我怎样才能得到 Json 响应

Question

她是我使用网络服务注册的代码，一切正常，但我不知道如何从网络服务获取 json 响应状态

Register.java

package com.example.limitscale.beautylog;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.*;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;
import org.json.JSONException;
import org.json.JSONObject;
import cz.msebera.android.httpclient.Header;

public class Register extends Activity {

private EditText editTextName;
private EditText editTextUsername;
private EditText editTextPassword;
private EditText editTextEmail;
private EditText editTextMobile;

private Button buttonRegister;

private static final String REGISTER_URL = "http://beauty.limitscale.com/webservices/register.php";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);

    editTextName = (EditText) findViewById(R.id.name);
    editTextUsername = (EditText) findViewById(R.id.username);
    editTextPassword = (EditText) findViewById(R.id.password);
    editTextEmail = (EditText) findViewById(R.id.email);
    editTextMobile = (EditText) findViewById(R.id.mobile);

    buttonRegister = (Button) findViewById(R.id.register);

    buttonRegister.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {



            String name=editTextName.getText().toString();
            String uname=editTextUsername.getText().toString();
            String password=editTextPassword.getText().toString();
            String email=editTextEmail.getText().toString();
            String mobile=editTextMobile.getText().toString();

            if(Utility.isNotNull(name) && Utility.isNotNull(email) && Utility.isNotNull(password)
                    && Utility.isNotNull(mobile) && Utility.isNotNull(uname)){
                // When Email entered is Valid
                registerUser();
                Intent intentSignUP = new Intent(Register.this, MainActivity.class);
                startActivity(intentSignUP);

                }
            else {
                Toast.makeText(getApplicationContext(), "Please enter valid email", Toast.LENGTH_LONG).show();
            }
        }
    });
}




private void registerUser() {
    String name = editTextName.getText().toString().trim().toLowerCase();
    String username = editTextUsername.getText().toString().trim().toLowerCase();
    String password = editTextPassword.getText().toString().trim().toLowerCase();
    String email = editTextEmail.getText().toString().trim().toLowerCase();
    String mobile = editTextMobile.getText().toString().trim().toLowerCase();

    register(name,username,password,email,mobile);
}

private void register(String name, String username, String password, String email,String mobile) {
    class RegisterUser extends AsyncTask<String, Void, String>{
        ProgressDialog loading;
        RegisterUserClass ruc = new RegisterUserClass();


        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            loading = ProgressDialog.show(Register.this, "Please Wait",null, true, true);
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            loading.dismiss();
            Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show();
        }

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

            HashMap<String, String> data = new HashMap<String,String>();
            data.put("name",params[0]);
            data.put("username",params[1]);
            data.put("password",params[2]);
            data.put("email",params[3]);
            data.put("mobile",params[4]);

            String result = ruc.sendPostRequest(REGISTER_URL,data);

            return  result;
        }
    }

    RegisterUser ru = new RegisterUser();
    ru.execute(name,username,password,email,mobile);
}}class RegisterUserClass {

public String sendPostRequest(String requestURL,
                              HashMap<String, String> postDataParams) {

    URL url;
    String response = "";
    try {
        url = new URL(requestURL);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setReadTimeout(15000);
        conn.setConnectTimeout(15000);
        conn.setRequestMethod("POST");
        conn.setDoInput(true);
        conn.setDoOutput(true);


        OutputStream os = conn.getOutputStream();
        BufferedWriter writer = new BufferedWriter(
                new OutputStreamWriter(os, "UTF-8"));
        writer.write(getPostDataString(postDataParams));

        writer.flush();
        writer.close();
        os.close();
        int responseCode=conn.getResponseCode();

        if (responseCode == HttpsURLConnection.HTTP_OK) {
            BufferedReader br=new BufferedReader(new InputStreamReader(conn.getInputStream()));
            response = br.readLine();
        }
        else {
            response="Error Registering";
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

    return response;
}

private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException {
    StringBuilder result = new StringBuilder();
    boolean first = true;
    for(Map.Entry<String, String> entry : params.entrySet()){
        if (first)
            first = false;
        else
            result.append("&");

        result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
        result.append("=");
        result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
    }

    return result.toString();
}}

当我点击注册按钮重定向到下一个活动时，即使正在显示用户已经存在的文本，它也会进入下一步，所以我只想在将 json 状态设为 true 时才重定向到下一个活动

Answer 1

这是因为您的代码结构如下：

registerUser();
 Intent intentSignUP = new Intent(Register.this, MainActivity.class);
 startActivity(intentSignUP);

这意味着无论结果如何，您的用户仍将被重定向到 MainActivity。

相反，如果 JSON 状态为 true，则应在 onPostExecute() 中完成重定向。否则，不要重定向并吐出错误消息。因此，请尝试按如下方式更新您的代码。

if(Utility.isNotNull(name) && Utility.isNotNull(email) && Utility.isNotNull(password)
                    && Utility.isNotNull(mobile) && Utility.isNotNull(uname)){
                // When Email entered is Valid
                registerUser();
                }

在你的 onPostExecute() 中，

@Override
          protected void onPostExecute(String s) {
                super.onPostExecute(s);
                loading.dismiss();
                //do your JSON status checking here.
Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show();
            }