Question

我想实现一个布局，我可以拖动图像并将其拖放到另一个类似于android启动器的屏幕，我们可以将应用程序图标放在一组水平滚动的屏幕上。我不知道如何开始和从哪里开始。我正在考虑实现一个比屏幕大的布局，然后在用户触摸图像时立即开始自动滚动。丢弃图像的位置将被修复。任何参考或更好的方法来实现这个？

Answer 1

将ViewPager用于多个页面。
在每个viewpager页面上的ViewPager上使用GridView（在片段中）。
viewPager上的setOnDragListener只有一次// important
在页面//重要
在ACTION_DROP上的目标GridView上获取position = pointToPosition（event.getX（），event.getY（））（在这里添加你的图标或者你移动的东西）。
ACTION_DRAG_END用于从源GridView中删除。
使用gridView中的ACTION_DRAG_EXIT将viewPager页面更改为＆amp;来回。

注意：我假设您正在使用gridView.setOnItemLongClickListener()用于startDrag（）等。请在Android网站上提及。

Answer 2

我刚刚写了这个:(它暂时工作）

只在ViewPager上添加addLragListener。您不需要在gridviews上添加DragListener。
获取Drop在目标网格上的位置。
跟踪源GridView和Target Gridview并使用它来获取其适配器。
然后在适配器之间操作Drop。



public void setDragListener() {
    pager = getViewPager();

    dragListener = new View.OnDragListener() {
        GridViewAdapter sourceAdapter = null;
        GridViewAdapter targetAdapter = null;
        int currentOffset = 0;

        @Override
        public boolean onDrag(View v, DragEvent event) {
            int currentX = -1;
            int currentY = -1;

            switch (event.getAction()) {
                case DragEvent.ACTION_DRAG_STARTED:
                    if (!pager.isFakeDragging()) {
                        pager.beginFakeDrag();
                    }
                    break;
                case DragEvent.ACTION_DRAG_ENTERED:
                    pager.setCurrentItem(pager.getCurrentItem());
                    currentOffset = (int) (event.getX());
                    if (!pager.isFakeDragging()) {
                        pager.beginFakeDrag();
                    }
                    break;
                case DragEvent.ACTION_DRAG_EXITED:
                    break;
                case DragEvent.ACTION_DRAG_LOCATION:
                    if (pager != null) {
                        if (!pager.isFakeDragging()) {
                            pager.beginFakeDrag();
                        }
                        if (pager.isFakeDragging()) {
                            int maxWidth = pager.getWidth() * pager.getCount();
                            int offset = (int) (event.getX());
                            int scrollX = getScrollX();
                            int dragBy = (int) -1 * (offset - currentOffset);
                            currentOffset = offset;
                            pager.fakeDragBy(dragBy * pager.getCount());
                            int  scrolledPage = (int) (offset + scrollX) / pager.getWidth();
                            if (pager.getCurrentItem() != scrolledPage) {
                                pager.setCurrentItem(Math.abs(scrolledPage));
                            }
                        }
                    }
                    break;
                case DragEvent.ACTION_DRAG_ENDED:
                    if (pager.isFakeDragging()) {
                        pager.endFakeDrag();
                    }
                    break;
                case DragEvent.ACTION_DROP:
                    if (pager.isFakeDragging()) {
                        pager.endFakeDrag();
                    }
                    currentX = (int) event.getX();
                    currentY = (int) event.getY();

                    // u can use meta data and other info which u passed when longPress
                    // u can set sourcePage and sourcePosition in meta data.

                    metaMove = event.getLocalState(); 

                    sourceAdapter = // get Source Gridviews adapter
                    targetAdapter = // get Target GridViews Adapter ie current Page's gridviews adapter.
                    GridView g = // get The gridview current Page gridview
                    if (g != null) {
                        int position = g.pointToPosition(currentX + (getScrollX() - (pager.getWidth() * pager.getCurrentItem())), currentY);
                        metaMove.targetPosition = position;
                        metaMove.targetPage = currentPage;
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                // u can move from source to target by inset and remove.
                                // use some broadcast function to reset if page does not have any item left while moving. Ur logic here.
                                move(sourceAdapter, targetAdapter, metaMove);
                            }
                        });
                    }
                    break;
                default:
                    break;
            }
            return true;
        }
    };
    pager.setOnDragListener(dragListener);
}

public int getScrollX() { 
      int maxWidth = pager.getWidth() * pager.getCount();
      int scrollX = pager.getScrollX();
                      if (pager.getScrollX() < 0) {
                            scrollX = maxWidth + scrollX - pager.getWidth();
                        } else if (pager.getScrollX() == 0) {
                            if (pager.getCurrentItem() == (pager.getCount() - 1)) {
                                scrollX = maxWidth + scrollX - pager.getWidth();
                            }
                        }
   return scrollX;
}


Use following onLongPress on your sourceGrid:

                metaMove.sourcePage = // sourcePage;
                metaMove.sourcePosition = position;
                metaMove.targetPosition = -1; // to be set on drop
                metaMove.targetPage = -1 // to be set on drop;

                boolean dragStarted = view.startDrag(null, 
                        myShadow,  
                        metaMove,  
                        0          
                );

public void setDragListener() { pager = getViewPager(); dragListener = new View.OnDragListener() { GridViewAdapter sourceAdapter = null; GridViewAdapter targetAdapter = null; int currentOffset = 0; @Override public boolean onDrag(View v, DragEvent event) { int currentX = -1; int currentY = -1; switch (event.getAction()) { case DragEvent.ACTION_DRAG_STARTED: if (!pager.isFakeDragging()) { pager.beginFakeDrag(); } break; case DragEvent.ACTION_DRAG_ENTERED: pager.setCurrentItem(pager.getCurrentItem()); currentOffset = (int) (event.getX()); if (!pager.isFakeDragging()) { pager.beginFakeDrag(); } break; case DragEvent.ACTION_DRAG_EXITED: break; case DragEvent.ACTION_DRAG_LOCATION: if (pager != null) { if (!pager.isFakeDragging()) { pager.beginFakeDrag(); } if (pager.isFakeDragging()) { int maxWidth = pager.getWidth() * pager.getCount(); int offset = (int) (event.getX()); int scrollX = getScrollX(); int dragBy = (int) -1 * (offset - currentOffset); currentOffset = offset; pager.fakeDragBy(dragBy * pager.getCount()); int scrolledPage = (int) (offset + scrollX) / pager.getWidth(); if (pager.getCurrentItem() != scrolledPage) { pager.setCurrentItem(Math.abs(scrolledPage)); } } } break; case DragEvent.ACTION_DRAG_ENDED: if (pager.isFakeDragging()) { pager.endFakeDrag(); } break; case DragEvent.ACTION_DROP: if (pager.isFakeDragging()) { pager.endFakeDrag(); } currentX = (int) event.getX(); currentY = (int) event.getY(); // u can use meta data and other info which u passed when longPress // u can set sourcePage and sourcePosition in meta data. metaMove = event.getLocalState(); sourceAdapter = // get Source Gridviews adapter targetAdapter = // get Target GridViews Adapter ie current Page's gridviews adapter. GridView g = // get The gridview current Page gridview if (g != null) { int position = g.pointToPosition(currentX + (getScrollX() - (pager.getWidth() * pager.getCurrentItem())), currentY); metaMove.targetPosition = position; metaMove.targetPage = currentPage; getActivity().runOnUiThread(new Runnable() { @Override public void run() { // u can move from source to target by inset and remove. // use some broadcast function to reset if page does not have any item left while moving. Ur logic here. move(sourceAdapter, targetAdapter, metaMove); } }); } break; default: break; } return true; } }; pager.setOnDragListener(dragListener); } public int getScrollX() { int maxWidth = pager.getWidth() * pager.getCount(); int scrollX = pager.getScrollX(); if (pager.getScrollX() < 0) { scrollX = maxWidth + scrollX - pager.getWidth(); } else if (pager.getScrollX() == 0) { if (pager.getCurrentItem() == (pager.getCount() - 1)) { scrollX = maxWidth + scrollX - pager.getWidth(); } } return scrollX; }

创建启动器，就像在android中拖放多个屏幕一样

2 个答案: