[英]How to convert a Android SqlBrite model class to implement Parcelable
我正在構建一個應用程序,其中我使用SQLBrite sql包裝器執行所有數據庫操作。 另外,我正在使用“自動值”通過Google AutoValue庫自動處理我的所有getter和setter。
現在,我的問題是處理設備旋轉並處理我的putParcelable()方法需要兩個參數,其中第一個是KEY,第二個是Parcelable類型的值。 如前所述,我的Recipe類(下面的代碼)是SQLBrite實現的類,並且未實現Parcelable。 我想要一些幫助將其轉換為實現Parcelable接口。
@AutoValue
public abstract class Recipe {
public abstract int id();
public abstract String name();
public abstract List<Ingredients> ingredients();
public abstract List<Step> steps();
public abstract int servings();
public abstract String image();
public static Builder builder() {
return new AutoValue_Recipe.Builder();
}
public static TypeAdapter<Recipe> typeAdapter(Gson gson) {
return new AutoValue_Recipe.GsonTypeAdapter(gson);
}
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder id(int id);
public abstract Builder name(String name);
public abstract Builder ingredients(List<Ingredients> ingredients);
public abstract Builder steps(List<Step> steps);
public abstract Builder servings(int servings);
public abstract Builder image(String image);
public abstract Recipe build();
}
}
現在,我嘗試轉換上面的代碼以實現Parcelable接口,但是,現在我的代碼無法正常工作。 請幫助我將此類轉換為實現Parcelable接口。
@AutoValue
public abstract class Recipe implements Parcelable {
public static final String ID = "id";
public static final String NAME = "name";
public static final String INGREDIENTS = "ingredients";
public static final String STEPS = "steps";
public static final String SERVINGS = "servings";
public static final String IMAGE = "image";
private int id;
private String name;
private List<Ingredients> ingredients;
private List<Step> steps;
private int servings;
private String image;
public abstract int id();
public abstract String name();
public abstract List<Ingredients> ingredients();
public abstract List<Step> steps();
public abstract int servings();
public abstract String image();
public static Recipe.Builder builder() {
return new AutoValue_Recipe.Builder();
}
public static TypeAdapter<Recipe> typeAdapter(Gson gson) {
return new AutoValue_Recipe.GsonTypeAdapter(gson);
}
public static final class Builder {
private final ContentValues values = new ContentValues();
List<Ingredients> ingredient;
List<Step> step;
public Recipe.Builder id(int id) {
values.put(ID, id);
return this;
}
public Builder name(String name) {
values.put(NAME, name);
return this;
}
public Builder ingredients(List<Ingredients> ingredients) {
*//*for(int i=0; i<ingredients.size(); i++) {
values.put(INGREDIENTS, ingredients.get(i).ingredient());
}*//*
this.ingredient = ingredients;
return this;
}
public Builder steps(List<Step> steps) {
*//*for(int i=0; i<steps.size(); i++) {
values.put(STEPS, steps.get(i));
}*//*
this.step = steps;
return this;
}
public Builder servings(int servings) {
values.put(SERVINGS, servings);
return this;
}
public Builder image(String image) {
values.put(IMAGE, image);
return this;
}
public Recipe build() {
Recipe recipe = null;
recipe.id = (int) values.get(ID);
recipe.name = (String) values.get(NAME);
recipe.ingredients = ingredient;
recipe.steps = step;
recipe.servings = (int) values.get(SERVINGS);
recipe.image = (String) values.get(IMAGE);
return recipe;
}
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(id);
dest.writeString(name);
dest.writeList(ingredients);
dest.writeList(steps);
dest.writeInt(servings);
dest.writeString(image);
}
}
編輯:我將使用修改后的類來處理設備旋轉,以將回收器視圖的滾動狀態保存在片段中。 我的onSaveInstanceState()方法看起來像這樣,
private static final String BUNDLE_RECYCLER_LAYOUT = "BUNDLE_RECYCLER_LAYOUT";
ArrayList<Recipe> mRecipeList = new ArrayList<>(0);
@Override
public void onSaveInstanceState(Bundle bundle) {
super.onSaveInstanceState(bundle);
bundle.putParcelable(BUNDLE_RECYCLER_LAYOUT,
mRecipeListRecyclerView.getLayoutManager().onSaveInstanceState());
bundle.putParcelableArrayList(BUNDLE_RECYCLER_RECIPE_DATA, mRecipeList);
}
putParcelable內部的第二個參數是Parcelable類型。
我的onCreateView()方法如下所示:
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup
container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_recipe_list, container, false);
unbinder = ButterKnife.bind(this, view);
if(savedInstanceState != null) {
Parcelable savedRecyclerViewState = savedInstanceState.getParcelable(BUNDLE_RECYCLER_LAYOUT);
mRecipeListRecyclerView.getLayoutManager().onRestoreInstanceState(savedRecyclerViewState);
mRecipeList = savedInstanceState.getParcelableArrayList(BUNDLE_RECYCLER_RECIPE_DATA);
mRecipeListAdapter.refreshRecipes(mRecipeList);
} else {
mRecipeList = getArguments().getParcelableArrayList(BUNDLE_RECYCLER_RECIPE_DATA);
}
mRecipeListAdapter = new RecipeListAdapter(getContext(), mRecipeList, recipeId
-> mRecipeListPresenter.loadRecipeDetails(recipeId));
mRecipeListAdapter.setHasStableIds(true);
gridLayoutManager = new GridLayoutManager(getContext(), mGridColumnCount);
mRecipeListRecyclerView.setLayoutManager(gridLayoutManager);
mRecipeListRecyclerView.setHasFixedSize(true);
mRecipeListRecyclerView.setAdapter(mRecipeListAdapter);
return view;
}
任何幫助都將非常有用,因為我在轉換類以實現Parcelable接口時遇到困難。
mRecipeListRecyclerView.getLayoutManager().onRestoreInstanceState(savedRecyclerViewState);
您不需要調用onRestoreInstanceState()
。 這已被Android系統自動調用。 此外,您不需要自己保存和還原ArrayList
。 RecyclerView
已經為您處理了這些詳細信息。
至於保存滾動位置,您應該做更多的研究。 例如,我發現ListView通過快速搜索跳到屏幕方向更改的頂部 。 該鏈接有一個明確的示例,該示例演示了如何執行所需的操作。
這個答案是關於ScrollView
但是示例代碼與您所需要的非常相似。
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