我有以下问题。我正在使用 DropBox SDK 将文件上传到工作正常的 Dropbox。上传文件时（在 AsyncTask 内），将显示带有取消按钮的 ProgressDialog，在这里仍然可以。不能正常工作的是，当按下取消按钮时，会引发 NetworkOnMainThreadException。我是 Android 编程新手，但我怀疑它与构造函数中的 ProgressDialog 有关。因为它不在“doInBackground”部分。
试图通过实现 OnDismissListener 并进行 onDismiss 中止来修复它，但仍然没有运气。调用“mRequest.abort()”时出现错误。提前感谢您的任何答案！
所以这是我的代码
public class DropBoxUpload extends AsyncTask<Void, Long, Boolean> implements OnDismissListener {
private DropboxAPI<?> mApi;
private String mPath;
private File mFile;
private long mFileLen;
private UploadRequest mRequest;
private Context mContext;
private final ProgressDialog mDialog;
private String mErrorMsg;
public DropBoxUpload(Context context, DropboxAPI<?> api, String dropboxPath, File file) {
// We set the context this way so we don't accidentally leak activities
mContext = context.getApplicationContext();
mFileLen = file.length();
mApi = api;
mPath = dropboxPath;
mFile = file;
mDialog = new ProgressDialog(context);
mDialog.setMax(100);
mDialog.setMessage("Uploading " + file.getName());
mDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mDialog.setProgress(0);
mDialog.setButton("Cancel", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// This will cancel the putFile operation
mDialog.dismiss();
}
});
mDialog.setCancelable(true);
mDialog.setOnDismissListener(this);
mDialog.show();
}
@Override
protected Boolean doInBackground(Void... params) {
try {
// By creating a request, we get a handle to the putFile operation,
// so we can cancel it later if we want to
FileInputStream fis = new FileInputStream(mFile);
String path = mPath + mFile.getName();
mRequest = mApi.putFileOverwriteRequest(path, fis, mFile.length(),
new ProgressListener() {
@Override
public long progressInterval() {
// Update the progress bar every half-second or so
return 500;
}
@Override
public void onProgress(long bytes, long total) {
publishProgress(bytes);
}
});
if (mRequest != null) {
mRequest.upload();
return true;
}
} catch (DropboxUnlinkedException e) {
// This session wasn't authenticated properly or user unlinked
mErrorMsg = "This app wasn't authenticated properly.";
} catch (DropboxFileSizeException e) {
// File size too big to upload via the API
mErrorMsg = "This file is too big to upload";
} catch (DropboxPartialFileException e) {
// We canceled the operation
mErrorMsg = "Upload canceled";
} catch (DropboxServerException e) {
// Server-side exception. These are examples of what could happen,
// but we don't do anything special with them here.
if (e.error == DropboxServerException._401_UNAUTHORIZED) {
// Unauthorized, so we should unlink them. You may want to
// automatically log the user out in this case.
} else if (e.error == DropboxServerException._403_FORBIDDEN) {
// Not allowed to access this
} else if (e.error == DropboxServerException._404_NOT_FOUND) {
// path not found (or if it was the thumbnail, can't be
// thumbnailed)
} else if (e.error == DropboxServerException._507_INSUFFICIENT_STORAGE) {
// user is over quota
} else {
// Something else
}
// This gets the Dropbox error, translated into the user's language
mErrorMsg = e.body.userError;
if (mErrorMsg == null) {
mErrorMsg = e.body.error;
}
} catch (DropboxIOException e) {
// Happens all the time, probably want to retry automatically.
mErrorMsg = "Network error. Try again.";
} catch (DropboxParseException e) {
// Probably due to Dropbox server restarting, should retry
mErrorMsg = "Dropbox error. Try again.";
} catch (DropboxException e) {
// Unknown error
mErrorMsg = "Unknown error. Try again.";
} catch (FileNotFoundException e) {
}
return false;
}
@Override
protected void onProgressUpdate(Long... progress) {
int percent = (int)(100.0*(double)progress[0]/mFileLen + 0.5);
mDialog.setProgress(percent);
}
@Override
protected void onPostExecute(Boolean result) {
mDialog.dismiss();
}
@Override
public void onDismiss(DialogInterface arg0) {
// TODO Auto-generated method stub
mRequest.abort();
}
}