android - 使用 android-Asynctask 连接但仍然出现错误

Question

我正在尝试连接到一个 URL，以便我可以使用我的 PHP 文件进行 POST。当我执行这行代码时，我的 Android 应用程序不断崩溃并且不断出现错误:

OutputStream outputStream = httpURLConnection.getOutputStream();

这是我的代码，下面是我在 android studio 中遇到的错误。谢谢。

public class BackgroundWorker extends AsyncTask<String,Void,String> {
    Context context;
    AlertDialog alertDialog;
    BackgroundWorker (Context ctx) {
        context = ctx;
    }
    @Override
    protected String doInBackground(String... params) {
        String type = params[0];
        String login_url = "http://www.cs.csub.edu/~zobeid/Android/login.php";
        if(type.equals("login")) {
            try {
                String user_name = params[1];
                String password = params[2];
                URL url = new URL(login_url);
                HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outputStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
                String post_data = URLEncoder.encode("user_name","UTF-8")+"="+URLEncoder.encode(user_name,"UTF-8")+"&"
                        +URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8");
                bufferedWriter.write(post_data);
                bufferedWriter.flush();
                bufferedWriter.close();
                outputStream.close();
                InputStream inputStream = httpURLConnection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
                String result="";
                String line="";
                while((line = bufferedReader.readLine())!= null) {
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return result;
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

FATAL EXCEPTION: AsyncTask #1 Process: com.example.modernkill_laptop.mysqlproject, PID: 18789 java.lang.RuntimeException: An error occurred while executing doInBackground()

Answer 1

大家好，我找到了解决我的问题的方法，这正是我尝试连接所有内容的方法。因此，对于尝试连接到 PHPMySQL 数据库的任何人，请按照她提供的这个快速简单的教程进行操作。解决了我所有的问题。

http://androidcss.com/android/android-php-mysql-login-tutorial/