Question
Use an EditTextPreference element In this exercise, youll modify the Tip Calculator app presented in this chapter so it uses an EditTextPreference element. Although this
Use an EditTextPreference element
In this exercise, youll modify the Tip Calculator app presented in this chapter so it uses an
EditTextPreference element. Although this type of preference wasnt 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 youre done, a test run should look like this:
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
preferences.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>
SettingsActivity
package com.murach.tipcalculator; import android.app.Activity; import android.os.Bundle; public class SettingsActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Display the fragment as the main content. getFragmentManager().beginTransaction() .replace(android.R.id.content, new SettingsFragment()) .commit(); } }
activity_about.xml
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" tools:context=".AboutActivity" > TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10dp" android:text="@string/about" /> RelativeLayout>
activity_tip_calculator.xml
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" > 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> 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" /> 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" /> 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>
Java TipCalculatorActivity
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); } } }
5:26 3G Tip Calculator Bill Amount 94.60 Percent Tip Total Name 20% $18.92 $113.52 John Smith
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