Question

I can I retain ArrayList<HashMap<String, String>> in bundle?

I want to display ListView immediately after rotating the screen.

Answer 1

You dont have to save it in the Bundle. In fact, that seems like a lot of info to store in a Bundle.

Since you are just saving a HashMap of String objects, you could make a class to cache it for you or make it a static field in the class.

Static fields are fine to use as long as they dont contain a reference to the Activity or a View or Drawable. (That can cause memory leaks)

The simplest way you could do this might just be:

private static HashMap<String,String> myMap = new HashMap<String,String>();

Because this field is static, it will not be recreated when your activity is recreated. Rather, it will still be there for you to use with the same values.

More ways to store data:

(These techniques apply to sharing data over a configuration change also).

http://developer.android.com/guide/faq/framework.html#3

How do I pass data between Activities/Services within a single application?

It depends on the type of data that you want to share:

Primitive Data Types

To share primitive data between Activities/Services in an application,
use Intent.putExtras(). For passing primitive data that needs to
persist use the Preferences storage mechanism.

Non-Persistent Objects

For sharing complex non-persistent user-defined objects for short
duration, the following approaches are recommended:

Singleton class

You can take advantage of the fact that your application components
run in the same process through the use of a singleton. This is a
class that is designed to have only one instance. It has a static
method with a name such as getInstance() that returns the instance;
the first time this method is called, it creates the global instance.
Because all callers get the same instance, they can use this as a
point of interaction. For example activity A may retrieve the instance
and call setValue(3); later activity B may retrieve the instance and
call getValue() to retrieve the last set value. A public static
field/method

An alternate way to make data accessible across Activities/Services is
to use public static fields and/or methods. You can access these
static fields from any other class in your application. To share an
object, the activity which creates your object sets a static field to
point to this object and any other activity that wants to use this
object just accesses this static field.

A HashMap of WeakReferences to Objects

You can also use a HashMap of WeakReferences to Objects with Long
keys. When an activity wants to pass an object to another activity, it
simply puts the object in the map and sends the key (which is a unique
Long based on a counter or time stamp) to the recipient activity via
intent extras. The recipient activity retrieves the object using this
key.

Persistent Objects

Even while an application appears to continue running, the system may
choose to kill its process and restart it later. If you have data that
you need to persist from one activity invocation to the next, you need
to represent that data as state that gets saved by an activity when it
is informed that it might go away.

For sharing complex persistent user-defined objects, the following
approaches are recommended:

• Application Preferences
• Files
• contentProviders
• SQLite DB

If the shared data needs to be retained across points where the
application process can be killed, then place that data in persistent
storage like Application Preferences, SQLite DB, Files or
ContentProviders. Please refer to the Data Storage for further details
on how to use these components.