Q:

get imageview from row listview (android)

how can I access a single imageview which is located inside a row of a listview?
I have a listview that contains many rows custom xml. each row contains a imageview and a TextView. Once inserted these lines in listview how can I change the bitmap of an imageview to a specific row?

A:

Assuming you know which position you want to update and you're on the UI thread, you can use 
public View getViewForPosition(int position){
    int relativePos = position - listview.getFirstVisiblePosition();
    if( relativePos < 0 || relativePos > listview.getChildCount()){
        return null;
    }
    return listview.getChildAt(relativePos);
}

A return of null from this function means that position is offscreen.  A non null will return the view from getView, and you can then do a findViewById on it to find the child you want.
If calling from a non-UI thread, you can be off by 1 due to calculating as the view mapping is changing.  There is a hack to fix this I came up with once, but I'd suggest just not doing it.
Edit:  here's the thread safe hack.
    public View getViewForPosition(int position){
        int relativePos = position - listview.getFirstVisiblePosition();
        //Hack for allowing us to get a view for a position that is currently being created
        if( (relativePos == listview.getChildCount() || relativePos == -1) && currentProcessingView != null){
            return currentProcessingView;
        }
        if( relativePos < 0 || relativePos >= listview.getChildCount()){
            return null;
        }
        return listview.getChildAt(relativePos);
    }

currentProcessingView should be set in getView to the current position's view at the very beginning, and to null at the end of getView.  If the position is not currently on screen it will return null, you need to be able to handle that.

