帶子類的ParseQueryAdapter，android爲什麼我無法從Parse獲取數據？

Question

我正在使用Parse.com構建一個Android應用程序，並且我正在最困難的時候弄清楚什麼不起作用。爲什麼我沒有看到我的分類名稱列表？

我沒有收到任何錯誤，但是當我的活動運行時沒有看到我的數據。我有這兩個解析類，一個配方可能是多個類別的一部分。

@ParseClassName("Category") 
public class Category extends ParseObject { 

public Category() { 
} 

public String getName() { 
    return getString("name"); 
} 

public void setName(String name) { 
    put("name", name); 
} 


} 

@ParseClassName("Recipe") 
public class Recipe extends ParseObject{ 

public Recipe() { 
} 

public String getName() { 
    return getString("name"); 
} 
public void setName(String name) { 
    put("name", name); 
} 

public Number getTotalMeatAndFat(){ 
    return getNumber("totalMeatAndFat"); 
} 
public void setTotalMeatAndFat(Number totalMeatAndFat){put("totalMeatAndFat", totalMeatAndFat);} 

public String getUnit(){ return getString("unit");} 
public void setUnit(String unit) { 
    put("unit", unit); 
} 
} 

我已經創建並通過調用函數CreateData看起來像這樣保存我的解析數據：

public void CreateData() { 
     // create the categories 
    Category fCat = new Category(); 
    fCat.put("name", "Fresh Sausages"); 
    fCat.saveInBackground(); 
    Category erCat = new Category(); 
    erCat.put("name", "Fermented Sausages"); 
    erCat.saveInBackground(); 

    // create the base recipes 
    Recipe rec = new Recipe(); 
    rec.setName("Sweet Italian"); 
    rec.setTotalMeatAndFat(1000); 
    rec.setUnit("g"); 

    Recipe rec1 = new Recipe(); 
    rec1.setName("Hot Italian"); 
    rec1.setTotalMeatAndFat(1000); 
    rec1.setUnit("g"); 

    Recipe rec2 = new Recipe(); 
    rec2.setName("Chorizo Cantimpalos Style"); 
    rec2.setTotalMeatAndFat(1000); 
    rec2.setUnit("g"); 

    // assign recipes to categories 
    ParseRelation<Category> relationRecCat = rec.getRelation("categories"); 
    relationRecCat.add(fCat); 
    rec.saveInBackground(); 

    ParseRelation<Category> relationRec1Cat = rec1.getRelation("categories"); 
    relationRec1Cat.add(fCat); 
    rec1.saveInBackground(); 

    ParseRelation<Category> relRec2Cat = rec2.getRelation("categories"); 
    relRec2Cat.add(erCat); 
    rec2.saveInBackground(); 
} 

這裏是我的category_list.xml文件的佈局：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:orientation="vertical" android:layout_width="match_parent" 
android:layout_height="match_parent"> 

<TextView 
    android:id="@+id/title" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" /> 

<ListView 
    android:id="@+id/listview" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"></ListView> 

</LinearLayout> 

最後，這裏是我的CategoryListActivity onCreate方法。再次，我在佈局中放置了一個TextView，以便我可以看到佈局是否正在使用。

import android.app.Activity; 
import android.os.Bundle; 
import android.widget.ListView; 
import android.widget.TextView; 
import android.widget.Toast; 

import com.parse.ParseQueryAdapter; 
import com.parse.ParseUser; 


public class CategoryListActivity extends Activity { 
private TextView titleTextView; 
private ListView listView; 

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.category_list); 

    listView = (ListView) findViewById(R.id.listview); 

    ParseQueryAdapter<Category> adapter; 
    adapter = new ParseQueryAdapter<Category>(this , Category.class); 
    adapter.setTextKey("name"); 
    listView.setAdapter(adapter); 

    // this is just to see if we are getting anywhere at all. 
    titleTextView = (TextView) findViewById(R.id.title); 
    titleTextView.setText(R.string.hello_world); 
} 

@Override 
protected void onStart() { 
    super.onStart(); 
    // Set up the profile page based on the current user. 
    ParseUser user = ParseUser.getCurrentUser(); 
    showProfile(user); 
} 

private void showProfile(ParseUser user) { 
    if (user != null) { 
     String fullName = user.getString("name"); 
     if (fullName != null) { 
      Toast.makeText(getApplicationContext(), "You are logged in as" + fullName, Toast.LENGTH_SHORT).show(); 
     } 

    } 
} 

Answer 1

我結束了使用ListActivity，並創建一個自定義適配器。

public class CategoryListActivity extends ListActivity { 

int listCount = -1; 
private CategoryViewListViewAdapter adapter; 

public static final String TAG = CategoryListActivity.class.getSimpleName(); 

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    getListView().setClickable(true); 

    CategoryViewListViewAdapter adapter = new CategoryViewListViewAdapter(this); 

    adapter.addOnQueryLoadListener(new ParseQueryAdapter.OnQueryLoadListener<Category>() { 
     @Override 
     public void onLoading() { 
      //Toast.makeText(getApplicationContext(), "Loading...", Toast.LENGTH_LONG).show(); 
      Log.d(TAG, "Loading....."); 
     } 

     @Override 
     public void onLoaded(List<Category> list, Exception e) { 
      Log.d(TAG, "Loading complete."); 
      Log.d(TAG, "List contains "+ list.size() + " items"); 
      // this is just to see if we are getting anywhere at all. 


     } 
    }); 

    setListAdapter(adapter); 


} 

@Override 
protected void onStart() { 
    super.onStart(); 
    // Set up the profile page based on the current user. 
    ParseUser user = ParseUser.getCurrentUser(); 
    showProfile(user); 
} 

private void showProfile(ParseUser user) { 
    if (user != null) { 
     String fullName = user.getString("name"); 
     if (fullName != null) { 
      Toast.makeText(getApplicationContext(), "You are logged in as " + fullName, Toast.LENGTH_SHORT).show(); 
     } 

    } 
} 

// OnListItemClick event 
@Override 
protected void onListItemClick(ListView l, View v, int position, long id) { 
    // Display item in toast. 
    super.onListItemClick(l, v, position, id); 

    Category cat = (Category) l.getAdapter().getItem(position); 
    String objId = cat.getObjectId().toString(); 
    Log.d(TAG, "Category name = "+ cat.getName()); 
    Log.d(TAG, "Category object id = "+ objId); 
    // now we have the category, we want to go get the list of Recipes in that category. 
    Intent intent = new Intent(this, RecipeListActivity.class); 
    EventBus.getDefault().postSticky(cat); 
    startActivity(intent); 

} 



class CategoryViewListViewAdapter extends ParseQueryAdapter<Category> { 

public CategoryViewListViewAdapter(Context context) { 
    super(context, new ParseQueryAdapter.QueryFactory<Category>() { 
     public ParseQuery<Category> create() { 
      ParseQuery<Category> query = ParseQuery.getQuery(Category.class); 
      //query.include("User"); 
      query.whereExists("name"); 
      query.orderByAscending("name"); 
      return query; 
     } 
    }); 

} 
@Override 
public View getItemView(Category category, View v, ViewGroup parent) { 
    if(v == null) { 
     v = View.inflate(getContext(), R.layout.category_list_item, null); 
    } 

    super.getItemView(category, v, parent); 

    final TextView catTextView = (TextView) v.findViewById(R.id.category_name); 
    catTextView.setText(category.getName()); 
    return v; 
} 

}