Question

我希望图片只出现在一个地方。单击另一个单元格时，同一图像将显示在此处，并从之前单击的按钮中消失。

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

请勿直接修改ImageView中的GridView，而是修改适配器中的数据并调用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将是您班级中存储最后点击位置的字段：

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

如何在单击另一个单元格时更改GridView单元格的图像？

1 个答案: