Tuesday

How to update listview in android

First you have to remember Don't at any circumstances create a new adapter (or a new data source that holds the Adapter's data).
There's an exception of course, you obviously have to create a new Adapter in OnCreate() { }.
Create a new ArrayList of HashMaps that holds the data

hashMapListForListView = new ArrayList<HashMap<String,String>>();

we can fill it up by calling:

entitiesHashMap.put("name", "Ball");

entitiesHashMap.put("category", "Sport");

entitiesHashMap.put("price", "2.99");

entitiesHashMap.put("imageUri", ball.Uri);

and then, we add it to the List:

hashMapListForListView.add(entitiesHashMap);

We can do this over n over, as many times as we want.
Create a new Adapter in your OnCreate() {}

adapterForList = new SimpleAdapter(Main.this,

hashMapListForListView, R.layout.detailedview,

new String[] {"name", "category", "price", "imageUri"},

new int[] { R.id.EntityName, R.id.Category, R.id.Price, R.id.ThumbImage });

listView.setAdapter(adapterForList);

What we're doing here is that we create a new SimpleAdapter, and tell it to use hashMapForListView as data source, and also tell the listView to use adapterForList as Adapter.
R.layout.detailedview is my own Layout file, that includes 3 textviews called "R.id.EntityName, R.id.Category, R.id.Price, " and an ImageView called "R.id.ThumbImage".
As you can see, we tell the Adapter to use these UI elements.
The refreshing
Since we have data in the List of HashMaps, we can overwrite the values, simply by calling