Android Google Drive客户端API+；安卓不工作

我正在尝试写一个android应用程序作为一个初学者，并没有运气到目前为止！！我正在尝试从用户驱动器帐户获取图像文件列表。通过我的探索，我了解到Google Drive for Android API并没有提供完整的访问范围。所以我必须使用Google API for Java客户端。我试着下载了。此任务应用程序在我的手机上运行良好。所以现在我把这个应用程序改成了谷歌硬盘。但它总是抛出一个例外。代码中的第38行读作

client.files（）.list（）.execute（）.getItems（）//客户端被定义为其他文件中的驱动器变量，我正在尝试从用户帐户获取文件列表

例外情况是：

08-24 15:00:33.712  15422-15473/gattasrikanth.googledrive.example E/DriveSample﹕ Error
com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAuthIOException
        at com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential$RequestHandler.intercept(GoogleAccountCredential.java:286)
        at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:859)
        at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:410)
        at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:343)
        at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:460)
        at gattasrikanth.googledrive.example.AsyncLoadTasks.doInBackground(AsyncLoadTasks.java:40)
        at gattasrikanth.googledrive.example.CommonAsyncTask.doInBackground(CommonAsyncTask.java:57)
        at gattasrikanth.googledrive.example.CommonAsyncTask.doInBackground(CommonAsyncTask.java:35)
        at android.os.AsyncTask$2.call(AsyncTask.java:288)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:841)
 Caused by: com.google.android.gms.auth.GoogleAuthException: Unknown
        at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source)
        at com.google.android.gms.auth.GoogleAuthUtil.getToken(Unknown Source)
        at com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential.getToken(GoogleAccountCredential.java:255)
        at com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential$RequestHandler.intercept(GoogleAccountCredential.java:279)
            at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:859)
            at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:410)
            at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:343)
            at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:460)
            at gattasrikanth.googledrive.example.AsyncLoadTasks.doInBackground(AsyncLoadTasks.java:40)
            at gattasrikanth.googledrive.example.CommonAsyncTask.doInBackground(CommonAsyncTask.java:57)
            at gattasrikanth.googledrive.example.CommonAsyncTask.doInBackground(CommonAsyncTask.java:35)
            at android.os.AsyncTask$2.call(AsyncTask.java:288)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:841)

知道我哪里做错了吗。
我已经在谷歌控制台上正确设置了项目、软件包和SHA1。
不确定为什么它与TasksAPI一起工作，而与驱动器API不一起工作。
为什么需要完整的驱动器作用域？要读取任何给定/根文件夹中可用的所有列表图像/文件。请尝试此-可能这对您有帮助，此-是！！这正是我所需要和帮助的！虽然几天前我就解决了。谢谢分享这些链接！