Question

如何使用回收视图适配器将多个数据集作为对象加载？我尝试使用示例，但出现了与演员表相关的错误。有人可以帮忙吗？这是我从中填充数据并调用适配器的活动的代码-

package com.example.aniketmondal.aniskitchen;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
public class OrderPage extends AppCompatActivity {

    private  FoodAdapter adapter;
    private Query query;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_order_page);
        setUpRecyclerView();
    }
    private void setUpRecyclerView() {
        query = FirebaseDatabase.getInstance().getReference().child("/Food/Mughlai");
        FirebaseRecyclerOptions<Food> options = new FirebaseRecyclerOptions.Builder<Food>().setQuery(query, Food.class).build();
        adapter = new FoodAdapter(options);
        RecyclerView rcview = findViewById(R.id.post_rv);
        rcview.setHasFixedSize(true);
        rcview.setLayoutManager(new LinearLayoutManager(this));
        rcview.setAdapter(adapter);
    }
    @Override
    protected void onStart() {
        super.onStart();
        adapter.startListening();
    }
    @Override
    protected void onStop() {
        super.onStop();
        adapter.stopListening();
    }
}

Answer 1

您可以尝试在RecyclerView方法上设置onCreate。但是，最重要的是，您的适配器正在调用startListening()方法，您没有从父类中重写该方法。因此，您可以将setUpRecyclerView()重命名为startListening。如果您在此处设置RecyclerView，则无需从onCreate调用它。看起来像这样...

package com.example.aniketmondal.aniskitchen;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;

public class OrderPage extends AppCompatActivity {

    private  FoodAdapter adapter;
    private Query query;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_order_page);
        RecyclerView rcview = findViewById(R.id.post_rv);
        rcview.setHasFixedSize(true);
        rcview.setLayoutManager(new LinearLayoutManager(this));
    }
    @Override
    private void startListening() {
        query = FirebaseDatabase.getInstance().getReference().child("/Food/Mughlai");
        FirebaseRecyclerOptions<Food> options = new FirebaseRecyclerOptions.Builder<Food>().setQuery(query, Food.class).build();
        adapter = new FoodAdapter(options);          
        rcview.setAdapter(adapter);
    }
    @Override
    protected void onStart() {
        super.onStart();
        adapter.startListening();
    }
    @Override
    protected void onStop() {
        super.onStop();
        adapter.stopListening();
    }
}

Answer 2

如果您已在onStart中添加了侦听器，则必须在onStop中将其删除。

如果您已在onResume中添加了侦听器，则必须在onPause中将其删除。

如果您已在onCreate中添加了侦听器，则必须在onDestroy中将其删除。但是请记住，并非总是调用onDestroy。

RecyclerviewAdapter代码在android

2 个答案: