Question

I had a fairly simple question regarding activites in an Android application. I’m still a newbie.

In my current android application, I have about 10 activities. If one of the activites is already far back in the activity stack, and I want to reopen it, is it okay to call:

Intent iLogin = new Intent(this, Login.class);

startActivity(iLogin);

If it’s still a little confusing, I’ll give an example. The application launches with activity 1. The user then opens activity 2. Later he opens activity 3 to perform an action. After performing the action, I want the user to go back to activity 1. Is it okay to call the code above? Does it get the activity from th stack, or create a new activity? If no, how can I get the activity from the stack?

UPDATE: I’m interested in recycling activities, rather than creating new ones every time. For instance, not all the activities need to be created new one. Some of them only display data, which can be refreshed upon user request.

Answer 1

Is it okay to call the code above? Does it get the activity from th
stack, or create a new activity? If no, how can I get the activity
from the stack?

Ans. If u use this code, another instance of ur 1st activity is created on the stack , And no it is not OK..

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ok. here is an answer based on ur example above:

I suggest u to use startActivityForResult() to call Activity 2 from Activity 1

here , Activity 2 will behave as sub-Activity…u can setResult and call finish() in 2nd Activity when it succesfully completes its task…

but before finish() put a boolean extra like this:

 i.putExtra("passed2nd", true);

this will indicate that the user has gone through this 2nd activity

Now, u should override, onActivityResult() in your 1st activity,

here u can check the request code and retrieve boolean extra from 2nd activity..

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now, the important part:
depending whether the boolean is true or not, u can decide to call 3rd activity using startActivityForResult() with a different requestcode,

Also, in ur onActivityResult() , u can again check requestcode and do what u wish when activity 3 ends

so now the control will be back to ur 1st activity when 3rd activity ends succesfully

Here is an example to get u started.