<uses-permission android:name="android.permission.INTERNET"></uses-permission>

private ProgressDialog pdialog;
    JSONParser jsonparser=new JSONParser();
    private String url_login="http://10.3.8.88/servercode/loginprocess.php";
    String username,password;


btnlogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                username=tusername.getText().toString();
                password=tpassword.getText().toString();
                if(username.length()==0 || password.length()==0)
                {
                    loginerror.setText("Invalid Details");
                    loginerror.setTextColor(Color.RED);
                    loginerror.setGravity(Gravity.CENTER_HORIZONTAL);
                }
                else
                {
                    new getlogindetails().execute();
                }
            }
        });

 class getlogindetails extends AsyncTask<String,String,String>
    {
        protected void onPreExecute()
        {
            super.onPreExecute();
            pdialog=new ProgressDialog(loginactivity.this);
            pdialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
            pdialog.setMessage("Logging in. Please wait...");
            pdialog.setIndeterminate(false);
            pdialog.setCancelable(true);
            pdialog.show();
        }
        @Override
        protected String doInBackground(String... params)
        {
            int success;
            try
            {
                Uri.Builder builder=new Uri.Builder()
                        .appendQueryParameter("username",username)
                        .appendQueryParameter("password",password);
                String query=builder.build().getEncodedQuery();
                JSONObject json=jsonparser.makeHttpRequest(url_login,query);
                if(json!=null)
                {
                    success=json.getInt("result");
                    if(success==1)
                    {
                        Intent menuintent=new Intent(getApplicationContext(),menuactivity.class);
                        startActivity(menuintent);
                    }
                    else
                    {
                        loginactivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                loginerror.setText("User not found !");
                                loginerror.setTextColor(Color.RED);
                            }
                        });
                    }
                }
                else
                {
                    loginactivity.this.runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            loginerror.setText("Unable to contact server !");
                            loginerror.setTextColor(Color.RED);
                        }
                    });
                }
            }
            catch(JSONException e)
            {
                e.printStackTrace();
            }
            return null;
        }
        protected void onPostExecute(String s)
        {
            pdialog.dismiss();
        }
    }