Question

How can I clear ArrayList and do notifyDataSetChanged() in adapter ListView from fragment?

This is my code in a shortcut:

public class ConnectionsFragment {
    public onClick() {
        // do clear data and notify it (from ListView), how?!
    }

    private class ArrayAdapter extends BaseAdapter {
        ArrayList<ConnectionsModel> data;

        // constructor saves received data to `data`
        // public view `getView()` displays it
    }
}

And I want to do clear data and notify I done it after onClick() in fragment class (or if it is even easier clear ListView until I read new data from API - so I want clear ListView when I do reading from API)...

Answer 1

just create a public method in the adapter and make the variable private to protect it against unwanted edits or clearing:

private ArrayList<ConnectionsModel> mData;

public onClick() { 
    // do clear data and notify it (from ListView), how?! 
    clearData();
} 

public void clearData() {
    mData.clear();
    // do something else here if you want.  Like some kind of visual notification to the user
    notifyDataSetChanged();
}

if your onclick method is in the fragment that's creating the adapter (call it mAdapter in this example), then the onclick would be:

public onClick() { 
    // do clear data and notify it (from ListView), how?! 
    mAdapter.clearData();
}

Answer 2

If your getView() method is pulling from the data ArrayList, you should be able to call data.clear(); and then notifyDataSetChanged(); from within your ArrayAdapter class

Clear ArrayList and do notifyDataSetChanged in adapter ListView from fragment

2 个答案: