activity startup mode
. Concept
Activity startup mode defines the rules for activity initiation, which determines whether an activity's instance is created or reused
. Properties
The Activity's startup mode is set in the <activity> tab in Menifest.xml, and the property is Launchmode
. Classification
the activation mode of activity is divided into four categories: standard, Singletop, Singletask, singleinstance
. Remarks
Android uses task to manage different activity. When an activity is started, the system creates a task before starting the activity the entrance. We can understand the task as a stack.
. Standard (normal mode)
settings: System default mode, not set
feature: Each time you create an activity, a new activity object will be created and pinned
Example: Jump from activity A to activity B, then jump to Acticitya, the stack is: A, B , a
. Singletop (stack top singleton mode)
setting: Launchmode = "Singletop"
Features: Check whether the top element of the stack is the current activity, if it is, reuse it, or, if not, create a new activity, pinned
Example: The current stack is: A, B, C, the current stack top is C, if jump to C, then the C, the stack is: A, B, C
. Singletask (full stack singleton mode)
setting: Launchmode = "Singletask"
Features: Check whether the full stack element has the current activity, if any, so that the activity above the activity out of the stack, so that it is pinned
Example: The current stack is: A, B, C, D, if jump to B, then C, d out of the stack, the stack is: a-b
. SingleInstance (System singleton mode)
setting: Launchmode = "SingleInstance"
Features: System-wide checks for the presence of the activity and, if present, multiplexing
from the above summary
same point: target activity must be pinned
different points: standard creates a new activity instance each time
Singletop/singletask first checks for the presence of the activity, and the presence is reused.
Singletop due to the top operation of the stack, do not need to be pinned; Singletask must be pinned
Singletop/singletask are implemented in-stack singleton
SingleInstance is the implementation of the system single case
singletask/singletop mode, all calls to Onnewintent ()
Androidのactivity startup mode
