我正在将BOX.COM与我的android应用程序集成。所以我使用BoxAndroidLibraryV2与我的app.I可以上传文件，但下载文件导致错误。下面是我正在使用的代码。
if (object instanceof BoxAndroidFile) {
// downloadFile((BoxAndroidFile) object);
try {
startActivityForResult(FilePickerActivity.getLaunchIntent(
BoxDotComAddDocumentActivity.this, currentFolderId,
(BoxAndroidOAuthData) getClient().getAuthData(),
IBMECMApp.CLIENT_ID, IBMECMApp.CLIENT_SECRET),
PICK_FILE_REQUEST);
} catch (AuthFatalFailureException e) {
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode,
Intent intent) {
Log.i(TAG, "requestCode " + requestCode + " resultCode " + resultCode);
switch (requestCode) {
case PICK_FILE_REQUEST:
if (resultCode == Activity.RESULT_CANCELED) {
Toast.makeText(this, "No file chosen", Toast.LENGTH_LONG)
.show();
} else {
BoxAndroidFile file = intent
.getParcelableExtra(FilePickerActivity.EXTRA_BOX_ANDROID_FILE);
downloadFile(file);
}
break;
}
}
public void downloadFile(final BoxAndroidFile file) {
Toast.makeText(BoxDotComAddDocumentActivity.this,
"Starting download..." + file.getName(), Toast.LENGTH_LONG)
.show();
new AsyncTask<BoxAndroidFile, Void, Boolean>() {
@Override
protected Boolean doInBackground(BoxAndroidFile... arg0) {
try {
File f = new File(getFilesDir(), file.getName());
Log.i(TAG,
"File name is " + file.getName() + " getFilesDir "
+ getFilesDir() + " file.getId() "
+ file.getId() + "f name " + f.getName());
getClient().getFilesManager().downloadFile(file.getId(), f,
null, null);
} catch (Exception e) {
Log.e(TAG, "An error occurred when downloading a file.", e);
return false;
}
return true;
}
@Override
protected void onPostExecute(Boolean result) {
if (result) {
Toast.makeText(BoxDotComAddDocumentActivity.this,
"Successfully downloaded " + file.getName() + ".",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(BoxDotComAddDocumentActivity.this,
"An error occurred when downloading.",
Toast.LENGTH_LONG).show();
}
}
}.execute(file);
}
跟随是logcat响应，同时出现错误
07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): An error occurred when downloading a file. 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): java.lang.NullPointerException: Attempt to invoke interface method 'void com.box.boxjavalibv2.filetransfer.IFileTransferListener.onProgress(long)' on a null object reference 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.box.boxjavalibv2.filetransfer.BoxFileDownload.copyOut(BoxFileDownload.java:262) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.box.boxjavalibv2.filetransfer.BoxFileDownload.execute(BoxFileDownload.java:124) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.box.boxjavalibv2.filetransfer.BoxFileDownload.execute(BoxFileDownload.java:153) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.box.boxjavalibv2.resourcemanagers.BoxFilesManagerImpl.downloadFile(BoxFilesManagerImpl.java:151) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.filenet.ecm.activites.BoxDotComAddDocumentActivity$2.doInBackground(BoxDotComAddDocumentActivity.java:200) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at com.filenet.ecm.activites.BoxDotComAddDocumentActivity$2.doInBackground(BoxDotComAddDocumentActivity.java:1) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at android.os.AsyncTask$2.call(AsyncTask.java:288) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at java.util.concurrent.FutureTask.run(FutureTask.java:237) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 07-30 12:07:05.947: E/BoxDotComAddDocumentActivity(1419): at java.lang.Thread.run(Thread.java:818)