Android provides a widget gallery by default. Widget gallery is the basic widget inside android. I also provide a more complicated gallery in my previous post: Android Infinite Loop Gallery. Using this gallery, an android programmer can create a picture gallery, or a album in a 5 minutes. Here, I will give you an example to show how easily to create a gallery in android. And You can also download the example, and source code to try.

The class of the basic gallery is android.widget.Gallery; In this example, I will show 8 pictures in the android gallery. So let’s see the layout file main.xml first.

<?xml version="1.0" encoding="utf-8"?>
<gallery xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/gallery"
	android:layout_width="fill_parent"
	android:layout_height="fill_parent"
/>

As we show in the above example, we just simply put a widget gallery inside layout, and assign the id as “gallery”, which we will use in Activity class. Next code snap is the Activity class:

public class GalleryLoop extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Reference the Gallery view
        Gallery g = (Gallery) findViewById(R.id.gallery);
        g.setSpacing(2);

        // Set the adapter to our custom adapter (below)
        g.setAdapter(new ImageAdapter(this));
    }


    public class ImageAdapter extends BaseAdapter {

        public ImageAdapter(Context c) {
            mContext = c;
        }

        public int getCount() {
            return mImageIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {

        	ImageView i = new ImageView(mContext);

            i.setImageResource(mImageIds[position]);
            i.setScaleType(ImageView.ScaleType.FIT_XY);
            i.setLayoutParams(new Gallery.LayoutParams(136, 88));
            return i;
        }

        private Context mContext;

        private Integer[] mImageIds = {
                R.drawable.gallery_photo_1,
                R.drawable.gallery_photo_2,
                R.drawable.gallery_photo_3,
                R.drawable.gallery_photo_4,
                R.drawable.gallery_photo_5,
                R.drawable.gallery_photo_6,
                R.drawable.gallery_photo_7,
                R.drawable.gallery_photo_8
        };
    }
}

In onCreate function, we find the gallery by id “gallery”, and assign a ImageAdapter, which is customized BaseAdapter. The most important function in ImageAdapter is getView. Everytime, when we scroll the gallery, it will call this function to retrieve a image to show.

Download Source Code