Android development: "R cannot be resolved", but in only one context within the class

I'm following along fairly closely in my code with Lauren Darcy's Teach Yourself Android Application Development in 24 Hours. I've hit a snag with "R cannot be resolved." on one line:

final View layout=inflater.inflate(R.layout.password_dialog, (ViewGroup) findViewById(R.id.root));

The "R cannot be resolved" shows up on this line twice, once for each reference to R.

• if I copy and paste the author's code, I get the same result, so it's not a typo
• from reading posts of others who have encountered this same issue, it sounds like R is not resolved anywhere in the class. However, I do use R in other contexts in this class without any objection and with expected results.
• another common piece of advice is to verify that I'm not importing android.R. I'm not.

At wit's end here... where should I be looking?

The class in full:

package com.oneinfinity.btdt;

import java.util.Calendar;


import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.text.format.Time;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android开发者_运维问答.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class QuizSettingsActivity extends QuizActivity {
    SharedPreferences mGameSettings;
    static final int DATE_DIALOG_ID=0;
    static final int PASSWORD_DIALOG_ID=1;


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.settings);
        mGameSettings=getSharedPreferences(GAME_PREFERENCES, MODE_PRIVATE);
        initTextField(R.id.etNickname, GAME_PREFERENCES_NICKNAME);
        initTextField(R.id.etEmail, GAME_PREFERENCES_EMAIL);
        writeBirthday();
        Button setPass=(Button) findViewById(R.id.ButtonPassword);
        Button setBd=(Button) findViewById(R.id.ButtonBirthday);
        setPass.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                //TODO - password dialog
                Toast.makeText(QuizSettingsActivity.this, "TODO: Password form", Toast.LENGTH_LONG).show();
            }
        });
        setBd.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                //TODO - birthday dialog
                //Toast.makeText(QuizSettingsActivity.this, "TODO: birthday form", Toast.LENGTH_LONG).show();
                showDialog(DATE_DIALOG_ID);
            }
        });
        setSpinner(R.id.spinnerGender, R.array.genderSet, GAME_PREFERENCES_GENDER);
    }

    private void setSpinner(int whichSpinner, int whichArray, String whichPref) {
        final String PutString=whichPref;
        final Spinner spinner=(Spinner) findViewById(whichSpinner);
        ArrayAdapter<?> adapter=ArrayAdapter.createFromResource(this, whichArray, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        if(mGameSettings.contains(PutString)) {
            int toSelect=mGameSettings.getInt(PutString, 0);
            spinner.setSelection(toSelect);
        }
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                public void onItemSelected(AdapterView<?> parent, View itemSelected, int selectedItemPosition, long selectedId) {
                    Editor editor = mGameSettings.edit();
                    editor.putInt(PutString, selectedItemPosition);
                    editor.commit();
                    //test whether committed
                    if(mGameSettings.contains(PutString)) {
                        Log.i("trace", "gender is set to " + mGameSettings.getInt(PutString, 0)+"");                
                    }
                    else {
                        Log.i("trace", "gender has not been specied yet");
                    }
                }
                public void onNothingSelected(AdapterView<?> parent) {
                    Toast.makeText(QuizSettingsActivity.this, "TODO:handle nothing selected", Toast.LENGTH_LONG).show();
                }
            });
    }


    private void initTextField(int whichField, String whichSetting) {
        final String PutSetting=whichSetting;
        final EditText findField=(EditText) findViewById(whichField);
        if(mGameSettings.contains(PutSetting)) {
            String textString=mGameSettings.getString(PutSetting, "");
            findField.setText(textString);
        }
        findField.setOnKeyListener(new View.OnKeyListener() {
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if((event.getAction()==KeyEvent.ACTION_DOWN) && (keyCode==KeyEvent.KEYCODE_ENTER)) {
                    String strValueToSave=findField.getText().toString();
                    Editor editor = mGameSettings.edit();
                    editor.putString(PutSetting, strValueToSave);
                    editor.commit();
                    return true;
                }
                return false;
            }
        });

    }

    /* Just in case it really is necessary to repeat these instructions
    private void initnicknameEntry() {
        final EditText nicknameText=(EditText) findViewById(R.id.etNickname);
        nicknameText.setOnKeyListener(new View.OnKeyListener() {
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if((event.getAction()==KeyEvent.ACTION_DOWN) && (keyCode==KeyEvent.KEYCODE_ENTER)) {
                    String strValueToSave=nicknameText.getText().toString();
                    return true;
                }
                return false;
            }
        });
    }
    */

    @Override
    protected Dialog onCreateDialog(int id) {
        switch(id) {
            case DATE_DIALOG_ID:
                DatePickerDialog dateDialog = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() { 
                    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) { 
                        TextView dob=(TextView) findViewById(R.id.TextView_Bday_Info);
                        Time dateOfBirth=new Time();
                        dateOfBirth.set(dayOfMonth, monthOfYear, year);
                        long dtDob = dateOfBirth.toMillis(true);
                        dob.setText(DateFormat.format("MMMM dd, yyyy", dtDob));
                        Editor editor=mGameSettings.edit();
                        editor.putLong(GAME_PREFERENCES_DOB, dtDob);
                        editor.commit();

                    }
                }, 0, 0, 0 );
            return dateDialog;
            case PASSWORD_DIALOG_ID:
                //create the dialog
                LayoutInflater inflater=(LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                final View layout=inflater.inflate(R.layout.password_dialog, (ViewGroup) findViewById(R.id.root));
                //return the dialog;
        }
        return null;
    }

    @Override 
    protected void onPrepareDialog(int id, Dialog dialog) {
        switch(id) {
        case DATE_DIALOG_ID:
            DatePickerDialog dateDialog = (DatePickerDialog) dialog;
            int iDay, iMonth, iYear;
            if(mGameSettings.contains(GAME_PREFERENCES_DOB)) {
                long bd=mGameSettings.getLong(GAME_PREFERENCES_DOB, 0);
                Time birthday=new Time();
                birthday.set(bd);
                iDay=birthday.monthDay;
                iMonth=birthday.month;
                iYear=birthday.year;
                Log.i("trace", "verifying that it is no longer the year 2");
            }
            else {
                Calendar cal=Calendar.getInstance();
                iDay=cal.get(Calendar.DAY_OF_MONTH);
                iMonth=cal.get(Calendar.MONTH);
                iYear=cal.get(Calendar.YEAR);
            }
            dateDialog.updateDate(iYear, iMonth, iDay);
            return;
        case PASSWORD_DIALOG_ID:
            //prepare the dialog
            return;         
        }
    }

    private void writeBirthday() {
        TextView dob=(TextView) findViewById(R.id.TextView_Bday_Info);
        CharSequence myBirthday=getResources().getString(R.string.no_birthday);
        if(mGameSettings.contains(GAME_PREFERENCES_DOB)) {
            long bd=mGameSettings.getLong(GAME_PREFERENCES_DOB, 0);
            myBirthday=DateFormat.format("MMMM dd, yyyy", bd);
        }
        dob.setText(myBirthday);
    }
}

Try going to Project -> Clean, run that. Then go to Project -> Build Project. You may need to uncheck "Build Automatically" first.

I would take Janus advice and remove imports Android.R; but replace with your.package.name.R; and will fix. =)

I can see two things a novice can fail in :

1. the xxx.xml is no lower case.
2. when you needed to write the sdk version what did you typed ?see this notice for the api level part

i have had some of these problems sometimes when i started with android. What i did was definitely check my imports. Should be, like they say, your_package_name.R and not Android.

Allso check if you manifest is good. And what works most of the time, its just simply restart Android Studio.

Good luck mate!