Exercise 8-4 Use an EditTextPreference element In this exercise, you’ll modify t

Question

Exercise 8-4 Use an EditTextPreference element In this exercise, you’ll modify the Tip Calculator app presented in this chapter so it uses an EditTextPreference element. Although this type of preference wasn’t described in this chapter, it works similarly to the CheckBoxPreference element, and you can look it up in the documentation for the API if necessary. When you’re done, a test run should look like this:

Sorry can’t get the picture to show up. If you run it before changes you will see what it looks like except it needs the fifth row with a name label and they it needs to display a name as outlined in step 3.

1. Start Android Studio and open the project named ch08_ex4_TipCalculator. 1. Open the preferences.xml file in the xml directory. Add an EditTextPreference element for a setting named Name. This setting should allow the user to enter his or her full name.

2. Run the app and use the Settings activity to enter your name.

3. Open the layout of the activity. Modify the layout, so it includes a fifth row that can display a name. Open the class for the Tip Calculator activity. Modify this code so it gets the name from the preferences and displays that name in t

package com.murach.tipcalculator;

import java.text.NumberFormat;

import android.os.Bundle;

import android.preference.PreferenceManager;

import android.view.KeyEvent;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.inputmethod.EditorInfo;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.TextView.OnEditorActionListener;

import android.app.Activity;

import android.content.Intent;

import android.content.SharedPreferences;

import android.content.SharedPreferences.Editor;

public class TipCalculatorActivity extends Activity

implements OnEditorActionListener, OnClickListener {

    // define variables for the widgets

    private EditText billAmountEditText;

    private TextView percentTextView;  

    private Button   percentUpButton;

    private Button   percentDownButton;

    private TextView tipTextView;

    private TextView totalTextView;

   

    // define instance variables that should be saved

    private String billAmountString = "";

    private float tipPercent = .15f;

   

    // define rounding constants

    private final int ROUND_NONE = 0;

    private final int ROUND_TIP = 1;

    private final int ROUND_TOTAL = 2;

   

    // set up preferences

    private SharedPreferences prefs;

    private boolean rememberTipPercent = true;

    private int rounding = ROUND_NONE;

   

    @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);

        percentUpButton = (Button) findViewById(R.id.percentUpButton);

        percentDownButton = (Button) findViewById(R.id.percentDownButton);

        tipTextView = (TextView) findViewById(R.id.tipTextView);

        totalTextView = (TextView) findViewById(R.id.totalTextView);

        // set the listeners

        billAmountEditText.setOnEditorActionListener(this);

        percentUpButton.setOnClickListener(this);

        percentDownButton.setOnClickListener(this);

       

        // set the default values for the preferences

        PreferenceManager.setDefaultValues(this, R.xml.preferences, false);

       

        // get default SharedPreferences object

        prefs = PreferenceManager.getDefaultSharedPreferences(this);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.activity_tip_calculator, menu);

        return true;

    }

   

    @Override

   public void onPause() {

        // save the instance variables      

        Editor editor = prefs.edit();       

        editor.putString("billAmountString", billAmountString);

        editor.putFloat("tipPercent", tipPercent);

        editor.commit();       

        super.onPause();     

    }

   

    @Override

    public void onResume() {

        super.onResume();

       

        // get preferences

        rememberTipPercent = prefs.getBoolean("pref_remember_percent", true);

        rounding = Integer.parseInt(prefs.getString("pref_rounding", "0"));

        // get the instance variables

        billAmountString = prefs.getString("billAmountString", "");

        if (rememberTipPercent) {

            tipPercent = prefs.getFloat("tipPercent", 0.15f);

        } else {

            tipPercent = 0.15f;

        }

        // set the bill amount on its widget

        billAmountEditText.setText(billAmountString);

       

        // calculate and display

        calculateAndDisplay();

    }

   

    public void calculateAndDisplay() {       

        // get the bill amount

        billAmountString = billAmountEditText.getText().toString();

        float billAmount;

        if (billAmountString.equals("")) {

            billAmount = 0;

        }

        else {

            billAmount = Float.parseFloat(billAmountString);

        }

       

        // calculate tip and total

        float tipAmount = 0;

        float totalAmount = 0;

        float tipPercentToDisplay = 0;

        if (rounding == ROUND_NONE) {

            tipAmount = billAmount * tipPercent;

            totalAmount = billAmount + tipAmount;

            tipPercentToDisplay = tipPercent;

        }

        else if (rounding == ROUND_TIP) {

            tipAmount = StrictMath.round(billAmount * tipPercent);

            totalAmount = billAmount + tipAmount;

            tipPercentToDisplay = tipAmount / billAmount;

        }

        else if (rounding == ROUND_TOTAL) {

            float tipNotRounded = billAmount * tipPercent;

            totalAmount = StrictMath.round(billAmount + tipNotRounded);

            tipAmount = totalAmount - billAmount;

            tipPercentToDisplay = tipAmount / billAmount;

        }

       

        // display the other results with formatting

        NumberFormat currency = NumberFormat.getCurrencyInstance();

        tipTextView.setText(currency.format(tipAmount));

        totalTextView.setText(currency.format(totalAmount));

       

        NumberFormat percent = NumberFormat.getPercentInstance();

        percentTextView.setText(percent.format(tipPercentToDisplay));

    }

   

    @Override

    public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {

        int keyCode = -1;

        if (event != null) {

           keyCode = event.getKeyCode();

        }

        if (actionId == EditorInfo.IME_ACTION_DONE ||

            actionId == EditorInfo.IME_ACTION_UNSPECIFIED ||

            keyCode == KeyEvent.KEYCODE_DPAD_CENTER ||

            keyCode == KeyEvent.KEYCODE_ENTER) {

            calculateAndDisplay();

        }       

        return false;

    }

   

    @Override

    public void onClick(View v) {

        switch (v.getId()) {

        case R.id.percentDownButton:

            tipPercent = tipPercent - .01f;

            calculateAndDisplay();

            break;

        case R.id.percentUpButton:

            tipPercent = tipPercent + .01f;

            calculateAndDisplay();

            break;

        }

    }

   

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {

            case R.id.menu_settings:

                // Toast.makeText(this, "Settings", Toast.LENGTH_SHORT).show();

                startActivity(new Intent(getApplicationContext(), SettingsActivity.class));

                return true;

            case R.id.menu_about:

                // Toast.makeText(this, "About", Toast.LENGTH_SHORT).show();

                startActivity(new Intent(getApplicationContext(), AboutActivity.class));

                return true;

            

            default:

                return super.onOptionsItemSelected(item);

        }

    }

}

preference.xml

<?xml version="1.0" encoding="utf-8"?>

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <CheckBoxPreference

        android:key="pref_remember_percent"

        android:title="@string/remember_percent_title"

        android:summary="@string/remember_percent_summary"

        android:defaultValue="true" />

    <ListPreference

        android:key="pref_rounding"

        android:title="@string/rounding_title"

        android:summary="@string/rounding_summary"

        android:dialogTitle="@string/rounding_title"

        android:entries="@array/rounding_keys"

        android:entryValues="@array/rounding_values"

        android:defaultValue="@string/rounding_default" />   

</PreferenceScreen>

Activity_Tip_Calculator.xml (xml from Layout)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:padding="10dp" >

    <!-- The bill amount -->

    <TextView

        android:id="@+id/billAmountLabel"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:padding="10dp"

        android:text="@string/bill_amount_label"

        android:textSize="20sp"

        android:textStyle="bold" />

    <EditText

        android:id="@+id/billAmountEditText"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/billAmountLabel"

        android:layout_marginLeft="5dp"

        android:layout_toRightOf="@+id/billAmountLabel"

        android:ems="8"

        android:inputType="numberDecimal"

        android:text="@string/bill_amount"

        android:textSize="20sp" >

        <requestFocus />

    </EditText>

    <!-- The tip percent -->

   

    <TextView

        android:id="@+id/percentLabel"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/billAmountLabel"

        android:layout_below="@+id/billAmountLabel"

        android:padding="10dp"

        android:text="@string/tip_percent_label"

        android:textSize="20sp"

        android:textStyle="bold" />

    <TextView

        android:id="@+id/percentTextView"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/percentLabel"

        android:layout_alignLeft="@+id/billAmountEditText"

        android:padding="5dp"

        android:text="@string/tip_percent"

        android:textSize="20sp" />

    <Button

        android:id="@+id/percentDownButton"

        android:layout_width="45dp"

        android:layout_height="45dp"

        android:layout_alignBaseline="@+id/percentTextView"

        android:layout_marginLeft="25dp"

        android:layout_toRightOf="@+id/percentTextView"

        android:text="@string/decrease"

        android:textSize="20sp" />

    <Button

        android:id="@+id/percentUpButton"

        android:layout_width="45dp"

        android:layout_height="45dp"

        android:layout_alignBaseline="@+id/percentDownButton"

        android:layout_toRightOf="@+id/percentDownButton"

        android:text="@string/increase"

        android:textSize="20sp" />

    <!-- the tip amount -->

   

    <TextView

        android:id="@+id/tipLabel"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/percentLabel"

        android:layout_below="@+id/percentLabel"

        android:padding="10dp"

        android:text="@string/tip_amount_label"

        android:textSize="20sp"

        android:textStyle="bold" />

    <TextView

        android:id="@+id/tipTextView"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/tipLabel"

        android:layout_alignLeft="@id/billAmountEditText"

        android:padding="5dp"

        android:text="@string/tip_amount"

        android:textSize="20sp" />

    <!-- the total -->

   

    <TextView

        android:id="@+id/totalLabel"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/tipLabel"

        android:layout_below="@+id/tipLabel"

        android:padding="10dp"

        android:text="@string/total_amount_label"

        android:textSize="20sp"

        android:textStyle="bold" />

    <TextView

        android:id="@+id/totalTextView"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/totalLabel"

        android:layout_alignLeft="@+id/tipTextView"

        android:padding="5dp"

        android:text="@string/total_amount"

        android:textSize="20sp" />   

</RelativeLayout>

strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">Tip Calculator</string>
    <string name="title_activity_tip_calculator">Tip Calculator</string>
   
    <string name="bill_amount_label">Bill Amount</string>
    <string name="bill_amount"></string>
   
    <string name="tip_percent_label">Percent</string>
    <string name="tip_percent">15%</string>
    <string name="increase">+</string>
    <string name="decrease">-</string>
   
    <string name="tip_amount_label">Tip</string>
    <string name="tip_amount">$0.00</string>
   
    <string name="total_amount_label">Total</string>
    <string name="total_amount">$0.00</string>
   
    <string name="menu_settings">Settings</string>
    <string name="menu_about">About</string>
   
    <string name="title_activity_settings">Settings</string>
   
    <string name="remember_percent_title">Remember Tip Percent</string>
    <string name="remember_percent_summary">Remembers the tip percent for the most recent calculation.</string>
   
    <string name="rounding_title">Rounding?</string>
    <string name="rounding_summary">Sets the rounding option for the calculation.</string>
    <string-array name="rounding_keys">
        <item >None</item>
        <item >Tip</item>
        <item >Total</item>
    </string-array>
    <string-array name="rounding_values">
        <item >0</item>
        <item >1</item>
        <item >2</item>
    </string-array>
    <string name="rounding_default">0</string>
   
    <string name="title_activity_about">About</string>
    <string name="about">This version of the Tip Calculator app calculates all tips on the post-tax total for the bill.</string>

</resources>

This question has been asked twice before but neither answer appears to be correct! Thank you to anyone who can help!

Explanation / Answer

Program create & write:-

<?xml version="1.0" encoding="utf-8"?>

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

<PreferenceCategory>

<EditTextPreference

android:key="Name"

android:title="Full name"

android:summary="Please enter your full name"

android:dialogTitle="Please enter your full name"/>

</PreferenceCategory>

</PreferenceScreen>

2. Enter following code in SettingsFragment

(i) implement OnSharedPreferenceChangeListener and override OnSharedPreferenceChange(SharedPreference s, String key) method

public void OnSharedPreferenceChange(SharedPreference s, String key) {

updatePrefSummary(findPreference(key));

}

(ii) Create methods in SettingsFragment

private void initSummary(Preference p){

if(p instanceof PreferenceGroup){

PreferenceGroup g = (PreferenceGroup) p;

for(int i=0; i<g.getPreferenceCount(); i++){

initSummary(g.getPreference(i));

}else{

updatePrefSummary(p);

}

}

}

private void updatePrefSummary(Preference p){

if(p instanceof EditTextPreference){

EditTextPreference editText = (EditTextPreference)p;

if(p.getSummary().toString().trim().length()!=0){

p.setSummary(editText.getText());

}

}

}

(iii) Append below code in onCreate(Bundle savedInstanceState) {

initSummary(getPreferenceScreen());

}

(iv) Append below code in onResume()

public void onResume(){

super.onResume();

getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(this);

}

(v) Append below code in onStop()

public void onStop(){

super.onStop();

getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(this);

}

4. Override below method

onActivityResult()

{

SharedPreferences s = PreferenceManager.getDefaultSharedPreferences(this);

Strring text = s.getString("Name","Please set full name");

settingEditText.setText(""+text);

}

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.