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Pass reference to another activity - Android

Answer 1

+3 A:

Put/Get extras are not passed via constructors, you have to explicitly read from the intent, probably in the onCreate method

First Activity

Intent myIntent = new Intent();
myIntent.putExtra("key", "value");
startActivity(myIntent);

New Activity

code in onCreate

Intent myIntent = getIntent(); 
myIntent.getExtra("key");

If you want to pass custom classes, your class must implement serializable and you then read by:

Bundle e = getIntent().getExtras();
Object obj=(Object) e.getSerializable("key");

Pentium10 2010-06-20 13:03:01

My "custom" class should implement serializable?

Gibbon 2010-06-20 13:06:41

Would it be better to to the database work in First Activity and pass that in with the intent.It would need to have two details. My values from database is like this:"animal","cat""animal","dog""food","potato"

Gibbon 2010-06-20 13:09:47

Create a reduced class that stores fields you want to pass, kinda enum type class. This class will implement serializable. Then you put the data into that class on whatever activity or model level you want. You can that pass it to another activity with the intent, and you will read the data as you want. Keep it simple if you need to pass 5 fields, you create a class having 5 members to store the data. Or even simpler you can use the Extras to avoid this step. I don't know how complicate is your result.

Pentium10 2010-06-20 13:17:28

they values are in pairs:Kind (i.e. Animal or food)Instance (Cat, potato)But, cats are never food ;-) lol

Gibbon 2010-06-20 13:21:15

Answer 2

A:

I agree with Mr. Castiblanco. Do not try to do this.

Your Adapter holds a reference to the main Activity, the one with the ListView that the Adapter is attached to. If you were to get your Adapter over to the new Activity, then your new Activity will hold a reference to your old Activity. This will prevent Android from being able to destroy your old Activity to free up memory for other applications, since your new Activity will hold a reference to it, preventing garbage collection.

If you need to share a data model between activities, hold that data model outside of those activities (e.g., database, Service, Application). Your Adapter is not your data model.

CommonsWare 2010-06-20 13:26:15

So, I should redeclare the database class and connection in my Edit class?

Gibbon 2010-06-20 13:34:45

OR, as I said in another comment.Some kind of array map that is passed in the extras?

Gibbon 2010-06-20 13:36:30

"I should redeclare the database class and connection in my Edit class?" That is one approach. "Some kind of array map that is passed in the extras?" As I wrote, if you need to share a data model between activities, hold that data model outside of those activities (e.g., database, Service, Application). Passing your entire data model between activities via extras is not an approach I would recommend.

CommonsWare 2010-06-20 14:12:16

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Pass reference to another activity - Android

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