具有列表的发送意图具有列表

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我目前正在努力发送一个包含列表的Object的意图。基本上，我可以将正确的数据发送到另一个活动，但是我无法在数据中获取列表。抱歉，我真的不知道该如何形容。

事实是，我可以通过调用例如在RecipeActivity中获取配料recipes.get(0).getIngredients()，但是在RecipeDetailsActivity中，由于列表为空，因此出现错误。 （而且我也不知道如何在DetailsActivity中获得对象的正确索引）

提前感谢！

Recipe.java

public class Recipe implements Parcelable 
@SerializedName("id")
@Expose
private Integer mId;
@SerializedName("name")
@Expose
private String mName;
@SerializedName("ingredients")
@Expose
private List<Ingredient> mIngredients = null;
@SerializedName("steps")
@Expose
private List<Step> mSteps = null;
@SerializedName("servings")
@Expose
private Integer mServings;
@SerializedName("image")
@Expose
private String mImage;

protected Recipe(Parcel in) 
    if (in.readByte() == 0) 
        mId = null;
     else 
        mId = in.readInt();
    
    mName = in.readString();
    if (in.readByte() == 0) 
        mServings = null;
     else 
        mServings = in.readInt();
    
    mImage = in.readString();


public static final Creator<Recipe> CREATOR = new Creator<Recipe>() 
    @Override
    public Recipe createFromParcel(Parcel in) 
        return new Recipe(in);
    

    @Override
    public Recipe[] newArray(int size) 
        return new Recipe[size];
    
;

public Integer getId() 
    return mId;


public void setId(Integer id) 
    mId = id;


public String getName() 
    return mName;


public void setName(String name) 
    mName = name;


public List<Ingredient> getIngredients() 
    return mIngredients;


public void setIngredients(List<Ingredient> ingredients) 
    mIngredients = ingredients;


public List<Step> getSteps() 
    return mSteps;


public void setSteps(List<Step> steps) 
    mSteps = steps;


public Integer getServings() 
    return mServings;


public void setServings(Integer servings) 
    mServings = servings;


public String getImage() 
    return mImage;


public void setImage(String image) 
    mImage = image;


@Override
public int describeContents() 
    return 0;


@Override
public void writeToParcel(Parcel dest, int flags) 
    if (mId == null) 
        dest.writeByte((byte) 0);
     else 
        dest.writeByte((byte) 1);
        dest.writeInt(mId);
    
    dest.writeString(mName);
    if (mServings == null) 
        dest.writeByte((byte) 0);
     else 
        dest.writeByte((byte) 1);
        dest.writeInt(mServings);
    
    dest.writeString(mImage);

Ingredient.java

public class Ingredient 

@SerializedName("quantity")
@Expose
private Double mQuantity;
@SerializedName("measure")
@Expose
private String mMeasure;
@SerializedName("ingredient")
@Expose
private String mIngredient;

public Double getQuantity() 
    return mQuantity;


public void setQuantity(Double quantity) 
    mQuantity = quantity;


public String getMeasure() 
    return mMeasure;


public void setMeasure(String measure) 
    mMeasure = measure;


public String getIngredient() 
    return mIngredient;


public void setIngredient(String ingredient) 
    mIngredient = ingredient;

RecipeActivity

public class RecipeActivity extends AppCompatActivity implements RecipeAdapter.RecipeAdapterOnClickHandler
private static final String TAG = RecipeActivity.class.getSimpleName();

@BindView(R.id.recipe_recycler_view)
RecyclerView mRecyclerView;

private RecipeAdapter mRecipeAdapter;
private List<Recipe> recipes;

public static final String MY_RECIPE = "myRecipe";

@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recipe);

    RecipeService service = RecipeClient.getRetrofit().create(RecipeService.class);

    Call<List<Recipe>> call = service.getAllRecipes();
    call.enqueue(new Callback<List<Recipe>>() 
        @Override
        public void onResponse(Call<List<Recipe>> call, Response<List<Recipe>> response) 
            if (response.isSuccessful()) 
                recipes = response.body();
                generateDataList(recipes);
            
        

        @Override
        public void onFailure(Call<List<Recipe>> call, Throwable t) 
            Toast.makeText(RecipeActivity.this, "Something went wrong...Please try later!", Toast.LENGTH_SHORT).show();
            Log.v(TAG, t.toString());
        
    );


private void generateDataList(List<Recipe> recipeList) 
    ButterKnife.bind(this);
    mRecipeAdapter = new RecipeAdapter(this, recipeList, RecipeActivity.this);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(RecipeActivity.this);
    mRecyclerView.setLayoutManager(layoutManager);
    mRecyclerView.setAdapter(mRecipeAdapter);



@Override
public void onClick(int adapterPosition) 
    Context context = this;
    Class detailClass = RecipeDetailsActivity.class;

    Intent detailsIntent = new Intent(context, detailClass);
    detailsIntent.putExtra(MY_RECIPE, recipes.get(adapterPosition));
    startActivity(detailsIntent);

RecipeDetailsActivity

public class RecipeDetailsActivity extends AppCompatActivity implements IngredientAdapter.IngredientAdapterOnClickHandler
private static final String TAG = RecipeDetailsActivity.class.getSimpleName();

private Recipe recipes;
private List<Recipe> recipeList;

private String recipeName;
private String ingredient;
private Double quantity;
private String measure;
private List<Ingredient> ingredientList = new ArrayList<>();
IngredientAdapter mAdapter;

@Nullable
@BindView(R.id.ingredients)
TextView ingredientsTV;
@Nullable
@BindView(R.id.quantity)
TextView quantityTV;
@BindView(R.id. recipe_details_rv)
RecyclerView mRecyclerView;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recipe_details);

    Intent intentToCatch = getIntent();
    recipes = intentToCatch.getParcelableExtra(RecipeActivity.MY_RECIPE);

    recipeName = recipes.getName();
    ingredientList = recipes.getIngredients();
    if (ingredientList != null) 
        ingredient = ingredientList.get(0).getIngredient();
        quantity = ingredientList.get(0).getQuantity();
        measure = ingredientList.get(0).getMeasure();
     else 
        Log.v(TAG, "FAILING LOADING INGREDIENTSLIST");
    
    setTitle(recipeName);

    ButterKnife.bind(this);

    mAdapter = new IngredientAdapter(this, ingredientList, RecipeDetailsActivity.this);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(RecipeDetailsActivity.this);
    mRecyclerView.setLayoutManager(layoutManager);
    mRecyclerView.setAdapter(mAdapter);



@Override
public void onClick(int adapterPosition)

RecipeAdapter

public class RecipeAdapter extends RecyclerView.Adapter<RecipeAdapter.RecipeAdapterViewHolder> 

private List<Recipe> mRecipeList;
private Context mContext;
private RecipeAdapterOnClickHandler mOnClickHandler;

public RecipeAdapter(Context context, List<Recipe> recipeList, RecipeAdapterOnClickHandler onClickHandler) 
    mContext = context;
    mRecipeList = recipeList;
    mOnClickHandler = onClickHandler;


public interface RecipeAdapterOnClickHandler 
    void onClick(int adapterPosition);


public class RecipeAdapterViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    @BindView(R.id.recipe_name)
    TextView mRecipeName;

    public RecipeAdapterViewHolder(@NonNull View itemView) 
        super(itemView);
        itemView.setOnClickListener(this);
        ButterKnife.bind(this, itemView);
    

    @Override
    public void onClick(View v) 
        int adapterPosition = getAdapterPosition();
        mOnClickHandler.onClick(adapterPosition);
    



@NonNull
@Override
public RecipeAdapterViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) 
    LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
    View view = layoutInflater.inflate(R.layout.recipe_list_item, parent, false);
    return new RecipeAdapterViewHolder(view);


@Override
public void onBindViewHolder(@NonNull RecipeAdapterViewHolder holder, int position) 
    holder.mRecipeName.setText(mRecipeList.get(position).getName());


@Override
public int getItemCount() 
    if (mRecipeList == null) 
        return 0;
    
    return mRecipeList.size();

IngredientAdapter

public class IngredientAdapter extends RecyclerView.Adapter<IngredientAdapter.IngredientAdapterViewHolder> 

private List<Ingredient> mIngredient;
private Context mContext;
private IngredientAdapterOnClickHandler mOnClickHandler;

public IngredientAdapter(Context context, List<Ingredient> ingredientList, IngredientAdapterOnClickHandler onClickHandler) 
    mContext = context;
    mIngredient = ingredientList;
    mOnClickHandler = onClickHandler;


public interface IngredientAdapterOnClickHandler 
    void onClick(int adapterPosition);


public class IngredientAdapterViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    @BindView(R.id.ingredients)
    TextView ingredientTextView;
    @BindView(R.id.step_description)
    TextView stepsDescriptionTextView;
    @BindView(R.id.quantity)
    TextView quantityDescriptionTextView;

    public IngredientAdapterViewHolder(@NonNull View itemView) 
        super(itemView);
        ButterKnife.bind(this, itemView);
    

    @Override
    public void onClick(View v) 
        int adapterPosition = getAdapterPosition();
        mOnClickHandler.onClick(adapterPosition);
    


@NonNull
@Override
public IngredientAdapterViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) 
    LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
    View view = layoutInflater.inflate(R.layout.recipe_details_list_item, parent, false);
    return new IngredientAdapterViewHolder(view);


@Override
public void onBindViewHolder(@NonNull IngredientAdapterViewHolder holder, int position) 
    holder.ingredientTextView.setText(mIngredient.get(position).getIngredient());
    holder.stepsDescriptionTextView.setText(mIngredient.get(position).getQuantity().toString());
    holder.quantityDescriptionTextView.setText(mIngredient.get(position).getMeasure());



@Override
public int getItemCount() 
    if (mIngredient == null) 
        return 0;
    
    return mIngredient.size();

答案

我建议您将Recipe recipes变量放在RecipeDetailsActivity公共静态变量内。像public static Recipe recipes。当您打开“详细”活动时，就像这样：RecipeDetailsActivity.recipes = recipes.get(adapterPosition);在这种情况下，这将是一个更简单的解决方案。

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