Activity Launch Modes

Activity Launch Modes

"standard" (the default mode)
 Default. The system creates a new instance of the activity in the task from which it was started and routes the intent to it. 
    The activity can be instantiated multiple times, each instance can belong to different tasks, and one task can have multiple 
    instances.
  
  "singleTop"
    If an instance of the activity already exists at the top of the current task, the system routes the intent to that instance
    through a call to its onNewIntent() method, rather than creating a new instance of the activity. The activity can be 
    instantiated multiple times, each instance can belong to different tasks, and one task can have multiple instances 
    (but only if the activity at the top of the back stack is not an existing instance of the activity).  
    
  Note: When a new instance of an activity is created, the user can press the Back button to return to the previous activity. 
  But when an existing instance of an activity handles a new intent, the user cannot press the Back button to return to the 
  state of the activity before the new intent arrived in onNewIntent().
  
  "singleTask"
    The system creates a new task and instantiates the activity at the root of the new task. However, if an instance of 
    the activity already exists in a separate task, the system routes the intent to the existing instance through a call 
    to its onNewIntent() method, rather than creating a new instance. Only one instance of the activity can exist at a time.

    Note: Although the activity starts in a new task, the Back button still returns the user to the previous activity.
    
  "singleInstance".
    Same as "singleTask", except that the system doesn't launch any other activities into the task holding the instance. 
    The activity is always the single and only member of its task; any activities started by this one open in a separate task.