在Android上，我怎么能建立从境界列表的领域适配器？ [英] On Android, how can I build a Realm Adapter from a Realm List?

问题描述

我在Android上使用境界写的食谱应用程序。我有型成分在每个配方对象RealmList。对象创建code是工作的罚款。

I'm writing a recipe app on Android using Realm. I have a RealmList of type Ingredient in each Recipe object. The object creation code is working fine.

现在我正在写的code为显示单个配方的片段。我能创造一个领域适配器的所有配方标题列表，因为我使用内置的查询，像这样的列表：

Now I'm writing the code for the Fragment that displays a single recipe. I was able to create a Realm Adapter for the all recipe titles list, since I built that list using a query like so:

public class RecipeTitleAdapter extends RealmBaseAdapter<RecipeTitle> implements ListAdapter {

    public RecipeTitleAdapter(Context context, int resId,
                 RealmResults<RecipeTitle> realmResults,
                 boolean automaticUpdate) { 
    ...

recipeTitles = RecipeTitle.returnAllRecipeTitles(realm);
final RecipeTitleAdapter adapter = new RecipeTitleAdapter(RecipeParserApplication.appContext, R.id.recipe_list_view, recipeTitles, true);

但现在，我在看的成分为单一的配方，我有成分的RealmList而不是RealmResults对象。我的成分适配器类具有相同类型构造为配方标题适配器，所以我想知道如何（或者即使）我可以把它的工作开始了RealmList。

But now that I'm looking at the ingredients for a single recipe, I have a RealmList of Ingredients and not a RealmResults object. My ingredient adapter class has the same type of constructor as the recipe titles adapter, so I want to know how (or even if) I can make it work starting with a RealmList.

public class IngredientAdapter extends RealmBaseAdapter<Ingredient> implements ListAdapter {

private static class ViewHolder {
    TextView quantity;
    TextView unitOfMeasure;
    TextView ingredientItemName;
    TextView processingInstructions;
}

public IngredientAdapter(Context context, int resId,
                          RealmResults<Ingredient> realmResults,
                          boolean automaticUpdate) {
....

final IngredientAdapter adapter = new IngredientAdapter(RecipeParserApplication.appContext, R.id.ingredientListView, recipe.getIngredients(), true);

public RealmList<Ingredient> getIngredients() {
    return ingredients;
}

由于recipe.getIngredients返回RealmList，其中IngredientAdapter分配收益编译错误行：

Since recipe.getIngredients returns a RealmList, the line where the IngredientAdapter is assigned returns a compile error:

错误：（63，43）误差：构造IngredientAdapter类IngredientAdapter不能被应用到给定的类型;
要求：方面，诚信，RealmResults，布尔
发现：上下文，INT，RealmList，布尔
原因：实际参数RealmList无法通过方法调用转换转换为RealmResults

Error:(63, 43) error: constructor IngredientAdapter in class IngredientAdapter cannot be applied to given types; required: Context,int,RealmResults,boolean found: Context,int,RealmList,boolean reason: actual argument RealmList cannot be converted to RealmResults by method invocation conversion

推荐答案

一个RealmList如同一个正常的数组，因此，如果您不能进行查询匹配要显示，你可以使用任何正常的适配器像什么例如一个ArrayAdapter。使用RealmBaseAdapter的唯一优点是它autorefreshes，但是这是相当容易完成自己：

A RealmList behaves like an normal array, so if you cannot make a query that matches what you want to display, you can just use any of the normal adapters like e.g. a ArrayAdapter. The only advantage of using a RealmBaseAdapter is that it autorefreshes, but that is fairly easy to accomplish yourself:

// Pseudo code
ArrayAdapter adapter;
RealmChangeListener listener = new RealmChangeListener() {
  public void onChange() {
    if (adapter != null) {
      adapter.notifyDataSetChanged();
    }
  }
}

protected void onCreate(Bundle savedInstanceState) {
  // ... 
  realm.addChangeListener(listener);
  RealmList data = getRealmListData();
  adapter = new ArrayAdapter(data);
  listView.setAdapter(adapter);
}

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