CODEWITHSUNDEEP
androidlistview
chathura
chathura

Reputation: 3452

Saving the ListView state in android

I have a ListView in my main page(MainActivity.java) and I want to keep the ListView's position(if it was scrolled up I want to show the exact ListView position) when user comes back to main page.

Since the MainActivity goes to onPause() -> onStop() method when the user clicked a list item, I am saving the state of ListView inside onPause(). For get the return Parcelable value I use a global variable called state.

state = list.onSaveInstanceState(); //line 1

When the user comes back to the MainActivity() it goes through the onStart(), so I get the saved states inside onStart().

if (state != null) {
        //set adapter to listview
        list.setAdapter(myAdapter);
        //Restore previous state
        list.onRestoreInstanceState(state);
}

The problem is line 1 doesn't return any state.(It gives a null value). How to fix this?

Thanks.

Upvotes: 0

Views: 7169

Answers (2)

Alpesh Gujarati
Alpesh Gujarati

Reputation: 78

To get current position of listview you have to implement OnScrollListener and set listener with your listview like,

listView.setOnScrollListener(this);

then, in onScroll method you can do your stuff

@Override
public void onScroll(AbsListView absListView, int firstVisibleItem, int totalVisibleItem, int totalItemInList) {
    // TODO Auto-generated method stub
            // here you can save listview's scroll state
            // you can see methods parameters
}

and when you get back to your main activity you can use setSelection method of listview like, 

listView.setSelection(firstVisibleItem);

i hope this is all you want.

Upvotes: 0

alecnash
alecnash

Reputation: 1768

I use this:

Parcelable state = listView.onSaveInstanceState();

before adding the adapter and this:

listView.onRestoreInstanceState(state);

exactly after setting the adapter and I have the result you are looking for. Just try it out

Upvotes: 1

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