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listview – Android, using SimpleCursorAdapter to set colour not just strings

Posted by: admin June 15, 2020 Leave a comment

Questions:

I have a simple cursor adapter set on a list in my application as follows:

private static final String fields[] = {"GenreLabel", "Colour", BaseColumns._ID};


datasource = new SimpleCursorAdapter(this, R.layout.row, data, fields, new int[]{R.id.genreBox, R.id.colourBox});

R.layout.row consists of two TextViews (genreBox and colourBox). Rather than setting the content of the TextView to the value of “Colour” , I would like to set its background colour to that value.

What would I need to do to achieve this?

How to&Answers:

Check out SimpleCursorAdapter.ViewBinder.

setViewValue is basically your chance to do whatever you wish with the data in your Cursor, including setting the background color of your views.

For example, something like:

SimpleCursorAdapter.ViewBinder binder = new SimpleCursorAdapter.ViewBinder() {
    @Override
    public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
        String name = cursor.getColumnName(columnIndex);
        if ("Colour".equals(name)) {
            int color = cursor.getInt(columnIndex);
            view.setBackgroundColor(color);
            return true;
        }
        return false;
    }
}
datasource.setViewBinder(binder);

Update – if you’re using a custom adapter (extending CursorAdaptor) then the code doesn’t change a whole lot. You’d be overriding getView and bindView:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if (convertView != null) {
        return convertView;
    }
    /* context is the outer activity or a context saved in the constructor */
    return LayoutInflater.from(context).inflate(R.id.my_row);
}

@Override
public void bindView(View view, Context context, Cursor cursor) {
    int color = cursor.getInt(cursor.getColumnIndex("Colour"));
    view.setBackgroundColor(color);
    String label = cursor.getString(cursor.getColumnIndex("GenreLabel"));
    TextView text = (TextView) findViewById(R.id.genre_label);
    text.setText(label);
}

You’re doing a bit more manually, but it’s more or less the same idea. Note that in all of these examples you might save on performance by caching the column indices instead of looking them up via strings.

Answer:

What you’re looking for requires a custom cursor adapter. You can subclass SimpleCursorAdapter. This basically give access to the view as its created (although you’ll be creating it yourself).

See this blog post on custom CursorAdapters for a complete example. Particularly, I think you’ll need to override bindView.