Question

我目前正在处理我的登录活动，我的电子邮件验证遇到了麻烦。即使toast消息确实说“无效的电子邮件地址”，它仍然会转到下一个Activity而不是保留在LoginActivity中，直到它是有效的电子邮件地址。

这是我的LoginActivity.java

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.facebook.widget.LoginButton;
import com.wny.wecare.handler.JSONParser;


public class LoginActivity extends Activity implements OnClickListener {

    public final Pattern EMAIL_ADDRESS_PATTERN = Pattern.compile(
            "[a-zA-Z0-9+._%-+]{1,256}" +
                    "@" +
                    "[a-zA-Z0-9][a-zA-Z0-9-]{0,64}" +
                    "(" +
                    "." +
                    "[a-zA-Z0-9][a-zA-Z0-9-]{0,25}" +
                    ")+"
            );


    // Progress Dialog
    private ProgressDialog pDialog;

    JSONParser jsonParser = new JSONParser();
    EditText inputEmail;
    Button btnLogin;

    public String strUid;

    // url to create new user
    private static String url_create_user = "http://infinitycodeservices.com/create_user.php";


    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private LoginButton btnFacebookLogin;


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

        // Edit Text
        inputEmail = (EditText) findViewById(R.id.email);

        // Create button
        Button btnCreateUser = (Button) findViewById(R.id.btnEmail);

        // button click event
        btnCreateUser.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                String email=inputEmail.getText().toString();
                if(checkEmail(email))
                    Toast.makeText(LoginActivity.this,"Valid Email Addresss", Toast.LENGTH_SHORT).show();
                else
                    Toast.makeText(LoginActivity.this,"Invalid Email Addresss", Toast.LENGTH_SHORT).show();
                // creating new user in background thread
                new CreateNewUser().execute();
            }
        });
    }
    private boolean checkEmail(String email) {
        return EMAIL_ADDRESS_PATTERN.matcher(email).matches();
    }

    /**
     * Background Async Task to Create new User
     * */
    class CreateNewUser extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(LoginActivity.this);
            pDialog.setMessage("Logging In..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        /**
         * Creating User
         * */
        @Override
        protected String doInBackground(String... args) {
            // TODO Auto-generated method stub

            // Setup ArrayList from main activity to store results
            ArrayList<Map<String, String>> emailList = new ArrayList<Map<String,  String>>();

            String email = ((EditText) findViewById(R.id.email)).getText().toString().trim();

            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("Email", email));

            // Creating JSON Parser object
            JSONParser jParser = new JSONParser();

            // Getting JSON string from URL
            JSONArray json = jParser.getJSONFromUrl(url_create_user, params);

            for (int i = 0; i < json.length(); i++) {
                HashMap<String, String> map = new HashMap<String, String>();

                try {
                    JSONObject c = (JSONObject) json.get(i);
                    //Fill map
                    Iterator iter = c.keys();
                    while(iter.hasNext())   {
                        String currentKey = (String) iter.next();
                        map.put(currentKey, c.getString(currentKey));
                    }
                    emailList.add(map);

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

                }

            };

            //SAVE
            SharedPreferences ui = getSharedPreferences("UserInfo", MODE_PRIVATE);
            SharedPreferences.Editor edUi = ui.edit();
            edUi.putString("uid", strUid);
            edUi.putString("email", email);
            edUi.commit();

            startActivity(new Intent(LoginActivity.this, MainActivity.class));
            finish();

            // Returns Toast "Login success!"
            //return json.getString(TAG_MESSAGE);

            return null;

        }

        /**
         * After completing background task Dismiss the progress dialog
         * *
         */
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once product deleted
            pDialog.dismiss();
            if (file_url != null) {
                Toast.makeText(LoginActivity.this, file_url, Toast.LENGTH_LONG).show();
            }

        }

    }

    public void onClick(View v) {
        // TODO Auto-generated method stub

    }

}

Answer 1

在真实条件中执行你的asynctask

   if(checkEmail(email)) {
                        Toast.makeText(LoginActivity.this,"Valid Email Addresss", Toast.LENGTH_SHORT).show();
    // creating new user in background thread 
     new CreateNewUser().execute();
            }       
                else {
                        Toast.makeText(LoginActivity.this,"Invalid Email Addresss", Toast.LENGTH_SHORT).show();
      }

Answer 2

如果条件如下，你只需要将花括号括起来： -

        // button click event
            btnCreateUser.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View view) {
                    String email=inputEmail.getText().toString();
                    if(checkEmail(email)){
                        Toast.makeText(LoginActivity.this,"Valid Email Addresss",Toast.LENGTH_SHORT).show();

                      // creating new user in background thread
                      new CreateNewUser().execute();
                    }else{
                        Toast.makeText(LoginActivity.this,"Invalid Email Addresss", Toast.LENGTH_SHORT).show();


                    }
                }
            });

代码问题在于您每次都在执行异步任务。

如何阻止无效的电子邮件地址转到下一个活动

2 个答案: