Task & Document API - Speaker Deck

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Task & Document API Droidcon Paris 2015

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@Mathieu_Calba +MathieuCalba

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@Mathieu_Calba +MathieuCalba

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What is a Task?

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What is a Task? An Activity represents a screen

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What is a Task? An application is often composed of many activities

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What is a Task? An application is often composed of many activities

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What is a Task? An application is often composed of A task is an ordered queue of activities called “back stack”

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What is a Task? Tasks are presented in the overview screen

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What is a Task? • Since 1.0: icon and name • Screenshot added in 4.3 • Icon and name customisation added in 5.0 Overview screen

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What is a Task? Overview screen

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How does it work?

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How does it work? 2 main ways: • Attributes on the tag in the AndroidManifest.xml • Flags on the Intent Task API

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How does it work? android:allowTaskReparenting android:alwaysRetainTaskState android:autoRemoveFromRecents android:clearTaskOnLaunch android:documentLaunchMode android:excludeFromRecents android:finishOnTaskLaunch Task API android:launchMode android:maxRecents android:noHistory android:relinquishTaskIdentity android:stateNotNeeded android:taskAffinity

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How does it work? Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT Intent.FLAG_ACTIVITY_CLEAR_TASK Intent.FLAG_ACTIVITY_CLEAR_TOP Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY Intent.FLAG_ACTIVITY_MULTIPLE_TASK Intent.FLAG_ACTIVITY_NEW_DOCUMENT Intent.FLAG_ACTIVITY_NEW_TASK Task API Intent.FLAG_ACTIVITY_NO_ANIMATION Intent.FLAG_ACTIVITY_NO_HISTORY Intent.FLAG_ACTIVITY_NO_USER_ACTION Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP Intent.FLAG_ACTIVITY_REORDER_TO_FRONT Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED Intent.FLAG_ACTIVITY_RETAIN_IN_RECENTS Intent.FLAG_ACTIVITY_SINGLE_TOP Intent.FLAG_ACTIVITY_TASK_ON_HOME Intent.FLAG_ACTIVITY_HELL

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Have fun with ﬂags!

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Standard behaviour

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Standard behaviour Action: android.intent.action.MAIN Category: android.intent.category.LAUNCHER Flags: • Intent.FLAG_ACTIVITY_NEW_TASK • Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED Start from launcher

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Standard behaviour Start from launcher Action: android.intent.action.MAIN Category: android.intent.category.LAUNCHER Flags: • Intent.FLAG_ACTIVITY_NEW_TASK • Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED

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Action: android.intent.action.MAIN Category: android.intent.category.LAUNCHER Flags: • Intent.FLAG_ACTIVITY_NEW_TASK • Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED Standard behaviour Start from launcher My awesome app

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My awesome app Standard behaviour Start from launcher Action: android.intent.action.MAIN Category: android.intent.category.LAUNCHER Flags: • Intent.FLAG_ACTIVITY_NEW_TASK • Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED

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Intent.FLAG_ACTIVITY_NEW_TASK Start the activity in a new Task depending on the task’s afﬁnity Standard behaviour Start from launcher

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android:taskAffinity Used to determine in which task this activity will be launched when started with Intent.FLAG_ACTIVITY_NEW_TASK Application’s package name by default Standard behaviour Start from launcher

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Action: null Category: null Flags: null My awesome app Standard behaviour Start from within the app My awesome screen

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My awesome app My awesome screen Standard behaviour Start from within the app Action: null Category: null Flags: null

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Standard behaviour Start from overview My awesome app My awesome screen Action: null Category: null Flags: null

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My awesome app My awesome screen Standard behaviour Start from overview Action: null Category: null Flags: null

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Standard behaviour Start from overview My awesome app My awesome screen Action: null Category: null Flags: null

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Standard behaviour Start from overview My awesome app My awesome screen Action: null Category: null Flags: null

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My awesome app Same Intent that launched this activity Action: android.intent.action.MAIN Category: android.intent.category.LAUNCHER Flags: Intent.FLAG_ACTIVITY_NEW_TASK Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED Standard behaviour Restart from back My awesome app My awesome screen

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But there is more to it

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But there is more to it USE ANOTHER APP TO DO A JOB MANY ENTRY POINTS INTO OUR APP MULTITASKING INSIDE AN APP

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But there is more to it USE ANOTHER APP TO DO A JOB MANY ENTRY POINTS INTO OUR APP MULTITASKING INSIDE AN APP

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But there is more to it USE ANOTHER APP TO DO A JOB MANY ENTRY POINTS INTO OUR APP MULTITASKING INSIDE AN APP

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Using other applications startActivity(new Intent().setAction(Intent.ACTION_VIEW) .setData(Uri.parse("http://captaintrain.com"));  What behaviour does occur? New task or not? Opening an Url

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Using other applications Opening an Url It depends on the opened application! startActivity(new Intent().setAction(Intent.ACTION_VIEW) .setData(Uri.parse("http://captaintrain.com"));  What behaviour does occur? New task or not?

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Using other applications • With the old Android browser: new task • With Firefox: new task • With Chrome: same task Opening an Url

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Using other applications Same task Action: android.intent.action.VIEW Category: null Flags: Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP Opening an Url

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Using other applications Opening an Url New task Action: android.intent.action.VIEW Category: null Flags: Intent.FLAG_ACTIVITY_NEW_TASK Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP

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Using other applications In the old Android browser’s manifest: ! Opening an Url

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Using other applications In the old Android browser’s manifest: ! Opening an Url

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android:launchMode Determines how an activity is launched

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android:launchMode • New instance of the activity all the time • Can be anywhere in the stack • Which task is determined by the presence of FLAG_ACTIVITY_NEW_TASK and the android:taskAffinity attribute android:launchMode=“standard”

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android:launchMode • New instance of the activity most of the time • Can be anywhere in the stack • Which task is determined by the presence of FLAG_ACTIVITY_NEW_TASK and the android:taskAffinity attribute • If the targeted task already has this activity at the top of it with this android:launchMode, instead of creating a new instance, it just send a new Intent to this instance, which will receive it in the onNewIntent() method android:launchMode=“singleTop”

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android:launchMode • Only one instance of the activity • Always the root activity of the task • Other activities can be in its task (only standard and singleTop activities) android:launchMode=“singleTask”

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android:launchMode • Only one instance of the activity • Always the root activity of the task • Alone in its task • Every startActivity() behave just like if the Intent has the FLAG_ACTIVITY_NEW_TASK ﬂag android:launchMode=“singleInstance”

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android:launchMode android:launchMode behaviour can be overridden by the FLAG_ACTIVITY_* in the intent

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Using other applications What is the correct behaviour? This way (app -> browser), it’s better to have them in the same task, because the browser is a utility Nothing can be done to prevent a new task to be launched here Opening an Url

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Using other applications Taking a picture final Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);  startActivityForResult(intent, REQUEST_CODE_IMAGE_CAPTURE);

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Using other applications Taking a picture Only works when activity started in the same task Otherwise, an Activity.RESULT_CANCELED is received directly final Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);  startActivityForResult(intent, REQUEST_CODE_IMAGE_CAPTURE);

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Using other applications Sharing via email But it launch in the same task, which is not the expected behaviour on 5.0+ final Intent target = new Intent()  .setAction(Intent.ACTION_SENDTO)  .setData(Uri.fromParts(“mailto", "[email protected]", null))  .putExtra(Intent.EXTRA_TEXT, "Hello Droidcon!");  startActivity(Intent.createChooser(target, "My chooser"));

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Using other applications Sharing via email Action: android.intent.action.SENDTO Category: null Data: mailto:[email protected] Flags: Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP final Intent target = new Intent()  .setAction(Intent.ACTION_SENDTO)  .setData(Uri.fromParts(“mailto", "[email protected]", null))  .putExtra(Intent.EXTRA_TEXT, "Hello Droidcon!");  startActivity(Intent.createChooser(target, "My chooser"));

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Using other applications Intent.FLAG_ACTIVITY_NEW_TASK? No, because we don’t want to be launched in the targeted application’s task Sharing via email

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Using other applications Intent.FLAG_ACTIVITY_NEW_DOCUMENT (5.0+) • Start a new task dedicated to this job • New mail and original application are accessible via the overview screen • Restarting the original task from overview will not bring the mail activity Sharing via email

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Using other applications Compatibility: Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET • Start a the job in the same task • Restarting the original task from overview will not bring the mail activity as it will be ﬁnished Sharing via email

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Using other applications final Intent target = new Intent()  .setAction(Intent.ACTION_SENDTO)  .setData(Uri.fromParts(“mailto", "[email protected]", null))  .putExtra(Intent.EXTRA_TEXT, "Hello Droidcon!");  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {  target.addFlags(Intent.FLAG_ACTIVITY_NEW_DOCUMENT);  } else {  target.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);  }  startActivity(Intent.createChooser(target, "My chooser")); Sharing via email

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Using other applications Sharing via email final Intent target = new Intent()  .setAction(Intent.ACTION_SENDTO)  .setData(Uri.fromParts(“mailto", "[email protected]", null))  .putExtra(Intent.EXTRA_TEXT, "Hello Droidcon!");  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {  target.addFlags(Intent.FLAG_ACTIVITY_NEW_DOCUMENT);  } else {  target.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);  }  startActivity(Intent.createChooser(target, "My chooser"));

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Multiple entry points Internally: • From the notiﬁcation • From a widget • From a wear app Externally: • Multiple icons in the launcher • Responding to a public Intent (URL, sharing, etc)

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Multiple entry points Internally

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Multiple entry points Internally final PendingIntent pendingIntent = TaskStackBuilder.create(this)  .addNextIntentWithParentStack(DetailsActivity. newFocusOnBarcodeIntent(this, id)) .getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT); Action: null Category: null Flags: Intent.FLAG_ACTIVITY_NEW_TASK Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT

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Multiple entry points Allow us to create a stack of activities Internally final PendingIntent pendingIntent = TaskStackBuilder.create(this)  .addNextIntentWithParentStack(DetailsActivity. newFocusOnBarcodeIntent(this, id)) .getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

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Multiple entry points TaskStackBuilder.create(this)  .addParentStack(ParentActivity.class)  .addNextIntent(detailIntent)  .startActivities(); Internally Add the parent’s stack as deﬁned by android:parentActivityName in AndroidManifest.xml

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Multiple entry points Add the targeted activity’s Intent Internally TaskStackBuilder.create(this)  .addParentStack(ParentActivity.class)  .addNextIntent(detailIntent)  .startActivities();

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Multiple entry points Internally Do both at the same time TaskStackBuilder.create(this)  .addNextIntentWithParentTask(detailIntent)  .startActivities();

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Multiple entry points Internally Start the stack TaskStackBuilder.create(this)  .addNextIntentWithParentTask(detailIntent)  .startActivities();

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Multiple entry points Internally Create a pending Intent to be launched TaskStackBuilder.create(this)  .addNextIntentWithParentTask(detailIntent)  .getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

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Multiple entry points Multiple icons in the app drawer Use cases very uncommon: app with multiple speciﬁc jobs Multiple activities declared with intent-ﬁlter: !       Become interesting with non-standard android:launchMode Externally

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Multiple entry points Intercepting Urls: !                         Externally

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Multiple entry points From the old Android browser: Action: android.intent.action.VIEW Category: android.intent.category.BROWSABLE Data: https://www.captaintrain.com/search Flags: Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP Externally S AM E TASK

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Multiple entry points From the email app: Action: android.intent.action.VIEW Category: android.intent.category.BROWSABLE Data: https://www.captaintrain.com/search Flags: Intent.FLAG_ACTIVITY_NEW_TASK Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET Intent.FLAG_ACTIVITY_NEW_DOCUMENT Intent.FLAG_ACTIVITY_NO_ANIMATION Externally N EW TASK

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Multiple entry points From Chrome: Action: android.intent.action.VIEW Category: android.intent.category.BROWSABLE Data: https://www.captaintrain.com/search Flags: Intent.FLAG_ACTIVITY_NEW_TASK Intent.FLAG_ACTIVITY_FORWARD_RESULT Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP Externally N EW TASK

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Multiple entry points What is the good behaviour? Externally

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Multiple entry points What is the good behaviour? Externally ! New task!

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Multiple entry points 2 solutions: • let the current behaviour and let some user have some bad experience • force the creation of a new task for better user experience at the expense of clean code Externally

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Multiple entry points Create a special activity that will catch all Urls you need to catch: !                     And then it will redirect to the correct activity and ﬁnish itself Externally

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Multitasking inside an app Why? • multi-document opened at the same time • writing an email and looking at other emails as references • multi-tasking at the system level is quicker than at the app level

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Introducing Document API (5.0+)

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Introducing Document API (5.0+) Move from app-centric to document-centric system

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Introducing Document API (5.0+) An extension of the Tasks API Move from app-centric to document-centric system

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Multitasking inside an app Only one instance of this document, one task Same as setting FLAG_ACTIVITY_NEW_DOCUMENT alone on the Intent android:launchMode=“standard” mandatory Create new document

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Multitasking inside an app Multiple instance of this document, multiple tasks Same as setting FLAG_ACTIVITY_NEW_DOCUMENT and FLAG_ACTIVITY_MULTIPLE_TASK on the Intent android:launchMode must be standard Create new document

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Multitasking inside an app Create new document Default value of the attribute New task only if FLAG_ACTIVITY_NEW_TASK or speciﬁc android:launchMode

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Multitasking inside an app Create new document Even with FLAG_ACTIVITY_NEW_DOCUMENT, no new document task

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Multitasking inside an app Limiting the history Deﬁne the max number of recent documents for one activity Between 1 and 50, default to 16

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Multitasking inside an app Starting in background

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Multitasking inside an app Starting in background Force the grouping of documents with the original activity Force the behaviour of the android:documentLaunchMode=“always” final ActivityOptions options = ActivityOptions.makeTaskLaunchBehind();  final Intent intent = new Intent(this, NewDocumentActivity.class)  .addFlags(Intent.FLAG_ACTIVITY_NEW_DOCUMENT);  startActivity(intent, options.toBundle());

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Multitasking inside an app In ActivityManager: ! public List getAppTasks() Managing documents

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Multitasking inside an app ActivityManager.AppTask Contains a lot of information on a task, you can: ! public RecentTaskInfo getTaskInfo() ! public void moveToFront() ! public void finishAndRemoveTask() Managing documents

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Multitasking inside an app In a document activity: • finish() will terminate the activity but let the task remain in overview • finishAndRemoveTask() will terminate the activity and remove the task in overview Removing a document

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Multitasking inside an app Use FLAG_ACTIVITY_NEW_DOCUMENT when launching an external activity on 5.0+ On pre-5.0, use FLAG_ACTIVITY_CLEAR_TASK_WHEN_RESET to get roughly the same behaviour Compatibility

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Multitasking inside an app ActivityManager.TaskDescription Customising the overview entry of your activity: ! setTaskDescription(new ActivityManager.TaskDescription( "New label”, bitmap, getColor(R.color.red))); Overview screen customisation (5.0+)

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Multitasking inside an app Overview screen customisation (5.0+)

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Multitasking inside an app Persistance behaviours (5.0+) Default value Persist the activity only if it’s the root of the task

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Multitasking inside an app Persistance behaviours (5.0+) If the activity is the root of the task, the task is not persisted

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Multitasking inside an app Persistance behaviours (5.0+) The activity is persisted across reboot Uses a PersistableBundle in onCreate/onSavedInstanceState to restore/ persist some data across reboot

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Choose the behaviour you want wisely

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Choose the behaviour you want wisely New task only when there is a break in the app ﬂow