Hello,

I need help with an assignment from murah's Android programming 2nd edition. It is chapter 6 example 3. We are supposed to modify the Tip Calculator app thats presented in the chapter so it uses anonymous inner classes for event listeners. I don't know how to do this though as I am not sure where it needs changed or how to. The EditText, SeekBar, RadioGroup, and Spinner listeners are what are supposed to be changed to being anonymous inner classes. Here is the code.

package com.murach.tipcalculator;

 import java.text.NumberFormat; import android.os.Bundle; import android.view.KeyEvent; import android.view.View; import android.view.View.OnKeyListener; import android.view.inputmethod.EditorInfo; import android.view.inputmethod.InputMethodManager; import android.widget.AdapterView; import android.widget.AdapterView.OnItemSelectedListener; import android.widget.ArrayAdapter; import android.widget.EditText; import android.widget.RadioButton; import android.widget.RadioGroup; import android.widget.RadioGroup.OnCheckedChangeListener; import android.widget.SeekBar; import android.widget.SeekBar.OnSeekBarChangeListener; import android.widget.Spinner; import android.widget.TextView; import android.widget.TextView.OnEditorActionListener; import android.app.Activity; import android.content.Context; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; public class TipCalculatorActivity extends Activity implements OnEditorActionListener, OnSeekBarChangeListener, OnCheckedChangeListener, OnItemSelectedListener, OnKeyListener { // define variables for the widgets  private EditText billAmountEditText; private TextView percentTextView; private SeekBar percentSeekBar; private TextView tipTextView; private TextView totalTextView; private RadioGroup roundingRadioGroup; private RadioButton roundNoneRadioButton; private RadioButton roundTipRadioButton; private RadioButton roundTotalRadioButton; private Spinner splitSpinner; private TextView perPersonLabel; private TextView perPersonTextView; // define the SharedPreferences object  private SharedPreferences savedValues; // define rounding constants  private final int ROUND_NONE = 0; private final int ROUND_TIP = 1; private final int ROUND_TOTAL = 2; // define instance variables  private String billAmountString = ""; private float tipPercent = .15f; private int rounding = ROUND_NONE; private int split = 1; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_tip_calculator); // get references to the widgets  billAmountEditText = (EditText) findViewById(R.id.billAmountEditText); percentTextView = (TextView) findViewById(R.id.percentTextView); percentSeekBar = (SeekBar) findViewById(R.id.percentSeekBar); tipTextView = (TextView) findViewById(R.id.tipTextView); totalTextView = (TextView) findViewById(R.id.totalTextView); roundingRadioGroup = (RadioGroup) findViewById(R.id.roundingRadioGroup); roundNoneRadioButton = (RadioButton) findViewById(R.id.roundNoneRadioButton); roundTipRadioButton = (RadioButton) findViewById(R.id.roundTipRadioButton); roundTotalRadioButton = (RadioButton) findViewById(R.id.roundTotalRadioButton); splitSpinner = (Spinner) findViewById(R.id.splitSpinner); perPersonLabel = (TextView) findViewById(R.id.perPersonLabel); perPersonTextView = (TextView) findViewById(R.id.perPersonTextView); // set array adapter for spinner  ArrayAdapter adapter = ArrayAdapter.createFromResource( this, R.array.split_array, android.R.layout.simple_spinner_item); adapter.setDropDownViewResource( android.R.layout.simple_spinner_dropdown_item); splitSpinner.setAdapter(adapter); // set the listeners  billAmountEditText.setOnEditorActionListener(this); billAmountEditText.setOnKeyListener(this); percentSeekBar.setOnSeekBarChangeListener(this); percentSeekBar.setOnKeyListener(this); roundingRadioGroup.setOnCheckedChangeListener(this); roundingRadioGroup.setOnKeyListener(this); splitSpinner.setOnItemSelectedListener(this); // get SharedPreferences object  savedValues = getSharedPreferences("SavedValues", MODE_PRIVATE); } @Override public void onPause() { // save the instance variables  Editor editor = savedValues.edit(); editor.putString("billAmountString", billAmountString); editor.putFloat("tipPercent", tipPercent); editor.putInt("rounding", rounding); editor.putInt("split", split); editor.commit(); super.onPause(); } @Override public void onResume() { super.onResume(); // get the instance variables  billAmountString = savedValues.getString("billAmountString", ""); tipPercent = savedValues.getFloat("tipPercent", 0.15f); rounding = savedValues.getInt("rounding", ROUND_NONE); split = savedValues.getInt("split", 1); // set the bill amount on its widget  billAmountEditText.setText(billAmountString); // set the tip percent on its widget  int progress = Math.round(tipPercent * 100); percentSeekBar.setProgress(progress); // set rounding on radio buttons  // NOTE: this executes the onCheckedChanged method,  // which executes the calculateAndDisplay method  if (rounding == ROUND_NONE) { roundNoneRadioButton.setChecked(true); } else if (rounding == ROUND_TIP) { roundTipRadioButton.setChecked(true); } else if (rounding == ROUND_TIP) { roundTotalRadioButton.setChecked(true); } // set split on spinner  // NOTE: this executes the onItemSelected method,  // which executes the calculateAndDisplay method  int position = split - 1; splitSpinner.setSelection(position); } public void calculateAndDisplay() { // get the bill amount  billAmountString = billAmountEditText.getText().toString(); float billAmount; if (billAmountString.equals("")) { billAmount = 0; } else { billAmount = Float.parseFloat(billAmountString); } // get tip percent  int progress = percentSeekBar.getProgress(); tipPercent = (float) progress / 100; // calculate tip and total  float tipAmount = 0; float totalAmount = 0; if (rounding == ROUND_NONE) { tipAmount = billAmount * tipPercent; totalAmount = billAmount + tipAmount; } else if (rounding == ROUND_TIP) { tipAmount = StrictMath.round(billAmount * tipPercent); totalAmount = billAmount + tipAmount; } else if (rounding == ROUND_TOTAL) { float tipNotRounded = billAmount * tipPercent; totalAmount = StrictMath.round(billAmount + tipNotRounded); tipAmount = totalAmount - billAmount; } // calculate split amount and show/hide split amount widgets  float splitAmount = 0; if (split == 1) { // no split - hide widgets  perPersonLabel.setVisibility(View.GONE); perPersonTextView.setVisibility(View.GONE); } else { // split - calculate amount and show widgets  splitAmount = totalAmount / split; perPersonLabel.setVisibility(View.VISIBLE); perPersonTextView.setVisibility(View.VISIBLE); } // display the results with formatting  NumberFormat currency = NumberFormat.getCurrencyInstance(); tipTextView.setText(currency.format(tipAmount)); totalTextView.setText(currency.format(totalAmount)); perPersonTextView.setText(currency.format(splitAmount)); NumberFormat percent = NumberFormat.getPercentInstance(); percentTextView.setText(percent.format(tipPercent)); } //*****************************************************  // Event handler for the EditText  //*****************************************************  @Override public boolean onEditorAction(TextView v, int actionId, KeyEvent event) { if (actionId == EditorInfo.IME_ACTION_DONE || actionId == EditorInfo.IME_ACTION_UNSPECIFIED) { calculateAndDisplay(); } return false; } //*****************************************************  // Event handler for the SeekBar  //*****************************************************  @Override public void onStartTrackingTouch(SeekBar seekBar) { // TODO Auto-generated method stub  } @Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { percentTextView.setText(progress + "%"); } @Override public void onStopTrackingTouch(SeekBar seekBar) { calculateAndDisplay(); } //*****************************************************  // Event handler for the RadioGroup  //*****************************************************  @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId) { case R.id.roundNoneRadioButton: rounding = ROUND_NONE; break; case R.id.roundTipRadioButton: rounding = ROUND_TIP; break; case R.id.roundTotalRadioButton: rounding = ROUND_TOTAL; break; } calculateAndDisplay(); } //*****************************************************  // Event handler for the Spinner  //*****************************************************  @Override public void onItemSelected(AdapterView parent, View v, int position, long id) { split = position + 1; calculateAndDisplay(); } @Override public void onNothingSelected(AdapterView parent) { // Do nothing  } //*****************************************************  // Event handler for the keyboard and DPad  //*****************************************************  @Override public boolean onKey(View view, int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_ENTER: case KeyEvent.KEYCODE_DPAD_CENTER: calculateAndDisplay(); // hide the soft keyboard  InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE); imm.hideSoftInputFromWindow( billAmountEditText.getWindowToken(), 0); // consume the event  return true; case KeyEvent.KEYCODE_DPAD_RIGHT: case KeyEvent.KEYCODE_DPAD_LEFT: if (view.getId() == R.id.percentSeekBar) { calculateAndDisplay(); } break; } // don't consume the event  return false; }