两个片段之间的拖放视图 [英] Drag and Drop view between two Fragments

问题描述

我正在尝试在两个片段之间实现拖放。
我已经将它们添加到我的活动中，像这样

I'm currently trying to implement Drag and Drop between two Fragments. I already added them both to my Activity like this

    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.add(R.id.leftContainer, new MainActivityFragment());
    ft.add(R.id.rightContainer, new CartFragment());
    ft.commit();

我的MainActivityFragment中有几个CardViews。我想把它们拖到我的CartFragment中的ListView中。然后，在CardView被删除之后，我将添加一个新项目到此ListView。

I have several CardViews in my MainActivityFragment. I'd like to drag them over to a ListView in my CartFragment. Then I'd add a new item to this ListView after the CardView has been dropped.

我已经在MainActivityFragment中添加了此代码到目前为止

I've added this code in my MainActivityFragment so far

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View currentView = inflater.inflate(R.layout.fragment_main, container, false);

    firstProduct = (LinearLayout) currentView.findViewById(R.id.firstProduct);

    firstProduct.setOnTouchListener(new MyTouchListener());

    return currentView;
}

private final class MyTouchListener implements View.OnTouchListener {
    public boolean onTouch(View view, MotionEvent motionEvent) {
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            ClipData data = ClipData.newPlainText("", "");
            View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(view);
            view.startDrag(data, shadowBuilder, view, 0);
            return true;
        } else {
            return false;
        }
    }
}

class MyDragListener implements View.OnDragListener {
    Drawable enterShape = getResources().getDrawable(R.drawable.drag_overlay);

    @Override
    public boolean onDrag(View v, DragEvent event) {
        int action = event.getAction();
        switch (event.getAction()) {
            case DragEvent.ACTION_DRAG_STARTED:
                // do nothing
                v.setBackgroundDrawable(enterShape);

                break;
            case DragEvent.ACTION_DRAG_ENTERED:
                break;
            case DragEvent.ACTION_DRAG_EXITED:
                break;
            case DragEvent.ACTION_DROP:
                // Dropped, reassign View to ViewGroup
                View view = (View) event.getLocalState();

                view.setVisibility(View.VISIBLE);
                break;
            case DragEvent.ACTION_DRAG_ENDED:
            default:
                break;
        }
        return true;
    }
}

如果我想拖动CardView和ListView I想要放在同一个视图中，我只是说

If the CardView I want to drag and the ListView I want to drop it on would be in the same View, I'd just just say

        listView.setOnDragListener(new MyDragListener());

但由于我无法访问ListView，因为它在不同的片段，我不知道如何这样做。

But since I can't access the ListView because it's in a different Fragment I have no idea how to do this.

我已经看到这个线程两个片段之间的拖放

但是我仍然无法弄清楚。

but still I can't figure it out.

希望我描述得很好，谢谢提前！

Hope I described it well enough, thanks in advance!

推荐答案

onDrag方法必须在该片段中实现将接受DragEvent.Action_Drop的情况，然后将此方法设置为要接受放弃视图的视图（Fragment视图）

The onDrag method must be implemented inside that fragment that will be accepting the DragEvent.Action_Drop case, and then you set this method on to the view(Fragment view) that you want to accept the dropped view

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