Refresh Listview When Using Hashmap

I have a multiline listview , implemented using hashmaps . I get my data from a database . I have another activity in which i am adding my items , which is being added to the data

Solution 1:

This is probably because findFragmentByTag() is not able to find the required fragment and so is returning null, resulting in NullPointerException when you try to access it. You can try a workaround by retrieving the tag for fragment and storing it in activity class variable for further access as follows:

In your activity class, declare a private String variable and getter/setter methods for it:

publicString fragmentView1Tag;

publicStringgetfragmentView1Tag() {
    return fragmentView1Tag;
}

publicvoidsetfragmentView1Tag(String fragmentView1Tag) {
    this.fragmentView1Tag = fragmentView1Tag;
}

In FragmentView1 class, retrieve the tag of the fragment and set fragmentView1Tag variable:

Stringtag= getTag();
    ((YourActivityName) getActivity()).setfragmentView1Tag(tag);

And now while retrieving the fragment in activity class, use the above getter method:

FragmentView1f= (FragmentView1) this.getSupportFragmentManager().findFragmentByTag(getfragmentView1Tag);

Solution 2:

Use a cursor to get all the rows from the database. Then use a cursor adapter to populate the list. After you add a new row to the database, just call notifyDataSetChanged(); on the cursor adapter.