Question

I have a general scenario, but couldn’t make out how to handle it.

I have a ListView with each item having different clickable views. Of which 1 is add as friend button beside the user name in the item.

So, in the ListViewAdapter’s getView() i implemented onClick for this button this way.

onClick(){

//make the button invisible, for UX
//change the value of is_friend = 1, in the Adapter ArrayList, which will be helpful when listView is scrolled and getView is called again, to make it visible or invisible.
//Send the info to the server as an AsyncTask
}

This works fine.

Problem:

instead of clicking the add as friend button, I can click the user name go to his profile and click the add as friend button in that Activity.

Now when i comeback to the ListView, the add as friend button is still visible, because the adapter ArrayList has old data taken from server and i am not even changing them.

I thought of StartActivityForResult when user name is clicked. But i might not comeback to the ListView as soon as i click add as friend, there are lot of other actions on a user’s profile.

A familiar case easily handled by many apps. Any idea on how this is done?

Thank You

EDIT:

Though the answers given below work. They are not the best way to do.

So, a better way might be to make a call to a static method of the listViewAdapter to update that value only in its ArrayList??

Answer 1

The comment of gsingh2011 is valid. However, I am guessing that your remark will be something like “I populate the ArrayList by querying the server and I don’t want to do that to often”.

More generally speaking, the comment of gsingh can be translated to this: you should base your adapter and ‘ViewProfileActivity’ on the same data. You can do this by sharing the ArrayList between the two (as a static, or a public member or whatever you want). When you then change something from your ‘ViewProfileActivity’, your ListView will automatically update once you switch back to it (because getView() will be called on its adapter again, which will generate a view based on the new data).

The text above is an answer to your question, but let me just add some other remarks:

• you say you are sending info to a server in an asynctask. You should change this to using an (Intent)Service for that. You don’t have any guarantees that your data will be fully sent when your Activity is put in the background. If you delegate this server synchronization to a Service, it will make sure your process is kept around long enough for your send to finish.
• once you have that service, that would be a nice place to put your “shared data” as discussed above. You could also use a small database for that and let the service only handle the synchronization between your local database and the remote server. Then you have something that is beginning to look like a REST implementation, where your device is caching remote data locally, but in the end is only visualizing the state of the remote server. You can look up an excellent google i/o presentation on dealing with REST servers. This presentation is also nice if you are not interested in the REST part, because (maybe more importantly) it shows you what things you have to take into account when you want to have guarantee of successful persistence of data.