Question

Exercise 11-4 Create a Reminder app

In this exercise, you’ll add a service to a Reminder app that displays a notification every hour that says, “Look into the distance. It’s good for your eyes.”

Test the app

1. Start Android Studio and open the project named ch11_ex4_Reminder.

2. Review the code. Note that it contains a layout and a class for an activity, but no class for a service.

1. Run the app. Note that it displays a message that describes the app as well as a Start Service button and a Stop Service button. Note also that clicking on these buttons doesn’t do anything.

Add a service

2. Add a class for a service. If this service is started or stopped, it should display an appropriate message in the LogCat view.

3. Open the Android manifest file and register the service.

4. Open the class for the activity. Then, add code that’s executed when the user clicks the Start Service button. This code should start the service and display a toast that says “Service started”.

5. Add code that’s executed when the user clicks the Stop Service button. This code should stop the service and display a toast that says “Service stopped”.

6. Run the app and test the buttons. They should display an appropriate toast on the user interface and an appropriate message in the LogCat view.

Add a timer

7. Open the service class and add code that uses a timer to print a message to the LogCat view. This message should say, “Look into the distance. It’s good for your eyes!” To make this timer easy to test, you can have it execute every 10 seconds or so.

8. Run the app and check the LogCat view to make sure the timer is working correctly.

Add a notification

9. Open the service class and add code to the timer task that displays a notification that says, “Look into the distance. It’s good for your eyes.”

10. Run the app and make sure the notification is working correctly.

11. If necessary, modify the code for the timer so it only displays the notification every hour.

activity_reminder.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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".ReminderActivity" >

    <TextView
        android:id="@+id/messageTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        android:textSize="18sp" />

    <Button
        android:id="@+id/startServiceButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/messageTextView"
        android:layout_below="@+id/messageTextView"
        android:layout_marginTop="15dp"
        android:text="@string/start_service" />

    <Button
        android:id="@+id/stopServiceButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/startServiceButton"
        android:layout_marginLeft="14dp"
        android:layout_toRightOf="@+id/startServiceButton"
        android:text="@string/stop_service" />

</RelativeLayout>

ReminderActivity.java

package com.murach.reminder;

import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class ReminderActivity extends Activity implements OnClickListener {

    private Button startServiceButton;
    private Button stopServiceButton;
    
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_reminder);
      
        startServiceButton = (Button) findViewById(R.id.startServiceButton);
        stopServiceButton = (Button) findViewById(R.id.stopServiceButton);
        
        startServiceButton.setOnClickListener(this);
        stopServiceButton.setOnClickListener(this);       
   }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
           case R.id.startServiceButton:
              // put code to start service and display toast here
              break;
           case R.id.stopServiceButton:
              // put code to stop service and display toast here
              break;
        }
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.murach.reminder"
    android:versionCode="1"
    android:versionName="1.0" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.murach.reminder.ReminderActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>