ViewPager-带LiveData的TabLayout

Question

我在回收者视图中有一个产品列表。按下某个项目后，您将进入第二个活动，以显示与该产品有关的更多信息。我正在尝试实现viewPager。遵循CodingWithMitch的教程，但在他的示例中，他拥有随机数据，可以轻松获取它们。

ArrayList<Fragment> fragments = new ArrayList<>();
    Hat[] hats = Hats.getHats();
    for(Hat hat: hats){
        ViewPagerItemFragment fragment = ViewPagerItemFragment.getInstance(hat);
        fragments.add(fragment);
    }
    MyPagerAdapter pagerAdapter = new MyPagerAdapter(getSupportFragmentManager(), fragments);
    mMyViewPager.setAdapter(pagerAdapter);
    mTabLayout.setupWithViewPager(mMyViewPager, true);

[不幸的是，对我来说，数据是从Livedata对象获取的。如何循环或遍历实时数据以提取所有产品对象，以便设置片段！

ArrayList<Fragment> fragments = new ArrayList<>();
    final MarketViewModel marketViewModel = new ViewModelProvider(this).get(MarketViewModel.class);
    MutableLiveData<List<Product>> products = marketViewModel.getProductInfo("parentID");
    //What to do here !!!
    /*for (:) {
        ProductInfoFragment fragment = ProductInfoFragment.getInstance(products);
        fragments.add(fragment);
    }*/
    ProductPagerAdapter adapter = new ProductPagerAdapter(getSupportFragmentManager(), 0, fragments);
    viewPager.setAdapter(adapter);
    tabLayout.setupWithViewPager(viewPager, true);

也显示了整个产品。但是如何先显示按下的项目用户点击的那个。然后用户将可以左右交换整个列表！！

编辑：我尝试过这个！但现在它显示空白页。

ArrayList<Fragment> fragments = new ArrayList<>();
    final MarketViewModel marketViewModel = new ViewModelProvider(this).get(MarketViewModel.class);
    marketViewModel.getProductInfo("parentID");
    marketViewModel.getProductInfo("parentID").observe(this, products -> {
        for (int i = 0; i < products.size(); i++) {
            Product product = products.get(i);
            ProductInfoFragment fragment = ProductInfoFragment.getInstance(product);
            fragments.add(fragment);
        }
    });
    ProductPagerAdapter adapter = new ProductPagerAdapter(getSupportFragmentManager(), 0, fragments);
    viewPager.setAdapter(adapter);
    tabLayout.setupWithViewPager(viewPager, true);

Answer 1

[ViewPager提交新数据后，请尝试构建LiveData适配器，因为ViewPager似乎是用免费数据适配器初始化的，该适配器的代码在返回LiveData之前运行。

所以您可以尝试：

ArrayList<Fragment> fragments = new ArrayList<>();
    final MarketViewModel marketViewModel = new ViewModelProvider(this).get(MarketViewModel.class);
    marketViewModel.getProductInfo("parentID");
    marketViewModel.getProductInfo("parentID").observe(this, products -> {
        for (int i = 0; i < products.size(); i++) {
            Product product = products.get(i);
            ProductInfoFragment fragment = ProductInfoFragment.getInstance(product);
            fragments.add(fragment);
        }

        ProductPagerAdapter adapter = new ProductPagerAdapter(getSupportFragmentManager(), 0, fragments);
        viewPager.setAdapter(adapter);
        tabLayout.setupWithViewPager(viewPager, true);

    });