Edittext Nullwertüberprüfung in Android

Question

Hallo ich möchte Validierung in meinem Anmeldebildschirm. Ich habe zwei Edittext, wenn einige Null von ihnen als Code zeigen Fehler wie bitte geben Sie Benutzername und Passwort beim Login Button klicken.

dies ist mein erster Klasse activity_login.java

package com.ad_blinds.ad_bliends.ad_bliends; 

import android.app.ProgressDialog; 
import android.content.Intent; 
import android.content.SharedPreferences; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 

import org.json.JSONException; 
import org.json.JSONObject; 

import java.util.HashMap; 

/** 
* Created by jignesh on 20-07-2016. 
*/ 
public class activity_login extends AppCompatActivity implements View.OnClickListener { 

    public static final String USER_NAME =""; 
    public static final String PASSWORD=""; 
    private static final String LOGIN_URL = "http://www.techonlab.com/AdMobileApp/login.php"; 

    private EditText editTextUserName; 
    private EditText editTextPassword; 

    private Button buttonLogin; 

    @Override 
    protected void onCreate(@Nullable Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.login); 
     editTextUserName = (EditText) findViewById(R.id.Username); 
     editTextPassword = (EditText) findViewById(R.id.Password); 

     buttonLogin = (Button)findViewById(R.id.btnLogin); 
     buttonLogin.setOnClickListener(this); 

    } 


    private void login() { 

     String username = editTextUserName.getText().toString().trim(); 
     String password = editTextPassword.getText().toString().trim(); 
     userLogin(username, password); 

    } 

    private void userLogin(String username, String password) { 
     class UserLoginClass extends AsyncTask<String, Void, String> { 

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

      @Override 
      protected void onPostExecute(String s) { 
       super.onPostExecute(s); 
       loading.dismiss(); 
       String jsonValue=s; 

       try { 
        JSONObject jsonReplay = new JSONObject(jsonValue); 
        JSONObject userDetail = jsonReplay.getJSONObject("user_details"); 

        String USER_ID = userDetail.getString("user_id"); 
        String USER_NAME = userDetail.getString("user_name"); 
        String SUCCESS = userDetail.getString("Success"); 

        if(SUCCESS=="1") 
        { 
         SharedPreferences sp=getSharedPreferences("Login",0); 
         SharedPreferences.Editor Ed=sp.edit(); 
         Ed.putString("USER_ID",USER_ID); 
         Ed.putString("USER_NAME",USER_NAME); 
         Ed.putString("LOGIN",SUCCESS); 
         Ed.commit(); 

         Toast.makeText(activity_login.this, "Wel-come "+USER_NAME, Toast.LENGTH_SHORT).show(); 
         Intent intent = new Intent(activity_login.this,activity_home.class); 
         startActivity(intent); 
        } 

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

      @Override 
      protected String doInBackground(String... params) { 
       HashMap<String, String> data = new HashMap<>(); 
       data.put("username", params[0]); 
       data.put("password", params[1]); 

       RegisterUserClass ruc = new RegisterUserClass(); 
       String result = ruc.sendPostRequest(LOGIN_URL, data); 
       return result; 
      } 

     } 
     UserLoginClass ulc = new UserLoginClass(); 
     ulc.execute(username,password); 
    } 


    @Override 
    public void onClick(View v) { 
     if(v == buttonLogin) { 
      login(); 
     } 
    } 
} 

Dieser Name meiner zweiten Klasse ist regsteruserclass.java ist

package com.ad_blinds.ad_bliends.ad_bliends; 

import java.io.BufferedReader; 
import java.io.BufferedWriter; 
import java.io.InputStreamReader; 
import java.io.OutputStream; 
import java.io.OutputStreamWriter; 
import java.io.UnsupportedEncodingException; 
import java.net.HttpURLConnection; 
import java.net.URL; 
import java.net.URLEncoder; 
import java.util.HashMap; 
import java.util.Map; 

import javax.net.ssl.HttpsURLConnection; 

/** 
* Created by Belal on 8/6/2015. 
*/ 
public 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"; 
      } 
     } 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(); 
    } 
} 

Answer 1

Ändern Sie Ihren Code unten zu zeigen, Validierung:

private void login() { 

    String username = editTextUserName.getText().toString().trim(); 
    String password = editTextPassword.getText().toString().trim(); 

    if (username.equals("")) { 
     Toast.makeText(this, "Please enter username",    Toast.LENGTH_SHORT).show(); 
    } 
    else if (password.equals("")) { 
     Toast.makeText(this, "Please enter password", Toast.LENGTH_SHORT).show(); 
    } 
    else{ 
    userLogin(username, password); 
} 

}