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Table of Contents
Chapter 13
Under development.
p. 544
The File > New > Service menu has changed in Android Studio 1.5.1. Now there are explicit entries for the two Intent classes.
p. 547: Code block
- DelayedMessageService.java
package com.hfad.joke; import android.app.IntentService; import android.content.Intent; import android.util.Log; public class DelayedMessageService extends IntentService { public static final String EXTRA_MESSAGE = "message"; public DelayedMessageService() { super("DelayedMessageService"); } @Override protected void onHandleIntent(Intent intent) { synchronized (this) { try { wait(10000); } catch (InterruptedException e) { e.printStackTrace(); } } String text = intent.getStringExtra(EXTRA_MESSAGE); showText(text); } private void showText(final String text) { Log.v("DelayedMessageService", "The message is: " + text); } }
p. 550: Code block
public void onClick(View view) { Intent intent = new Intent(this, DelayedMessageService.class); intent.putExtra(DelayedMessageService.EXTRA_MESSAGE, getResources().getString(R.string.button_response)); startService(intent); }
p. 553
In other words, while most Intent methods run off the main thread, but onStartCommand() runs on the main thread.
p. 554
- DelayedMessageService.java
package com.hfad.joke; import android.app.IntentService; import android.content.Intent; import android.os.Handler; import android.widget.Toast; public class DelayedMessageService extends IntentService { public static final String EXTRA_MESSAGE = "message"; private Handler handler; public DelayedMessageService() { super("DelayedMessageService"); } @Override public int onStartCommand(Intent intent, int flags, int startId) { // This method runs on the main thread, so the Handler that's // instantiated here will also be running on the main thread. handler = new Handler(); return super.onStartCommand(intent, flags, startId); } @Override protected void onHandleIntent(Intent intent) { synchronized (this) { try { wait(10000); } catch (InterruptedException e) { e.printStackTrace(); } } String text = intent.getStringExtra(EXTRA_MESSAGE); showText(text); } private void showText(final String text) { handler.post(new Runnable() { @Override public void run() { Toast.makeText(getApplicationContext(), text, Toast.LENGTH_LONG).show(); } }); } }
pp. 562-563: Code block
- DelayedMessageService.java
package com.hfad.joke; import android.app.IntentService; import android.content.Intent; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.app.TaskStackBuilder; import android.content.Context; public class DelayedMessageService extends IntentService { public static final String EXTRA_MESSAGE = "message"; public static final int NOTIFICATION_ID = 5453; public DelayedMessageService() { super("DelayedMessageService"); } @Override protected void onHandleIntent(Intent intent) { synchronized (this) { try { wait(10000); } catch (InterruptedException e) { e.printStackTrace(); } } String text = intent.getStringExtra(EXTRA_MESSAGE); showText(text); } private void showText(final String text) { Intent intent = new Intent(this, MainActivity.class); // No, really ... this is a common enough pattern, why doesn't // Android do the backstack/pendingIntent construction at a // higher level? TaskStackBuilder stackBuilder = TaskStackBuilder.create(this); stackBuilder.addParentStack(MainActivity.class); stackBuilder.addNextIntent(intent); PendingIntent pendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT); Notification notification = new Notification.Builder(this) .setSmallIcon(R.mipmap.ic_launcher) .setContentTitle(getString(R.string.app_name)) .setAutoCancel(true) .setPriority(Notification.PRIORITY_MAX) .setDefaults(Notification.DEFAULT_VIBRATE) .setContentIntent(pendingIntent) .setContentText(text) .build(); NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); notificationManager.notify(NOTIFICATION_ID, notification); } }
pp. 580-581: Code block
- OdometerService.java
package com.hfad.odometer; import android.app.Service; import android.content.Context; import android.content.Intent; import android.location.Location; import android.location.LocationListener; import android.location.LocationManager; import android.os.Binder; import android.os.Bundle; import android.os.IBinder; public class OdometerService extends Service { private final IBinder binder = new OdometerBinder(); private static double distanceInMeters; private static Location lastLocation = null; private LocationListener listener; private LocationManager locManager; public class OdometerBinder extends Binder { OdometerService getOdometer() { return OdometerService.this; } } @Override public IBinder onBind(Intent intent) { return binder; } @Override public void onCreate() { listener = new LocationListener() { @Override public void onLocationChanged(Location location) { if (lastLocation == null) { lastLocation = location; } distanceInMeters += location.distanceTo(lastLocation); lastLocation = location; } @Override public void onProviderDisabled(String arg0) {} @Override public void onProviderEnabled(String arg0) {} @Override public void onStatusChanged(String arg0, int arg1, Bundle bundle) {} }; locManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE); locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, listener); } @Override public void onDestroy() { if (locManager != null && listener != null) { locManager.removeUpdates(listener); locManager = null; listener = null; } } public double getMiles() { return this.distanceInMeters / 1609.344; } }
Permissions?
You will probably see some editor rage even after you add the needed permissions to AndroidManifest.xml. The autofix will suggest “Add Permission Check.” This is because the way Android handles permissions has changed in Android 6.0 (API level 23). Instead of the permissions being asked to be granted at install time, they are asked at run time.
If the device is running Android 5.1 or lower, or your app's target SDK is 22 or lower: If you list a dangerous permission in your manifest, the user has to grant the permission when they install the app; if they do not grant the permission, the system does not install the app at all.
If the device is running Android 6.0 or higher, and your app's target SDK is 23 or higher: The app has to list the permissions in the manifest, and it must request each dangerous permission it needs while the app is running. The user can grant or deny each permission, and the app can continue to run with limited capabilities even if the user denies a permission request.
For the purposes of this app, we can work around this change by targeting SDK 22 instead of SDK 23. But if you plan on going further with Android development, you should carefully read the developer documentation regarding requesting permissions.
To downgrade the target SDK to 22, with the left panel set to “Android” mode, open Grade Scripts > Build.grade () and change
defaultConfig { applicationId "com.hfad.odometer" minSdkVersion 16 targetSdkVersion 23 versionCode 1 versionName "1.0" }
to
defaultConfig { applicationId "com.hfad.odometer" minSdkVersion 16 targetSdkVersion 22 versionCode 1 versionName "1.0" }
The IDE will tell you that the project needs to be synced, which you should do. And for good measure, from the menu bar, do a Build > Clean Project.