如何从Android HTTP post请求获取String？ [英] How to get a String from Android HTTP post request?

问题描述

我正在向网络服务器发送 HTTP post 请求登录。它返回字符串值 true 或 false 。
AsyncTask 代码：

I am sending HTTP post request to a web server for login.It returns string value true or false. AsyncTask code :

    class SendPostReqAsyncTask extends AsyncTask<String, Void, String>{
    HttpResponse httpResponse;
    @Override
    protected String doInBackground(String... params) {

        String paramUsername = params[0];
        String paramPassword = params[1];


        HttpClient httpClient = new DefaultHttpClient();

        HttpPost httpPost = new HttpPost("myurl");

        try {


        BasicNameValuePair usernameBasicNameValuePair = new BasicNameValuePair("user", paramUsername);
        BasicNameValuePair passwordBasicNameValuePAir = new BasicNameValuePair("password", paramPassword);


        List<NameValuePair> nameValuePairList = new ArrayList<NameValuePair>();
        nameValuePairList.add(usernameBasicNameValuePair);
        nameValuePairList.add(passwordBasicNameValuePAir);


            UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(nameValuePairList);

            httpPost.setEntity(urlEncodedFormEntity);
            httpResponse = httpClient.execute(httpPost);


            } catch (ClientProtocolException cpe) {
                System.out.println("First Exception caz of HttpResponese :" + cpe);

            } catch (IOException ioe) {
                System.out.println("Second Exception caz of HttpResponse :" + ioe);

            }




        return httpResponse.toString();
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);

        String s="true";
        if(result.equalsIgnoreCase(s)){
            Toast.makeText(getApplicationContext(), "Congrats! Login Successful...", Toast.LENGTH_LONG).show();
            Intent intent = new Intent(SignIn.this, Dashboard.class);
            startActivity(intent);


        }else{
            Toast.makeText(getApplicationContext(), "Invalid Username or Password...", Toast.LENGTH_LONG).show();
        }
    }
}

OnCreate 代码：

   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sign_in);
    editTextUserName = (EditText) findViewById(R.id.editTextUserNameToLogin);
    editTextPassword = (EditText) findViewById(R.id.editTextPasswordToLogin);

    Button btnSignIn = (Button) findViewById(R.id.buttonSignIn);
    // btnSignIn.setOnClickListener(this);
    btnSignIn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            //if (v.getId() == R.id.buttonSignIn) {
                String givenUsername = editTextUserName.getEditableText().toString();
                String givenPassword = editTextPassword.getEditableText().toString();

           //     System.out.println("Given username :" + givenUsername + " Given password :" + givenPassword);
            new SendPostReqAsyncTask().execute(givenUsername, givenPassword); } }); }

将 doInBackground 的返回值更改为 httpResponse.toString（）也会导致应用崩溃。
我是Android的新手，即使经过多次搜索，似乎无法弄清楚问题。任何帮助都表示赞赏。

Changing the return value of doInBackground to httpResponse.toString() also causes the app to crash. I am new to Android, and can't seem to figure out the problem even after much searching. Any help is appreciated.

编辑：httpResponse可以通过执行以下操作转换为字符串：

The httpResponse can be converted to string by doing the following :

String response = EntityUtils.toString(httpResponse.getEntity());

推荐答案

首先将HTTPResponse转换为字符串。

First Covert your HTTPResponse to String.

class SendPostReqAsyncTask extends AsyncTask<String, Void, String>{

    HttpResponse httpResponse;
    String result 

    @Override
    protected String doInBackground(String... params) {

        String paramUsername = params[0];
        String paramPassword = params[1];

     try {

        HttpClient httpClient = new DefaultHttpClient();

        HttpPost httpPost = new HttpPost("Your URL");
        BasicNameValuePair usernameBasicNameValuePair = new BasicNameValuePair("user", paramUsername);
        BasicNameValuePair passwordBasicNameValuePAir = new BasicNameValuePair("password", paramPassword);

        List<NameValuePair> nameValuePairList = new ArrayList<NameValuePair>();
        nameValuePairList.add(usernameBasicNameValuePair);
        nameValuePairList.add(passwordBasicNameValuePAir);

        UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(nameValuePairList);

        httpPost.setEntity(urlEncodedFormEntity);
        httpResponse = httpClient.execute(httpPost);

        //From here to Convert from HTTPResponse to String
        result= EntityUtils.toString(httpResponse.getEntity());

        } catch (ClientProtocolException cpe) {
            System.out.println("First Exception caz of HttpResponese :" + cpe);

        } catch (IOException ioe) {
            System.out.println("Second Exception caz of HttpResponse :" + ioe);

        }
 return result;
}

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