Question

I want the image to appear only at one place. When another cell is clicked the same image appears there and disappears from the previously clicked button.

public class ImageAdapter extends BaseAdapter{

        private Context mContext;

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

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

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

        public long getItemId(int position) {
            return 0;
        }

        // create a new ImageView for each item referenced by the Adapter
        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView;
            if (convertView == null) {  // if it's not recycled, initialize some attributes
                imageView = new ImageView(mContext);
                imageView.setLayoutParams(new GridView.LayoutParams(85, 85));

                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

                imageView.setPadding(0, 0, 0, 0);
            } else {
                imageView = (ImageView) convertView;
            }

            imageView.setImageResource(mThumbIds[position]);
            return imageView;
        }

    // references to our images. Here are 16 for 4x4 grid
    private Integer[] mThumbIds = {
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,

    };

}

MainActivity.java

public class MainActivity extends Activity {

    int i=0;
    long firstClick,secondClick;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //no title
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        // making it full screen
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);


        GridView gridview = (GridView) findViewById(R.id.gridview);

        gridview.setAdapter(new ImageAdapter(this));



        gridview.setOnItemClickListener(new OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> parent, View v, int position,
                    long id) {
                // TODO Auto-generated method stub

                 ImageView imageView = (ImageView) v;
                    imageView.setImageResource(R.drawable.sample_8);   
            }   
        });   
    }    
}

Answer 1

Don’t modify the ImageView from the GridView directly, instead modify the data from the adapter and call notifyDataSetChanged.

    @Override
    public void onItemClick(AdapterView<?> parent, View v, int position,
            long id) {
         if (lastClicked != -1) {
              // we previously selected a position
              mThumbs[lastClicked] = R.drawable.default_image;                  
         }
         if (lastClicked != position) {
              mThumbs[position] = R.drawable.image_required_when_grid_selected;
         }
         lastClicked = position;
         mAdapter.notifyDataSetChanged(); // mAdapter is a reference to the GridView's adapter
    }

lastClicked will be a field in your class which stores the last clicked position:

int lastClicked = -1; // -1 meaning there were no selection