How to jump to main activity from subchild activity without using Intent?

Question

I have following activities. 1) Main activity 2) Activity 1 3) Activity 2

This is the way Activities is connected together

Main Activity -> Activity 1 -> Activity 2(Create Background Async Task) So "Activity 1" is child activity and "Activity 2" is a subchild activity. And creating Background Async task from "Activity 2"

So Let's say I am currently on "Activity 2" screen and Backround Async task is running. Now after some failure event on "Background Async task", I want go back to "Main activity". What can be good way to do this?

Few way I am thinking is, 1) To restart the app completely 2) To create new Intent of Main activity from Background Async task just like we created "Activity 1 & 2".

I am not sure which one from this is good to use. Is there any other way to do it?

I am kind of newbie to android. I am currently using BroadcastReceiver(on Activity 1 & 2)to finish current activity when Background Async task broadcast failure event but sometimes it jump to "Main activity" and sometimes jump to "Activity 1". So not working as I am looking for.

Will you please suggest a good way to do this? [Sorry, I had to ask this question once again. Because old question was deleted]

@Rohit, I tried way you suggested to finish Activity 1 before going to Activity2. That also works but It create one another problem.

After doing this, when I press back button it directly go to Main activity rather than Activity 1 since it no longer exist.

Is there any solution which can get this both thing working? I want to jump to Activity 1 when back button is pressed. And I want to jump to Main activity when Background Async task created from Activity 2 find problem.

[Edit] Let me describe more specific case.

Main Activity list open Wifi access point based hardware.

When clicked on particular listed access point, It opens Login activity and ask for user id & password for hardware access. Login activity onCreate function also create TcpAsyncTask background task which will communicate with hardware(which has WiFi accesspoint feature) for authentication and data passing.

When user enter login detail and click on login button, It will create momentary background task LoginDeviceAsyncTask . This task will communicate to hardware via TcpAsyncTask created earlier to verify authentication. If authentication is successful, it will create Navigation activity using startActivityForResult.

In the Navigation activity, It list options for opening specific window eg Dashboard. History. When user select Dashboard from options, it creates Dashboard activity using startActivity. When user select History from options, it creates History activity using startActivity.

So if Dashboard activity is opened, it display some data periodically received from hardware using TcpAsyncTask(created earlier in Login activity)

Similarly if History activity is opened, it display some data periodically received from hardware using TcpAsyncTask(created earlier in Login activity)

Dashboard/History activity has options to move to History/Dashboard activity directly. For this it creates selected activity using startActivity and finish current activity.

Now my problem is, Let's say I am in Dashboard activity and it is displaying data received from hardware using TcpAsyncTask. Now somehow TcpAsyncTask fails to communicate with hardware and at this point I want to move to Main activity directly.

In TcpAsyncTask, I don't have context of activity like Navigation/Dashboard/History which was created after TcpAsyncTask. May be I can get this context in TcpAsyncTask using some MainActivity variables which is updated as per create/finish. Am I correct?

I am current broadcasting to close from TcpAsyncTask and receiving broadcast message in Navigation/Dashboard/History activity using BroadcastReceiver and finish particular activity which received broadcast close message. But sometimes it jump to Main activity and sometimes it jump to Navigation activity when sendBroadcast from TcpAsyncTask to close.

Answer 1

Pass Context in your AsyncTask and through that you can kill your Activity 1 as well as Activity 2

((Activity)context).finish();

You can do this for both activities by passing context of both.

Answer 2

Firstly, remember that code being run in an inactive activity when it is not in the foreground cannot be relied upon. So you should not rely on background async task. Instead, use a Service which does the background processing; this is precisely what Services are meant to encompass (among other persistent processing). While it is quite a lot for a beginner to learn, it will save you a LOT of trouble long term, as its lifecycle is far easier to manage than complex webs of activities and their relationships and lifecycles.

You should read up on android "Back Stacks". If you finish an activity, the previous activity on the back stack will be displayed. These are like the history browsers maintain that determine how browser back-buttons to operate.

So what you need is the main activity spawning a new instance of the sub-activity. Then when the user navigates the back button, the previous activity in the back stack (your main activity) will be resumed. This will not need intents.

However, for an activity to be triggered by a background processing task, I strongly recommend using a Service and intents to co-ordinate it all.

Answer 3

One possible solution is to start Activity 2 with startActivityForResult() then during its processing, you can call setResult() to indicate success or failure. In Activity 1, override onActivityResult() and detect the result of Activity 2. If Activity 2 indicates a failure, simply call finish() on Activity 1 to return to the main activity.