I have a SignUp function, called when a button is clicked. In the onClickListener function, it is called like this:
SignUp(Uname.getText().toString(), Pword.getText().toString(),
        Umail.getText().toString());                     
While the function is running, I need to show a progress bar. How can I do this?
Here is the code for the SignUp() function:
public void  SignUp (String Username, String Password, String Email) {
    Integer Userch = CheckUName (Username);
    Integer UserMl = CheckUMail (Email);
    if (Userch == 3)
    {
        Toast.makeText(getActivity(), "این نام کاربری قبلا ثبت شده است",
                Toast.LENGTH_LONG).show();      
    }
    else if (UserMl == 3)
       {
            Toast.makeText(getActivity(), "این پست الکترونیکی قبلا ثبت شده است", Toast.LENGTH_LONG).show();     
       }
       else if ((UserMl == 4) && (Userch == 4))
       {
                String Pass = null;
                InputStream is = null;
                String result = "";
                ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
                nameValuePairs.add(new BasicNameValuePair("UUName", Username));
                nameValuePairs.add(new BasicNameValuePair("UPWord", Password));
                nameValuePairs.add(new BasicNameValuePair("UMail", Email));
                try{
                        HttpClient httpclient = new DefaultHttpClient();
                        HttpPost httppost = new HttpPost(SignupAddress);
                        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
                        HttpResponse response = httpclient.execute(httppost);
                        HttpEntity entity = response.getEntity();
                        is = entity.getContent();
                        Toast.makeText(getActivity(), "ثبت نام انجام شد", Toast.LENGTH_LONG).show();        
                }catch(Exception e){
                    Log.e("log_tag", "Error in http connection "+e.toString());
                } 
       }
    }   
edited for libin : how i call :
 public void onClick(View v)
            {
                mProgressDialog.show();
                StrictMode.setThreadPolicy(policy); 
                String Result = login(Username.getText().toString());
                if (Username.getText().toString().equals(""))
                {
                    Toast.makeText(getActivity(), "نام کاربری را وارد کنید", Toast.LENGTH_SHORT).show();
                    mProgressDialog.hide();
                }
                else if  (Password.getText().toString().equals(""))
                {
                    Toast.makeText(getActivity(), "کلمه عبور را وارد کنید", Toast.LENGTH_SHORT).show();     
                    mProgressDialog.hide();
                }
                else
                {
                        if (Result.equals(Password.getText().toString()))
                         {
                            Intent i = new Intent(getActivity(), HomePage.class);
                             i.putExtra("new_variable_name",Username.getText().toString());
                             startActivity(i);
                         }
                         else if (Result == "Wrong Username or Password")
                         {
                            mProgressDialog.hide();
                              Toast.makeText(getActivity(), "نام کاربری یا کلمه عبور اشتباه است", Toast.LENGTH_SHORT).show();       
                         }
                          else if (Result == "Error Connection")
                         {
                            mProgressDialog.hide();
                              Toast.makeText(getActivity(), "مشکلی در برقراری ارتباط وجود دارد", Toast.LENGTH_SHORT).show();        
                         }
                          else if (Result == "Convert Error")
                         {
                            mProgressDialog.hide();
                              Toast.makeText(getActivity(), "مشکلی بوجود آمده است", Toast.LENGTH_SHORT).show();     
                         }
                          else 
                         {
                            mProgressDialog.hide();
                              Toast.makeText(getActivity(), "نام کاربری یا کلمه عبور اشتباه است", Toast.LENGTH_SHORT).show();       
                          }
                    }
            }
        });
 
    