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TaskStackBuilder

class TaskStackBuilder : MutableIterable<Intent!>
kotlin.Any
   ↳ androidx.core.app.TaskStackBuilder

Utility class for constructing synthetic back stacks for cross-task navigation on Android 3.0 and newer.

In API level 11 (Android 3.0/Honeycomb) the recommended conventions for app navigation using the back key changed. The back key's behavior is local to the current task and does not capture navigation across different tasks. Navigating across tasks and easily reaching the previous task is accomplished through the "recents" UI, accessible through the software-provided Recents key on the navigation or system bar. On devices with the older hardware button configuration the recents UI can be accessed with a long press on the Home key.

When crossing from one task stack to another post-Android 3.0, the application should synthesize a back stack/history for the new task so that the user may navigate out of the new task and back to the Launcher by repeated presses of the back key. Back key presses should not navigate across task stacks.

TaskStackBuilder provides a backward-compatible way to obey the correct conventions around cross-task navigation on the device's version of the platform. On devices running Android 3.0 or newer, calls to the startActivities() method or sending the PendingIntent generated by getPendingIntent(int, int) will construct the synthetic back stack as prescribed. On devices running older versions of the platform, these same calls will invoke the topmost activity in the supplied stack, ignoring the rest of the synthetic stack and allowing the back key to navigate back to the previous task.

Summary

Nested classes

abstract

Public methods

TaskStackBuilder
addNextIntent(@NonNull nextIntent: Intent)

Add a new Intent to the task stack.

TaskStackBuilder
addNextIntentWithParentStack(@NonNull nextIntent: Intent)

Add a new Intent with the resolved chain of parents for the target activity to the task stack.

TaskStackBuilder
addParentStack(@NonNull sourceActivity: Activity)

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

TaskStackBuilder
addParentStack(@NonNull sourceActivityClass: Class<*>)

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

TaskStackBuilder!
addParentStack(sourceActivityName: ComponentName!)

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

static TaskStackBuilder
create(@NonNull context: Context)

Return a new TaskStackBuilder for launching a fresh task stack consisting of a series of activities.

Intent?
editIntentAt(index: Int)

Return the intent at the specified index for modification.

static TaskStackBuilder!
from(context: Context!)

Return a new TaskStackBuilder for launching a fresh task stack consisting of a series of activities.

Intent!
getIntent(index: Int)

Get the intent at the specified index.

Int

Array<Intent!>

Return an array containing the intents added to this builder.

PendingIntent?
getPendingIntent(requestCode: Int, flags: Int)

Obtain a PendingIntent for launching the task constructed by this builder so far.

PendingIntent?
getPendingIntent(requestCode: Int, flags: Int, @Nullable options: Bundle?)

Obtain a PendingIntent for launching the task constructed by this builder so far.

MutableIterator<Intent!>

Unit

Start the task stack constructed by this builder.

Unit
startActivities(@Nullable options: Bundle?)

Start the task stack constructed by this builder.

Public methods

addNextIntent

@NonNull fun addNextIntent(@NonNull nextIntent: Intent): TaskStackBuilder

Add a new Intent to the task stack. The most recently added Intent will invoke the Activity at the top of the final task stack.

Parameters
nextIntent Intent: Intent for the next Activity in the synthesized task stack
Return
TaskStackBuilder: This TaskStackBuilder for method chaining

addNextIntentWithParentStack

@NonNull fun addNextIntentWithParentStack(@NonNull nextIntent: Intent): TaskStackBuilder

Add a new Intent with the resolved chain of parents for the target activity to the task stack.

This is equivalent to calling addParentStack with the resolved ComponentName of nextIntent (if it can be resolved), followed by addNextIntent with nextIntent.

Parameters
nextIntent Intent: Intent for the topmost Activity in the synthesized task stack. Its chain of parents as specified in the manifest will be added.
Return
TaskStackBuilder: This TaskStackBuilder for method chaining.

addParentStack

@NonNull fun addParentStack(@NonNull sourceActivity: Activity): TaskStackBuilder

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

Parameters
sourceActivity Activity: All parents of this activity will be added
Return
TaskStackBuilder: This TaskStackBuilder for method chaining

addParentStack

@NonNull fun addParentStack(@NonNull sourceActivityClass: Class<*>): TaskStackBuilder

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

Parameters
sourceActivityClass Class<*>: All parents of this activity will be added
Return
TaskStackBuilder: This TaskStackBuilder for method chaining

addParentStack

fun addParentStack(sourceActivityName: ComponentName!): TaskStackBuilder!

Add the activity parent chain as specified by manifest <meta-data> elements to the task stack builder.

Parameters
sourceActivityName ComponentName!: Must specify an Activity component. All parents of this activity will be added
Return
TaskStackBuilder!: This TaskStackBuilder for method chaining

create

@NonNull static fun create(@NonNull context: Context): TaskStackBuilder

Return a new TaskStackBuilder for launching a fresh task stack consisting of a series of activities.

Parameters
context Context: The context that will launch the new task stack or generate a PendingIntent
Return
TaskStackBuilder: A new TaskStackBuilder

editIntentAt

@Nullable fun editIntentAt(index: Int): Intent?

Return the intent at the specified index for modification. Useful if you need to modify the flags or extras of an intent that was previously added, for example with addParentStack(Activity).

Parameters
index Int: Index from 0-getIntentCount()
Return
Intent?: the intent at position index

from

static fun from(context: Context!): TaskStackBuilder!

Deprecated: use create(Context) instead

Return a new TaskStackBuilder for launching a fresh task stack consisting of a series of activities.

Parameters
context Context!: The context that will launch the new task stack or generate a PendingIntent
Return
TaskStackBuilder!: A new TaskStackBuilder

getIntent

fun getIntent(index: Int): Intent!

Deprecated: Renamed to editIntentAt to better reflect intended usage

Get the intent at the specified index. Useful if you need to modify the flags or extras of an intent that was previously added, for example with addParentStack(Activity).

Parameters
index Int: Index from 0-getIntentCount()
Return
Intent!: the intent at position index

getIntentCount

fun getIntentCount(): Int
Return
Int: the number of intents added so far.

getIntents

@NonNull fun getIntents(): Array<Intent!>

Return an array containing the intents added to this builder. The intent at the root of the task stack will appear as the first item in the array and the intent at the top of the stack will appear as the last item.

Return
Array<Intent!>: An array containing the intents added to this builder.

getPendingIntent

@Nullable fun getPendingIntent(requestCode: Int, flags: Int): PendingIntent?

Obtain a PendingIntent for launching the task constructed by this builder so far.

Parameters
requestCode Int: Private request code for the sender
flags Int: May be PendingIntent#FLAG_ONE_SHOT, PendingIntent#FLAG_NO_CREATE, PendingIntent#FLAG_CANCEL_CURRENT, PendingIntent#FLAG_UPDATE_CURRENT, or any of the flags supported by Intent#fillIn(Intent, int) to control which unspecified parts of the intent that can be supplied when the actual send happens.
Return
PendingIntent?: The obtained PendingIntent. May return null only if PendingIntent#FLAG_NO_CREATE has been supplied.

getPendingIntent

@Nullable fun getPendingIntent(requestCode: Int, flags: Int, @Nullable options: Bundle?): PendingIntent?

Obtain a PendingIntent for launching the task constructed by this builder so far.

Parameters
requestCode Int: Private request code for the sender
flags Int: May be PendingIntent#FLAG_ONE_SHOT, PendingIntent#FLAG_NO_CREATE, PendingIntent#FLAG_CANCEL_CURRENT, PendingIntent#FLAG_UPDATE_CURRENT, or any of the flags supported by Intent#fillIn(Intent, int) to control which unspecified parts of the intent that can be supplied when the actual send happens.
options Int: Additional options for how the Activity should be started. See android.content.Context#startActivity(Intent, Bundle)
Return
PendingIntent?: The obtained PendingIntent. May return null only if PendingIntent#FLAG_NO_CREATE has been supplied.

iterator

fun iterator(): MutableIterator<Intent!>

Deprecated: Use editIntentAt instead

startActivities

fun startActivities(): Unit

Start the task stack constructed by this builder. The Context used to obtain this builder must be an Activity.

On devices that do not support API level 11 or higher the topmost activity will be started as a new task. On devices that do support API level 11 or higher the new task stack will be created in its entirety.

startActivities

fun startActivities(@Nullable options: Bundle?): Unit

Start the task stack constructed by this builder. The Context used to obtain this builder must be an Activity.

On devices that do not support API level 11 or higher the topmost activity will be started as a new task. On devices that do support API level 11 or higher the new task stack will be created in its entirety.

Parameters
options Bundle?: Additional options for how the Activity should be started. See android.content.Context#startActivity(Intent, Bundle)