android - ListView 图像在滚动期间发生变化

Question

我尝试用动态图像制作 ListView ，使用 asynctask 下载图像并设置到 ListView 中。我的问题是向下滚动时图像会随机更改..

class ps1 extends ArrayAdapter<String> {
    Context context;
    String[] images1;
    List mList;
    String[] namearray;
    String[] rating;

    static class ViewHolder {
        ImageView localImageView1;
        ImageView localImageView2;
        ImageView localImageView3;
    }

    ps1(Context paramContext, String[] paramArrayOfString1, String[] paramArrayOfString2, String[] paramArrayOfString3) {
        super(paramContext, R.layout.list2, R.id.imageView1, paramArrayOfString1);
        this.context = paramContext;
        this.images1 = paramArrayOfString3;
        this.namearray = paramArrayOfString1;
        this.rating = paramArrayOfString2;
    }

    public View getView(int paramInt, View paramView, ViewGroup paramViewGroup) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(context.LAYOUT_INFLATER_SERVICE);

    ViewHolder viewHolder = new ViewHolder();
    if (paramView == null) {
        paramView = inflater.inflate(R.layout.list2, paramViewGroup, false);

    }


    viewHolder.localImageView1 = (ImageView) paramView
            .findViewById(R.id.imageView1);
    viewHolder.localImageView2 = (ImageView) paramView
            .findViewById(R.id.imageView2);
    viewHolder.localImageView3 = (ImageView) paramView
            .findViewById(R.id.imageView3);


    viewHolder.localImageView1.setScaleType(ImageView.ScaleType.FIT_XY);
    viewHolder.localImageView2.setScaleType(ImageView.ScaleType.FIT_XY);
    viewHolder.localImageView3.setScaleType(ImageView.ScaleType.FIT_XY);

    viewHolder.localImageView1.setTag(this.namearray[paramInt]);
    new LoadImage().execute(viewHolder.localImageView1);
    viewHolder.localImageView2.setTag(this.rating[paramInt]);
    new LoadImage().execute(viewHolder.localImageView2);
    viewHolder.localImageView3.setTag(this.images1[paramInt]);
    new LoadImage().execute(viewHolder.localImageView3);


    return paramView;
    }
    }

    class LoadImage extends AsyncTask<Object, Void, Bitmap> {
    private ImageView imv;

    private Bitmap download_Image(String paramString) {
    Bitmap localBitmap = null;
    try {
        Object localObject = null;
        localBitmap = BitmapFactory
                .decodeStream(((HttpURLConnection) new URL(paramString)
                        .openConnection()).getInputStream());
        localObject = localBitmap;
        if (localObject != null) {
            return localBitmap;
        }
    } catch (Exception e) {

    }
    return localBitmap;
    }

    protected Bitmap doInBackground(Object... paramVarArgs) {
    this.imv = ((ImageView) paramVarArgs[0]);
    Log.d("fsdf", (String) this.imv.getTag());
    return download_Image((String) this.imv.getTag());
    }

    protected void onPostExecute(Bitmap paramBitmap) {
    this.imv.setImageBitmap(paramBitmap);
    }
}

Answer 1

我也有过同样的经历。我也在寻找合适的解决方案。据我搜索，我了解到 ListView 会在向下滚动时清除先前的 View ，并在您向后滚动时重新加载它。因此，在上下滚动时，您的图像可能会重新循环和错位。 (我也在等待正确的解决方案)。

但我已经使用 SmartImageView 解决了它，这是一个直接下载图像并将其设置到 ImageView 的库。它将在缓存中维护图像，因此您可以获得正确的图像。

相比之下，这也更快。