Question

我现在已经和他一起战斗了6个小时。我已经关注了Dropbox的“教程”（如果它们可以被称为，因为它们非常差），使用DBRoulette示例，并完成了大量的工作以使我的应用程序正常工作。

我的应用可以毫无问题地进行身份验证。但是，尽管做了教程正在做的事情，我无法上传任何内容：

这是我的一小段代码（这是为了在手机上保存已创建的便笺，然后上传到Dropbox）：

        saveBtn.setOnClickListener(new OnClickListener()
    {
        @Override
        public void onClick(View view)
        {
            try
            {
                //Create the directory if it doesn't exist. If it does exist the next two line won't do anything.
                File dropNotesDir = new File(Environment.getExternalStorageDirectory() + "/documents/AppData/Dropnotes/");
                dropNotesDir.mkdirs();
                //-----------------------------------------------------------------------------------------------
                String wholeNoteString = noteBody.getText().toString();
                //Now we create the title of the txt file. It will be the first line of the whole note. The name will get truncated to 32 characters
                //if it's too long.
                String noteTitle;
                if(wholeNoteString.indexOf("\n") >= 0) //New line character found.
                {
                    noteTitle = wholeNoteString.substring(0, wholeNoteString.indexOf("\n"));
                    if(noteTitle.length() >= 32)
                    {
                        noteTitle = wholeNoteString.substring(0, 32);
                    }
                }
                else
                {
                    if(wholeNoteString.length() >= 32)
                    {
                        noteTitle = wholeNoteString.substring(0, 32);
                    }else
                    {
                        noteTitle = wholeNoteString;
                    }
                }
                if(extras.getString("file-mode").equals("modify"))
                {
                    //We will need to delete the existing file if it does exist to save the new one.
                    File existing = new File(Environment.getExternalStorageDirectory() + "/documents/AppData/Dropnotes/" + extras.getString("noteTitle"));
                    existing.delete();
                }
                File newNote = new File(Environment.getExternalStorageDirectory() + "/documents/AppData/Dropnotes/" + noteTitle + ".txt");
                PrintWriter newNoteWriter = new PrintWriter(new FileOutputStream(newNote));
                newNoteWriter.print(noteBody.getText().toString());
                newNoteWriter.close();

                //TRYING TO UPLOAD TO DROPBOX HERE
                File fileToUpload = new File(Environment.getExternalStorageDirectory() + "/documents/AppData/Dropnotes/" + noteTitle + ".txt");
                FileInputStream file2Uis = new FileInputStream(fileToUpload);
                Entry newEntry = mDBApi.putFile("/" + noteTitle + ".txt", file2Uis, fileToUpload.length(), null, null);
                //END OF TRYING TO UPLOAD TO DROPBOX HERE

                Toast.makeText(view.getContext(), "Saved successfully", Toast.LENGTH_SHORT).show();
                finish();
            } catch (FileNotFoundException e)
            {
                Toast.makeText(view.getContext(), "File not found: " + e.getMessage(), Toast.LENGTH_SHORT).show();
                e.printStackTrace();
            } catch(Exception e)
            {
                Toast.makeText(view.getContext(), "Some bizarre exception occured: " + e.getClass().toString(), Toast.LENGTH_SHORT).show();
                e.printStackTrace();
            }
        }

    });

它给了我一个NetworkOnMainThreadException，我不知道为什么。我正在尝试按照标题为“上传文件”的部分here进行操作。令他感到困惑的是他们的片段是他们甚至没有试图捕捉我被抛出的异常......

有任何帮助吗？我真的需要在下周五开始工作。

Answer 1

在Honeycomb SDK之前，允许在主线程上执行网络操作。但是，使用Honeycomb时，如果在主/ UI线程中尝试进行网络操作，则不再允许它并抛出NetworkOnMainThreadException。

您需要在不同的线程中执行网络操作。您可以查看AsyncTask以实现相同目标。

Answer 2

我的猜测是，StrictMode.ThreadPolicy引起的错误。您无法在同一UI线程中访问网络。

尝试将这些行添加到oncreate

中的代码中

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 
StrictMode.setThreadPolicy(policy);

试图上传到Dropbox：NetworkOnMainThreadException？

2 个答案: