整堆栈跟踪:

java.lang.NullPointerException: 
  at [myapp].OneDriveProvider$4.success (OneDriveProvider.java:183)
  at [myapp].OneDriveProvider$4.success (OneDriveProvider.java:176)
  at com.onedrive.sdk.concurrency.DefaultExecutors$1.run (DefaultExecutors.java:88)
  at com.onedrive.sdk.concurrency.SynchronousExecutor$1.onPostExecute (SynchronousExecutor.java:54)
  at com.onedrive.sdk.concurrency.SynchronousExecutor$1.onPostExecute (SynchronousExecutor.java:46)
  at android.os.AsyncTask.finish (AsyncTask.java:755)
  at android.os.AsyncTask.access$900 (AsyncTask.java:192)
  at android.os.AsyncTask$InternalHandler.handleMessage (AsyncTask.java:772)
  at android.os.Handler.dispatchMessage (Handler.java:107)
  at android.os.Looper.loop (Looper.java:214)
  at android.app.ActivityThread.main (ActivityThread.java:7397)
  at java.lang.reflect.Method.invoke (Native Method)
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:492)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:935)

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