How to manage the stack of activities in Android?

The management of the activity stack in Android can be achieved through the following methods:

1. Using Intent flags: When starting a new Activity, flags can be used to specify the launch mode of the Activity. Common launch modes include:
2. Every time an Activity is started, a new instance is created and placed on top of the stack.
3. SingleTop: If an Activity instance of the same type already exists at the top of the stack, a new instance will not be created. Instead, the existing instance at the top of the stack will be brought to the foreground.
4. SingleTask: If an Activity instance of the same type already exists in the stack, clear all instances above it and bring that Activity instance to the foreground.
5. SingleInstance: The Activity instance occupies its own stack, not shared with any other Activity instance. When starting a SingleInstance type of Activity, the system will create a new stack and place the Activity instance at the top of the stack.
6. By using task stacks, you can specify an activity’s task stack by setting its taskAffinity property. Activities from different task stacks can be switched by calling the startActivity() method. Task stacks can be managed using the following methods:
7. By configuring the launchMode attribute in the AndroidManifest.xml file, one can specify the launch mode of an Activity. Common launch modes include: standard, singleTop, singleTask, and singleInstance.
8. Using the TaskStackBuilder class, you can create a task stack, add multiple activities to the stack, and start the entire task stack using a PendingIntent.
9. By utilizing the Activity lifecycle methods, you can manage the Activity stack. For instance, you can save the current Activity state in the onPause() method and then restore it in the onResume() method.
10. By using ActivityManager, you can utilize the ActivityManager class to access all the running activities of an application and manage them. For instance, you can use the getRunningTasks() method of the ActivityManager class to retrieve a list of currently running activities and manipulate them.

Summary: In Android, activity stack management can be achieved through methods like intent flags, task stacks, activity lifecycle methods, and ActivityManager. Different methods are suitable for different scenarios and requirements.