Question

我正在制作一个android移动应用。我试图在MainActivity中保存数据。但是有太多数据，我发现将其保留在MainActivity中是不合适的。因此，我决定创建一个名为Data的Java类来保留代码。但是以某种方式，我无法调用Data类。

Data.java

package com.example.lenovo.pointofinterest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

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

public class Data extends AppCompatActivity {

    //a list to store all the places
    List<Places> placesList;

    //the recyclerview
    RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //getting the recyclerview from xml
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

        //initializing the placesList
        placesList= new ArrayList<>();


        //adding some items to our list
        placesList.add(
                new Places(
                        1,
                        "Adventure Zone Theme Park",
                        "13.3 inch, Silver, 1.35 kg",
                        "Amusement Park",
                        "10.00am - 7.00pm (Daily)",
                        R.drawable.adventure_zone_theme_park));

        placesList.add(
                new Places(
                        1,
                        "Escape Penang Theme Park",
                        "14 inch, Gray, 1.659 kg",
                        "Amusement Park",
                        "10.00am - 6.00pm (Tue - Sun)",
                        R.drawable.escape_penang_theme_park));

        placesList.add(
                new Places(
                        1,
                        "Countryside Stables Penang",
                        "13.3 inch, Silver, 1.35 kg",
                        "Animal Lover",
                        "2.00pm - 7.00pm (Daily)",
                        R.drawable.countryside_stables_penang));

        //creating recyclerview adapter
        PlacesAdapter adapter = new PlacesAdapter (this, placesList);

        //setting adapter to recyclerview
        recyclerView.setAdapter(adapter);
    }
}

MainActivity.java

package com.example.lenovo.pointofinterest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

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


public class MainActivity{


}

我尝试通过遵循此处的提示（可能是onCreate引起的提示）来编辑代码，但是我仍然无法修复它。请帮忙。谢谢。

Answer 1

我觉得你打算这样做

public class Data {

    //a list to store all the places
    public static List<Places> placesList = Arrays.asList(new Places(), new Places());

}

就是这样。然后在MainActivity（仍然需要扩展一些Activity类）中，您可以引用Data.placesList放入适配器

PlacesAdapter adapter = new PlacesAdapter(MainActivity.this, Data.placesList);

如果需要，可以将适配器放入数据类，但是应该使用RecyclerView并从MainActivity中找到它。

Answer 2

首先，您的MainActivity需要扩展AppComapActivity

第二，您需要在MainActivity中进行创建。

@Override
protected void onCreate(Bundle savedInstanceState) {
   Intent intent = new Intent(getApplicationContext(), YourClass.class);
   startActivity(intent);
}

然后，您可以在主活动中调用您的课程。

如何将整个班级称为“主要活动”？

2 个答案: