Firebase:从 Firebase 中提取随机数据到 RecyclerView (android) [英] Firebase: Pull random data from Firebase to RecyclerView (android)

问题描述

我做了一个查询，只从 RecyclerView 内的数据库中提取 6 个 itens，但此时我只能 orderByChild、limitToFirst 或 last.一切正常，但...

I made a query to pull only 6 itens from database inside a RecyclerView, but at this time I can only orderByChild, limitToFirst or last. Everything is working fine but...

每次刷新活动时，我都想将 Random itens 放入 Recyclerview 中.

I'd like to put Random itens inside the Recyclerview every time I refresh the activity.

如何将随机数据放入 RecyclerView?Firebase 没有特殊的随机查询.还有其他方法吗?

How can I put random data inside RecyclerView? Firebase does not have a special Random query. Is there any other way to do it?

这是我的代码:

mDatabase = FirebaseDatabase.getInstance().getReference().child("Category");
query = mDatabase.limitToFirst(6); 

@Override
        protected void populateViewHolder(final CategoryViewHolder viewHolder, Category model, int position) {


            viewHolder.setImage(getApplicationContext(), model.getImagem());


            viewHolder.mView.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {


         });


        }


    };


    mImagesList.setAdapter(firebaseRecyclerAdapter);

}

我的适配器:

public static class CategoryViewHolder extends RecyclerView.ViewHolder {

    View mView;

    public CategoryViewHolder(View itemView) {
        super(itemView);

        mView = itemView;
    }

    public void setImage(Context ctx, String image1) {

        ImageView image = (ImageView) mView.findViewById(R.id.photo);
        Picasso.with(ctx).load(image1).into(image);

    }
}

推荐答案

我建议您还向 Model 类添加另一个变量.类似于id"的东西.并且您将随机的 Long 值存储在其中.(例如从 0 到 15).然后创建一个将生成随机值的方法(假设该方法的名称是 generateRandom()).这样，当你想获得随机数据时，你可以像这样使用你的查询:

I suggest you also add another variable to your Model class. Something like an "id". And you store random Long values in it. (From 0 to 15 for example). And then create a method that will generate a random value (lets say the method's name is generateRandom()). This way, when you want to get the random data, you can use your query like this:

query = mDatabase.orderByChild("id").startAt(generateRandom()).limitToFirst(6); 

这篇关于Firebase:从 Firebase 中提取随机数据到 RecyclerView (android)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！