Question

我想展示我的披萨＆amp; amp;从Web服务器中提取对象，但我的RecyclerView仅直接加载图像，而Scroll上的TextViews。我为每个适配器调用notifyDataSetChanged（），甚至通过迭代通知适配器每个项目。我正在使用Glide来改变我的形象。

为什么我的TextViews没有加载？

MainActivity.java

public class MainActivity extends AppCompatActivity {

    RecyclerView recyclerView;
    PizzaDataAdapter pizzaDataAdapter;
    DrinkDataAdapter drinkDataAdapter;
    CartDataAdapter cartDataAdapter;
    ImageView emptyListImageView;
    TextView emptyListTextView;
    Toolbar mActionBarToolbar;
    ConstraintLayout cartIntLayout;
    RecyclerView product_recyclerview;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_food:
                    mActionBarToolbar.setTitle("Pizzas");
                    FrameLayout pizzas_layout = findViewById(R.id.pizzas_layout);
                    FrameLayout drinks_layout = findViewById(R.id.drinks_layout);
                    ConstraintLayout cart_layout = findViewById(R.id.cart_layout);
                    drinks_layout.setVisibility(GONE);
                    cart_layout.setVisibility(GONE);
                    pizzas_layout.setVisibility(View.VISIBLE);
                    return true;
                case R.id.navigation_drinks:
                    mActionBarToolbar.setTitle("Drinks");
                    drinks_layout = findViewById(R.id.drinks_layout);
                    pizzas_layout = findViewById(R.id.pizzas_layout);
                    cart_layout = findViewById(R.id.cart_layout);

                    pizzas_layout.setVisibility(GONE);
                    cart_layout.setVisibility(GONE);
                    drinks_layout.setVisibility(View.VISIBLE);
                    return true;
                case R.id.navigation_cart:
                    mActionBarToolbar.setTitle("Cart");
                    pizzas_layout = findViewById(R.id.pizzas_layout);
                    drinks_layout = findViewById(R.id.drinks_layout);
                    cart_layout = findViewById(R.id.cart_layout);

                    initCartViews();
                    pizzas_layout.setVisibility(GONE);
                    drinks_layout.setVisibility(GONE);
                    cart_layout.setVisibility(View.VISIBLE);
                    return true;
            }
            return false;
        }
    };

    public static void start(Context context) {
        Intent starter = new Intent(context, MainActivity.class);
        context.startActivity(starter);
    }

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

        cartIntLayout = findViewById(R.id.cart_int_layout);
        cartIntLayout.bringToFront();
        mActionBarToolbar = findViewById(R.id.my_toolbar);
        mActionBarToolbar.setTitle("Pizzas");
        mActionBarToolbar.setTitleTextColor(getResources().getColor(R.color.white, this.getTheme()));
        setSupportActionBar(mActionBarToolbar);

        BottomNavigationView navigation = findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

        PizzaLoadingTask.TaskListener pizzaListener = new PizzaLoadingTask.TaskListener() {
            @Override
            public void onComplete(List<Pizza> pizzas) {
                if (pizzas.isEmpty()) {
                    initViewsWithEmptyList();
                }
                initPizzaViews(pizzas);
            }
        };
        new PizzaLoadingTask(pizzaListener, APIClient.getInstance()).execute();

        DrinkLoadingTask.TaskListener drinkListener = new DrinkLoadingTask.TaskListener() {
            @Override
            public void onComplete(List<Drink> drinks) {
                if (drinks.isEmpty()) {
                    initViewsWithEmptyList();
                }
                initDrinkViews(drinks);
            }
        };
        new DrinkLoadingTask(drinkListener, APIClient.getInstance()).execute();

    }

    private void initPizzaViews(List<Pizza> pizzas) {
        pizzaDataAdapter = new PizzaDataAdapter(pizzas);
        recyclerView = findViewById(R.id.card_recycler_view_pizzas);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);

        recyclerView.addItemDecoration(new DividerItemDecoration(getBaseContext(),
                DividerItemDecoration.VERTICAL));
        pizzaDataAdapter.notifyDataSetChanged();
        recyclerView.setAdapter(pizzaDataAdapter);
    }

    private void initDrinkViews(List<Drink> drinks) {
        recyclerView = findViewById(R.id.card_recycler_view_drinks);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);

        recyclerView.addItemDecoration(new DividerItemDecoration(getBaseContext(),
                DividerItemDecoration.VERTICAL));
        drinkDataAdapter = new DrinkDataAdapter(drinks);
        drinkDataAdapter.notifyDataSetChanged();
        recyclerView.setAdapter(drinkDataAdapter);
    }

    private void initCartViews() {
        product_recyclerview = findViewById(R.id.cart_products_recyclerview);
        product_recyclerview.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        product_recyclerview.setLayoutManager(layoutManager);
        cartDataAdapter = new CartDataAdapter(pizzaDataAdapter.getCartPizzas(), drinkDataAdapter.getCartDrinks());
        product_recyclerview.setAdapter(cartDataAdapter);

    }

    private void initViewsWithEmptyList() {
        recyclerView = findViewById(R.id.card_recycler_view_drinks);
        recyclerView.setVisibility(GONE);
        emptyListImageView = findViewById(R.id.pizza_image_empty_list);
        emptyListTextView = findViewById(R.id.pizza_empty_textview);
        emptyListImageView.setVisibility(View.VISIBLE);
        emptyListTextView.setVisibility(View.VISIBLE);
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        SharedPreferences preferences = getSharedPreferences("loginRecognizer", MODE_PRIVATE);
        if (preferences.contains("loggedIn")) {
            Intent i = new Intent(this, LoginActivity.class); // Your list's Intent
            i.setFlags(i.getFlags() | Intent.FLAG_ACTIVITY_NO_HISTORY); // Adds the FLAG_ACTIVITY_NO_HISTORY flag
            startActivity(i);
        }
    }
}

PizzaDataAdapter.java（DrinkDataAdapter与Drink-Objects相同）

public class PizzaDataAdapter extends RecyclerView.Adapter<PizzaDataAdapter.ViewHolder> {
    private List<Pizza> pizzas;
    //TODO implement cartDrinks LinkedList
    private List<Pizza> cartPizzas = new LinkedList<>();

    PizzaDataAdapter(List<Pizza> pizzas) {
        this.pizzas = pizzas;
    }

    private static BigDecimal round(float d) {
        BigDecimal bd = new BigDecimal(Float.toString(d));
        bd = bd.setScale(2, BigDecimal.ROUND_HALF_UP);
        return bd;
    }

    @Override
    public PizzaDataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.pizza_card_row, viewGroup, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(PizzaDataAdapter.ViewHolder viewHolder, int position) {

        final Pizza pizza = pizzas.get(position);

        // viewHolder.setIsRecyclable(false);

        //viewHolder.pizza_image.setText(pizzas.get(i).getId().toString());
        viewHolder.pizza_name.setText(pizza.getName());
        BigDecimal result = round(pizza.getPrice());
        String price = "Price: " + result.toString();
        viewHolder.pizza_price.setText(price);

        GlideApp.with(viewHolder.pizza_image.getContext())
                .load(pizzas.get(position).getImagepath())
                .apply(RequestOptions.circleCropTransform())
                .into(viewHolder.pizza_image);

        viewHolder.pizza_layout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(viewHolder.pizza_layout.getContext(), PizzaDetailActivity.class);
                intent.putExtra("Name", pizzas.get(position).getName());
                intent.putExtra("Price", pizzas.get(position).getPrice());
                intent.putExtra("Ingredients", pizzas.get(position).getIngredients());
                viewHolder.pizza_layout.getContext().startActivity(intent);
            }
        });

        viewHolder.plus_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                cartPizzas.add(pizzas.get(position));
            }
        });

    }

    @Override
    public int getItemCount() {
        return pizzas.size();
    }

    public List<Pizza> getCartPizzas() {
        return cartPizzas;
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        private ImageView pizza_image;
        private TextView pizza_name, pizza_price;
        private ImageButton plus_button;
        private ConstraintLayout pizza_layout;

        ViewHolder(View view) {
            super(view);

            pizza_image = view.findViewById(R.id.pizza_image);

            pizza_name = view.findViewById(R.id.pizza_name);
            pizza_price = view.findViewById(R.id.pizza_price);
            plus_button = view.findViewById(R.id.pizza_plus_button);
            pizza_layout = view.findViewById(R.id.pizza_card_row_layout);
        }
    }
}

PizzaLoadingTask.java

public class PizzaLoadingTask extends AsyncTask<Void, Void, List<Pizza>> {

    private APIClient apiClient;
    private TaskListener mListener;

    public PizzaLoadingTask(TaskListener listener, APIClient apiClient){
        this.mListener=listener;
        this.apiClient = apiClient;
    }

    @Override
    protected List<Pizza> doInBackground(Void... voids) {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(APIInterface.baseUrl)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
        APIInterface request = retrofit.create(APIInterface.class);
        Call<List<Pizza>> call = request.getPizzas();

        try {
            Response<List<Pizza>> jsonResponse = call.execute();
            return jsonResponse.body();
            // return Collections.emptyList();
        } catch (IOException | NullPointerException e) {
            e.printStackTrace();
            return Collections.emptyList();
        }
    }

    @Override
    protected void onPostExecute(List<Pizza> pizzas) {
        mListener.onComplete(pizzas);
    }

    public interface TaskListener {
        void onComplete(List<Pizza> pizzas);
    }
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".screens.MainActivity">

    <android.support.v7.widget.Toolbar
        android:id="@+id/my_toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:elevation="4dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

    <android.support.constraint.ConstraintLayout
        android:id="@+id/navigation_layout"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toTopOf="@+id/navigation"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar"
        app:layout_constraintVertical_bias="0.0">

        <include
            android:id="@+id/pizzas_layout"
            layout="@layout/pizza_products"
            android:visibility="visible" />

        <include
            android:id="@+id/drinks_layout"
            layout="@layout/drink_products"
            android:visibility="invisible" />

        <include
            android:id="@id/cart_layout"
            layout="@layout/product_cart"
            android:visibility="invisible" />

    </android.support.constraint.ConstraintLayout>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="0dp"
        android:layout_marginStart="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/navigation">

    </android.support.design.widget.BottomNavigationView>

    <android.support.constraint.ConstraintLayout
        android:id="@+id/cart_int_layout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="57dp"
        android:layout_marginTop="8dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@id/navigation">

        <TextView
            android:id="@+id/cart_int_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1"
            android:textColor="#000000"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    </android.support.constraint.ConstraintLayout>

</android.support.constraint.ConstraintLayout>

pizza_products.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pizza_products_layout"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.apprentice.ti8m.myfirstrestclient.screens.MainActivity">


    <android.support.v7.widget.RecyclerView
        android:id="@+id/card_recycler_view_pizzas"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        tools:layout_editor_absoluteX="8dp"
        tools:layout_editor_absoluteY="8dp"
        tools:listitem="@layout/pizza_card_row">

    </android.support.v7.widget.RecyclerView>

    <android.support.constraint.ConstraintLayout
        android:id="@+id/pizza_image_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center">

        <ImageView
            android:id="@+id/pizza_image_empty_list"
            android:layout_width="256dp"
            android:layout_height="256dp"
            android:layout_marginEnd="8dp"
            android:layout_marginStart="8dp"
            android:visibility="gone"
            app:layout_constraintBottom_toTopOf="@+id/pizza_empty_textview"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.176"
            app:layout_constraintVertical_chainStyle="spread"
            app:srcCompat="@drawable/ic_pizza_empty_list"
            tools:visibility="visible"
            android:contentDescription="@string/image_to_show_up_if_pizza_list_is_empty" />

        <TextView
            android:id="@+id/pizza_empty_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/pizza_list_empty"
            android:visibility="gone"
            android:textSize="24sp"
            android:textStyle="bold"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/pizza_image_empty_list"
            app:layout_constraintVertical_bias="0.567"
            tools:visibility="visible" />
    </android.support.constraint.ConstraintLayout>
</FrameLayout>

pizza_card_row.xml

<android.support.constraint.ConstraintLayout
    android:id="@+id/pizza_card_row_layout"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="72dp">


    <ImageView
        android:id="@+id/pizza_image"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:adjustViewBounds="true"
        android:scaleType="centerCrop"
        android:layout_marginStart="16dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        tools:ignore="ContentDescription" />

    <TextView
        android:id="@+id/pizza_name"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginTop="0dp"
        android:fontFamily="sans-serif"
        android:textSize="16sp"
        android:textColor="@color/colorPizzaName"
        app:layout_constraintHorizontal_bias="0.1"
        app:layout_constraintLeft_toRightOf="@+id/pizza_image"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="@+id/pizza_image" />

    <TextView
        android:id="@+id/pizza_price"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginBottom="-1dp"
        app:layout_constraintBottom_toBottomOf="@+id/pizza_image"
        app:layout_constraintLeft_toRightOf="@+id/pizza_image"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:fontFamily="sans-serif"
        android:textSize="14sp"
        app:layout_constraintRight_toRightOf="parent" />

    <ImageButton
        android:id="@+id/pizza_plus_button"
        style="@style/Widget.AppCompat.Button.Borderless"
        android:layout_width="72dp"
        android:layout_height="0dp"
        android:layout_gravity="center"
        android:src="@drawable/ic_add_black_24dp"
        android:gravity="center"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:contentDescription="@string/plus_button_for_each_recyclerview_card" />

</android.support.constraint.ConstraintLayout>

Answer 1

尝试删除此不必要的代码： j

因为在适配器

中完成/加载数据后设置了recyclerview适配器

RecyclerView正在加载图像，但滚动时TextView

1 个答案: