带有parce.com的Android应用。 跳过布局

Question

这是我的代码。问题是，当我改变方向时，出现了这样的一行：没有连接适配器； 跳过布局。标有红色。但是在经过几毫秒的布局后。所以我想知道是否可以，或者我应该以某种方式更改代码？

package by.test.roma.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import com.parse.FindCallback;
import com.parse.GetCallback;
import com.parse.Parse;
import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.ParseQuery;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    RecyclerView recyclerView;
    LinearLayoutManager manager;
    List<Recipe> recipes;
    static int count = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        recipes = new ArrayList<Recipe>();

        // Enable Local Datastore.
        if(count == 0) {
            Parse.enableLocalDatastore(this);
            Parse.initialize(this, "id", "key");
            count++;
        }
        ParseQuery<ParseObject> query = ParseQuery.getQuery("Recipes");
        query.findInBackground(new FindCallback<ParseObject>() {
            public void done(List<ParseObject> recipesList, ParseException e) {
                if (e == null) {
                    Log.d("score", "Retrieved " + recipesList.size() + " recipes");
                    for(ParseObject obj :recipesList) {
                       initializeData(obj);
                }
                } else {
                    Log.d("score", "Error: " + e.getMessage());
                }
                initializeAdapter();
            }
        });

        setContentView(R.layout.activity_main);
        recyclerView = (RecyclerView)findViewById(R.id.recyclerView);
        manager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(manager);

        //initializeData();



    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
    private void initializeAdapter(){
        RVAdapter adapter = new RVAdapter(recipes);
        recyclerView.setAdapter(adapter);
    }
    private void initializeData(ParseObject obj){
        recipes.add(new Recipe(obj.getString("Description"), obj.getString("shortDescription"), obj.getString("Name"), R.drawable.share));
        Log.d("score", Integer.toString(recipes.size()));
    }
}



My log : 
08-28 14:04:28.913  14256-14256/by.test.roma.myapplication D/﹕ mali: REVISION=Linux-r2p4-02rel0 BUILD_DATE=Fri May  4 10:32:42 KST 2012
08-28 14:04:28.948  14256-14256/by.test.roma.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0
08-28 14:04:28.948  14256-14256/by.test.roma.myapplication E/RecyclerView﹕ No adapter attached; skipping layout
08-28 14:04:28.983  14256-14256/by.test.roma.myapplication E/RecyclerView﹕ No adapter attached; skipping layout
08-28 14:04:29.058  14256-14256/by.test.roma.myapplication D/CLIPBOARD﹕ Hide Clipboard dialog at Starting input: finished by someone else... !
08-28 14:04:29.573  14256-14256/by.test.roma.myapplication D/score﹕ Retrieved 2 recipes
08-28 14:04:29.573  14256-14256/by.test.roma.myapplication D/score﹕ 1
08-28 14:04:29.573  14256-14256/by.test.roma.myapplication D/score﹕ 2
08-28 14:04:29.603  14256-14257/by.test.roma.myapplication D/dalvikvm﹕ GC_CONCURRENT freed 299K, 8% free 13141K/14215K, paused 2ms+2ms
08-28 14:04:29.618  14256-14256/by.test.roma.myapplication D/dalvikvm﹕ GC_FOR_ALLOC freed 4K, 8% free 13239K/14343K, paused 13ms
08-28 14:04:29.618  14256-14256/by.test.roma.myapplication I/dalvikvm-heap﹕ Grow heap (frag case) to 14.041MB for 417616-byte allocation
08-28 14:04:29.633  14256-14256/by.test.roma.myapplication D/dalvikvm﹕ GC_FOR_ALLOC freed <1K, 8% free 13646K/14791K, paused 13ms
08-28 14:04:43.178  14256-14256/by.test.roma.myapplication D/OpenGLRenderer﹕ Flushing caches (mode 0)
08-28 14:04:43.418  14256-14256/by.test.roma.myapplication E/RecyclerView﹕ No adapter attached; skipping layout
08-28 14:04:43.428  14256-14256/by.test.roma.myapplication E/RecyclerView﹕ No adapter attached; skipping layout
08-28 14:04:43.578  14256-14256/by.test.roma.myapplication D/score﹕ Retrieved 2 recipes
08-28 14:04:43.578  14256-14256/by.test.roma.myapplication D/score﹕ 1
08-28 14:04:43.578  14256-14256/by.test.roma.myapplication D/score﹕ 2
.
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Answer 1

您需要为绘制RecyclerView创建并设置适配器：

   setContentView(R.layout.activity_main);
    recyclerView = (RecyclerView)findViewById(R.id.recyclerView);
    manager = new LinearLayoutManager(getApplicationContext());
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(manager);
    // initialize your array and set an adapter even if its empty to avoid the 
    // skipping layout warning
    recipes = new ArrayList<>();
    RVAdapter adapter = new RVAdapter(recipes);
    recyclerView.setAdapter(adapter);

然后，一旦您获取并添加数据，即可：

    adapter.notifyDataSetChanged();

或更有效的：

    adapter.notifyItemInserted(positionOfItem);