Java 该应用程序已停止运行

我试图用教程编写一个简单的登录页面。这是我的Java页面：

public class Main extends Activity implements OnClickListener{
    EditText etUser, etPass;
    Button bLogin;

    //Create string variables that will have the input assigned to them
    String username, password;

    //Create a HTTPClient as the form container
    HttpClient httpclient;

    //Use HTTP POST method
    HttpPost httppost;

    //Create an array list for the input data to be sent
    ArrayList<NameValuePair> nameValuePairs;

    //Create a HTTP Response and HTTP Entity
    HttpResponse response;
    HttpEntity entity;



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        initialise();
    }

    private void initialise() {
        // TODO Auto-generated method stub
        etUser = (EditText) findViewById(R.id.username);
        etPass = (EditText) findViewById(R.id.password);
        bLogin = (Button) findViewById(R.id.login_button);
        //Now to set an onClickListener
        bLogin.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        // This is where we will be working now

        //Create new default HTTPClient
        httpclient = new DefaultHttpClient();

        //Create new HTTP POST with URL to php file as parameter
        httppost = new HttpPost("http://10.0.2.2:8080/logine/work.php");

        //Assign input text to strings
        username = etUser.getText().toString();
        password = etPass.getText().toString();

        //place them in an array list
        nameValuePairs.add(new BasicNameValuePair("username", username));
        nameValuePairs.add(new BasicNameValuePair("password", password));

        //Next block of code needs to be surrounded by try/catch block for it to work
        try {
            //Add array list to http post
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

            //assign executed form container to response
            response = httpclient.execute(httppost);

            //check status code, need to check status code 200
            if(response.getStatusLine().getStatusCode()== 200){

                //assign response entity to http entity
                entity = response.getEntity();

                //check if entity is not null
                if(entity != null){


                    //Create new input stream with received data assigned
                    InputStream instream = entity.getContent();

                    //Create new JSON Object. assign converted data as parameter.
                    JSONObject jsonResponse = new JSONObject(convertStreamToString(instream));

                    //assign json responses to local strings
                    String retUser = jsonResponse.getString("user");//mySQL table field
                    String retPass = jsonResponse.getString("pass");

                }


            }


        } catch(Exception e){
            e.printStackTrace();
        }






    }//END onClick()

    private static String convertStreamToString(InputStream is) {
        /*
         * To convert the InputStream to String we use the BufferedReader.readLine()
         * method. We iterate until the BufferedReader return null which means
         * there's no more data to read. Each line will appended to a StringBuilder
         * and returned as String.
         */
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }//END convertStreamToString()

}

---

我做错了什么。就算我不太懂java。顺便说一句，我的AVD是2.3.3版的。你没有初始化对象

nameValuePairs

nameValuePairs = new ArrayList<NameValuePair>();

nameValuePairs=newArrayList（）；

您没有初始化对象

nameValuePairs

nameValuePairs = new ArrayList<NameValuePair>();

nameValuePairs=newArrayList（）；

您尚未初始化nameValuePairs

ArrayList<NameValuePair> nameValuePairs;

ArrayList nameValuePairs；

---

并且它有空值。

您还没有初始化nameValuePairs

ArrayList<NameValuePair> nameValuePairs;

ArrayList nameValuePairs；

---

并且它有空值。

-您只声明了

名称值对

类型的

对象引用数组列表

变量

名称值对

-在

类范围

中声明，其和

对象

的默认值为

null

---

-您必须初始化它..

-您只声明了

名称值对

类型的

对象引用数组列表

变量

名称值对

-在

类范围

中声明，其和

对象

的默认值为

null

---

-您必须初始化它..

com.Application.Main.onClick（Main.java:79）行是什么？它的nameValuePairs.add（新的BasicNameValuePair（“用户名”，username））；添加（新的BasicNameValuePair（“密码”，password））；什么是com.Application.Main.onClick（Main.java:79）？它的nameValuePairs.add（新的BasicNameValuePairs（“用户名”，用户名））；添加（新的BasicNameValuePair（“密码”，password））；我在一开始就初始化了它，我必须再做一次吗？如果必须的话，我应该把它放在哪里？它会获取etuser和et密码，但不会将它们传递到用户名中。你没有像nameValuePairs=new ArrayList（）这样的东西；我的用户名仍然是空的。我该怎么办？我在一开始就初始化了它，我必须再做一次吗。如果必须，我应该把它放在哪里？它正在获取etuser和et password，但它不会将它们传递到用户名中。你没有像nameValuePairs=new ArrayList（）这样的东西；我的用户名仍为空。我该怎么办？