我目前正在努力发送包含包含列表的对象的意图。
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。
事情是，我可以通过调用例如在RecipeActivity中获取成分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中获取对象的正确索引）
提前致谢！
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);
}
}
成分.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);
}
}
RecipeDetails活动
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();
}
}
成分适配器
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();
}
}
最佳答案
我建议您在Recipe recipes公共静态变量内设置RecipeDetailsActivity变量。就像public static Recipe recipes。当您打开“详细”活动时，如下所示：RecipeDetailsActivity.recipes = recipes.get(adapterPosition);在这种情况下，这将是一个更简单的解决方案。
关于java - 使用具有List <Object>的List <Object>发送 Intent ，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/61082766/