在回收站内的 cardview 中滑动图像的最佳方法是什么？

Question

我有一个 RecyclerView 和 Cardview。我想在这个 CardView 中滑动图像，就像在 OLX 应用程序中一样。最好的方法是什么？我考虑将 viewpager 放在 cardview 中。可以吗，或者我应该试试别的东西？

我用 ViewPager 做到了，但看起来太慢了。这是 viewpager 适配器的一部分。

 @Override
public Object instantiateItem(ViewGroup collection, int position) {

    LayoutInflater inflater = LayoutInflater.from(mContext);
    ViewGroup layout = (ViewGroup) inflater.inflate(R.layout.viewpager_custom, collection, false);
    collection.addView(layout);

    ImageView image = (ImageView) layout.findViewById(R.id.viewPagerImageView);
    image.setImageResource(mPics[position]);

    return layout;
}

Answer 1

我会在 GitHub 上使用以下库来实施此更改。它可以让您快速滑动并在完成后从 ListView 中删除该项目。

使用下面的示例来帮助您：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mItems = new ArrayList<>(30);
    for (int i = 0; i < 30; i++) {
        mItems.add(String.format("Card number %2d", i));
    }

    mAdapter = new CardViewAdapter(mItems);

    mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);

    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mRecyclerView.setAdapter(mAdapter);

    SwipeableRecyclerViewTouchListener swipeTouchListener =
            new SwipeableRecyclerViewTouchListener(mRecyclerView,
                    new SwipeableRecyclerViewTouchListener.SwipeListener() {
                        @Override
                        public boolean canSwipe(int position) {
                            return true;
                        }

                        @Override
                        public void onDismissedBySwipeLeft(RecyclerView recyclerView, int[] reverseSortedPositions) {
                            for (int position : reverseSortedPositions) {
                                mItems.remove(position);
                                mAdapter.notifyItemRemoved(position);
                            }
                            mAdapter.notifyDataSetChanged();
                        }

                        @Override
                        public void onDismissedBySwipeRight(RecyclerView recyclerView, int[] reverseSortedPositions) {
                            for (int position : reverseSortedPositions) {
                                mItems.remove(position);
                                mAdapter.notifyItemRemoved(position);
                            }
                            mAdapter.notifyDataSetChanged();
                        }
                    });

    mRecyclerView.addOnItemTouchListener(swipeTouchListener);

希望这对您有所帮助:)

Answer 2

你走对了。

只做一件事加载压缩位图而不是未压缩位图。您直接将位图资源设置为图像视图。要么使用像 Picasso 这样的库 https://github.com/square/picasso/

或使用 google 的官方资源来高效加载大型位图。

首先将此方法复制到您的 activity:

public static int calculateInSampleSize(
            BitmapFactory.Options options, int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {

        final int halfHeight = height / 2;
        final int halfWidth = width / 2;

        // Calculate the largest inSampleSize value that is a power of 2 and keeps both
        // height and width larger than the requested height and width.
        while ((halfHeight / inSampleSize) > reqHeight
                && (halfWidth / inSampleSize) > reqWidth) {
            inSampleSize *= 2;
        }
    }

    return inSampleSize;
}

然后这个解码位图的方法：

public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

然后像这样加载位图：

@Override
public Object instantiateItem(ViewGroup collection, int position) {

    LayoutInflater inflater = LayoutInflater.from(mContext);
    ViewGroup layout = (ViewGroup) inflater.inflate(R.layout.viewpager_custom, collection, false);
    collection.addView(layout);

    ImageView image = (ImageView) layout.findViewById(R.id.viewPagerImageView);
    image.setImageBitmap(
    decodeSampledBitmapFromResource(getResources(), R.id.myimage, reqwidth, reqheight));

    return layout;
}

在回收站内的 cardview 中滑动图像的最佳方法是什么？

What is the best way to do sliding images in cardview inside recycler?

android

android-viewpager

android-cardview

android-recyclerview