I used some sample codes and tried to build up a login screen with a username and password for an android app. However, I am getting the following errors \[code\]"XYZ cannot be resolved or is not a field"\[/code\].In my program, the \[code\]XYZ's\[/code\] are the: \[code\]tv\[/code\] and \[code\]btn_ok\[/code\] fields in the the \[code\]loginerror.java\[/code\] file, and \[code\]btn_sign_in\[/code\], \[code\]txt_username\[/code\], \[code\]txt_password\[/code\] in the \[code\]loginactivity.java\[/code\] file.This is my code for \[code\]loginerror.java\[/code\]... \[code\] public class LoginError extends Activity { Button button; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); System.gc(); setContentView(R.layout.LoginError); TextView textview = (TextView) findViewById(R.id.tv); String loginMessage = getIntent().getStringExtra("LoginMessage"); textview.setText(loginMessage); button = (Button) findViewById(R.id.btn_ok); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { finish(); } }); } }>\[/code\]This is my code for \[code\]loginactivity.java\[/code\]... \[code\] import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP; import org.xml.sax.InputSource; import org.xml.sax.XMLReader; public class LoginActivity extends Activity { /** Called when the activity is first created. */ private static final String TAG = "Login"; Button signin; String loginmessage = null; Thread t; private SharedPreferences mPreferences; ProgressDialog dialog; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mPreferences = getSharedPreferences("CurrentUser", MODE_PRIVATE); if (!checkLoginInfo()) { signin = (Button) findViewById(R.id.btn_sign_in); signin.setOnClickListener(new OnClickListener() { public void onClick(View v) { showDialog(0); t=new Thread() { public void run() { tryLogin(); } }; t.start(); } }); } else { /*Directly opens the Welcome page, if the username and password is already available in the SharedPreferences*/ Intent intent=new Intent(getApplicationContext(),Welcome.class); startActivity(intent); finish(); } } protected Dialog onCreateDialog(int id) { switch (id) { case 0: { dialog = new ProgressDialog(this); dialog.setMessage("Speek is loading"); dialog.setIndeterminate(true); dialog.setCancelable(true); return dialog; } } return null; } private Handler handler = new Handler() { public void handleMessage(Message msg) { String loginmsg=(String)msg.obj; if(loginmsg.equals("SUCCESS")) { removeDialog(0); Intent intent=new Intent(getApplicationContext(),Welcome.class); startActivity(intent); finish(); } } }; public void tryLogin() { Log.v(TAG, "Trying to Login"); EditText etxt_user = (EditText) findViewById(R.id.txt_username); EditText etxt_pass = (EditText) findViewById(R.id.txt_password); String username = etxt_user.getText().toString(); String password = etxt_pass.getText().toString(); DefaultHttpClient client = new DefaultHttpClient(); HttpPost httppost = new HttpPost("http://www.speek.com"); List nvps = new ArrayList(); nvps.add(new BasicNameValuePair("username", username)); nvps.add(new BasicNameValuePair("password", password)); try { UrlEncodedFormEntity p_entity = new UrlEncodedFormEntity(nvps, HTTP.UTF_8); httppost.setEntity(p_entity); HttpResponse response = client.execute(httppost); Log.v(TAG, response.getStatusLine().toString()); HttpEntity responseEntity = response.getEntity(); Log.v(TAG, "Set response to responseEntity"); SAXParserFactory spf = SAXParserFactory.newInstance(); SAXParser sp = spf.newSAXParser(); XMLReader xr = sp.getXMLReader(); LoginHandler myLoginHandler = new LoginHandler(); xr.setContentHandler(myLoginHandler); xr.parse(retrieveInputStream(responseEntity)); ParsedLoginDataSet parsedLoginDataSet = myLoginHandler.getParsedLoginData(); if (parsedLoginDataSet.getExtractedString().equals("SUCCESS")) { // Store the username and password in SharedPreferences after the successful login SharedPreferences.Editor editor=mPreferences.edit(); editor.putString("UserName", username); editor.putString("PassWord", password); editor.commit(); Message myMessage=new Message(); myMessage.obj="SUCCESS"; handler.sendMessage(myMessage); } else if(parsedLoginDataSet.getExtractedString().equals("ERROR")) { Intent intent = new Intent(getApplicationContext(), LoginError.class); intent.putExtra("LoginMessage", parsedLoginDataSet.getMessage()); startActivity(intent); removeDialog(0); } } catch (Exception e) { Intent intent = new Intent(getApplicationContext(), LoginError.class); intent.putExtra("LoginMessage", "Unable to login"); startActivity(intent); removeDialog(0); } } private InputSource retrieveInputStream(HttpEntity httpEntity) { InputSource insrc = http://stackoverflow.com/questions/10805397/null; try { insrc = new InputSource(httpEntity.getContent()); } catch (Exception e) { } return insrc; } //Checking whether the username and password has stored already or not private final boolean checkLoginInfo() { boolean username_set = mPreferences.contains("UserName"); boolean password_set = mPreferences.contains("PassWord"); if ( username_set || password_set ) { return true; } return false; } }\[/code\]This is my \[code\]main.xml\[/code\]...\[code\]<?xml version="1.0" encoding="utf-8"?><AbsoluteLayout android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" > <Button android:id="@+id/btn_sign_in" android:layout_width="100dp" android:layout_height="wrap_content" android:text="Sign In" android:layout_x="103dp" android:layout_y="197dp"/> <EditText android:id="@+id/txt_username" android:layout_width="250dp" android:layout_height="wrap_content" android:hint="Username" android:singleLine="true" android:textSize="18sp" android:layout_x="40dp" android:layout_y="32dp" /> <EditText android:id="@+id/txt_password" android:layout_width="250dp" android:layout_height="wrap_content" android:hint="Password" android:singleLine="true" android:textSize="18sp" android
assword="true" android:layout_x="40dp" android:layout_y="86dp" /></AbsoluteLayout>\[/code\]This is my \[code\]loginerror.xml\[/code\] file...\[code\] <?xml version="1.0" encoding="utf-8"?> <AbsoluteLayout android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" > <TextView android:id="@+id/tv" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal"/> <Button android:id="@+id/btn_ok" android:layout_width="80dp" android:layout_height="wrap_content" android:text="OK" android:layout_x="83dp" android:layout_y="60dp" /> </AbsoluteLayout>\[/code\]The error is occurring at these lines...\[code\]1. TextView textview = (TextView) findViewById(R.id.tv);2. button = (Button) findViewById(R.id.btn_ok);3. signin = (Button) findViewById(R.id.btn_sign_in);4. EditText etxt_user = (EditText) findViewById(R.id.txt_username); EditText etxt_pass = (EditText) findViewById(R.id.txt_password);\[/code\]Do i have to add anything in the main program to fix this problem? What does the problem mean?
assword="true" android:layout_x="40dp" android:layout_y="86dp" /></AbsoluteLayout>\[/code\]This is my \[code\]loginerror.xml\[/code\] file...\[code\] <?xml version="1.0" encoding="utf-8"?> <AbsoluteLayout android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" > <TextView android:id="@+id/tv" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal"/> <Button android:id="@+id/btn_ok" android:layout_width="80dp" android:layout_height="wrap_content" android:text="OK" android:layout_x="83dp" android:layout_y="60dp" /> </AbsoluteLayout>\[/code\]The error is occurring at these lines...\[code\]1. TextView textview = (TextView) findViewById(R.id.tv);2. button = (Button) findViewById(R.id.btn_ok);3. signin = (Button) findViewById(R.id.btn_sign_in);4. EditText etxt_user = (EditText) findViewById(R.id.txt_username); EditText etxt_pass = (EditText) findViewById(R.id.txt_password);\[/code\]Do i have to add anything in the main program to fix this problem? What does the problem mean?