Listview shows wrong images

Question

I have a ListView with an ArrayAdapter holding rows with a Image and a String. This worked fine until I decided that the loading of the images was to slow so I could not loa

Answer 1

The problem comes from your convertView: it's the same single instance that is used throughout the list, so when your asynchronous loading is complete, the image is changed when the listview is trying to paint a different item using the same convertView (or in that case, its child imageView).

painting position 1, uses placeholder, starts loading image 1 asynchronously
painting position 2, uses placeholder, starts loading image 2 asynchronously
image 1 loading is complete, calling setImageBitmap on imageView
painting position 3, uses image 1, starts loading image 3 asynchronously
etc.

What you can do though is keep a cache of Bitmaps in the listadapter. Something like this:

private Bitmap[] bitmapList;
private Bitmap bitmapPlaceholder;  

private void initBitmapListWithPlaceholders(){ 
// call this whenever the list size changes
// you can also use a list or a map or whatever so you 
// don't need to drop all the previously loaded bitmap whenever 
// the list contents are modified
    int count = getListCount();
    bitmapList = new Bitmap[count];
    for(int i=0;i