Best Way To Pass Objects From One Activity To Another

I have read about global static technique in which we create a class with static fields which can be accessed in any activity. Is there any other way to pass large data sets like A

Solution 1:

Intent intent = new Intent(getBaseContext(), NextActivity.class);
intent.putExtra("arraylist", new ArrayList<String>());

If your ArrayList contains another Object that you have created yourself, for instance Friend.class, you can implement the Friend.class with Serializable and then:

Intent intent = new Intent(getBaseContext(), NextActivity.class);
intent.putExtra("friendlist", new ArrayList<Friend>());

And for receiving it on NextActivity.class:

Bundleextras= getIntent().getExtras();
    if(extras != null){
        ArrayList<Friend> friends = extras.getSerializable("friendlist");
    }

Well, instead of passing an empty ArrayList, you'll have to put values into the ArrayList and then pass it, but you get the idea.

Solution 2:

You should pack your information into the Intent object you create to call your next Activity. There is a extras Bundle object.

You can use either the Serializable interface or the Android-specific Parcelable interface to pass non-primitive objects.

The Android Developer site has a handy Notepad Tutorial with an example of putting information into the intent.

From their tutorial:

super.onListItemClick(l, v, position, id);
Cursorc= mNotesCursor;
c.moveToPosition(position);
Intenti=newIntent(this, NoteEdit.class);
i.putExtra(NotesDbAdapter.KEY_ROWID, id);
i.putExtra(NotesDbAdapter.KEY_TITLE, c.getString(
        c.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE)));
i.putExtra(NotesDbAdapter.KEY_BODY, c.getString(
        c.getColumnIndexOrThrow(NotesDbAdapter.KEY_BODY)));
startActivityForResult(i, ACTIVITY_EDIT);

Solution 3:

As long as you stay in the same application( speak: same JVM ) you do not need to bother with intents, parcelables, serialisation etc - all objects are on same heap and can be passed via singletons, DI containers like roboguice or whatever you see fit.

If you like to push data to an other application, best technique would be to pass it as JSON/XML serialized stuff.

Solution 4:

Passing Hashmap is pretty simple, All Collections objects implement Serializable (sp?) interface which means they can be passed as Extras inside Intent

Use putExtra(String key, Serializable obj) to insert the HashMap and on the other acitivity use getIntent().getSerializableExtra(String key), You will need to Cast the return value as a HashMap though.