Android GridView中的图像发生了变化.怎么样？

Question

我正在为我的应用程序使用标准gridview源.我面临的问题是,当我在网格视图中滚动图像时,图像每次都会动态变化,在位置上有错误的图像.以下是我使用的代码......

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

    // Set up an array of the Thumbnail Image ID column we want
    String[] projection = {MediaStore.Images.Thumbnails._ID};
    // Create the cursor pointing to the SDCard
    cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
            projection, // Which columns to return
            null,       // Return all rows
            null,
            MediaStore.Images.Thumbnails.IMAGE_ID);
    // Get the column index of the Thumbnails Image ID
    columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);

    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) {

            // Sending image id to FullScreenActivity
            Intent i = new Intent(getApplicationContext(), ImageSelection.class);
            // passing array index
            i.putExtra("imageIndex_from_Activity", position);
            startActivity(i);

        }
    });

> ImageAdapter类

 private class ImageAdapter extends BaseAdapter {

    private Context context;

    public ImageAdapter(Context localContext) {
        context = localContext;
    }

    public int getCount() {
        return cursor.getCount();
    }
    public Object getItem(int position) {
        return position;
    }
    public long getItemId(int position) {
        return position;
    }
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView picturesView;
        if (convertView == null) {
            picturesView = new ImageView(context);
            // Move cursor to current position
            cursor.moveToPosition(position);
            // Get the current value for the requested column
            int imageID = cursor.getInt(columnIndex);
            // Set the content of the image based on the provided URI
            picturesView.setImageURI(Uri.withAppendedPath(
                    MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID));
            picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER);
            picturesView.setPadding(5, 5, 5, 5);
            picturesView.setLayoutParams(new GridView.LayoutParams(80, 80));
        }
        else {
            picturesView = (ImageView)convertView;
        }
        return picturesView;
    }
}

附加屏幕截图,1.滚动前2.向下滚动并再次向上滚动.

为什么订单会发生变化？

Answer 1

您只是在新视图上设置图像.

请执行下列操作:

if (convertView == null) {
    picturesView = new ImageView(context);
    picturesView.setScaleType(ImageView.ScaleType.FIT_CENTER);
    picturesView.setPadding(5, 5, 5, 5);
    picturesView.setLayoutParams(new GridView.LayoutParams(80, 80));    
} else {
    picturesView = (ImageView)convertView;
}
// Move cursor to current position
cursor.moveToPosition(position);
// Get the current value for the requested column
int imageID = cursor.getInt(columnIndex);
// Set the content of the image based on the provided URI
picturesView.setImageURI(Uri.withAppendedPath(
MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + imageID));