如何修复 recycleview 项目中的“尝试调用虚拟方法”错误？

Question

我编写了一个代码，其目标是将数组列表项设置为回收视图。但是当我运行该项目时，应用程序将崩溃。

d.

我检查依赖关系。他们没事。我检查了代码，我认为它们没有任何问题。

//主活动类

public class MainActivity extends AppCompatActivity {

RecyclerView rcl_cities;

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    initViews();

    Log.e("ApplicationSays:","LayoutManager set");

}

private void initViews(){

    rcl_cities = findViewById(R.id.rcl_cities);

    rcl_cities.setLayoutManager(new LinearLayoutManager(this,RecyclerView.VERTICAL,false));

    CityAdapter cityAdapter = new CityAdapter(this,getCities());

    rcl_cities.setAdapter(cityAdapter);

}

private ArrayList<City> getCities()

{

    ArrayList<City> cities = new ArrayList<>();

    cities.add(new City(1, "mashhad"));

    cities.add(new City(2, "Tehran"));

    cities.add(new City(3, "Gorgan"));

    cities.add(new City(4, "Shiraz"));

    cities.add(new City(5, "Rasht"));

    return cities;

}

}

Answer 1

首先，将您的更改view为xmlView<View&nbsp; &nbsp; android:layout_width="match_parent"&nbsp; &nbsp; android:layout_height="3dp"&nbsp; &nbsp; android:background="@android:color/holo_red_dark" />其次，你没有按照你的onBindViewHolder方法做正确的事情City city = cities.get(position);在尝试向 City 传递值之前，应先声明并初始化 City 的实例。City city;//....city = new City//...city.setId(cities.get(position));这样您就可以再次测试您的代码。