Question

我想实现具有多种视图类型的RecyclerView。因此，我在适配器类中使用getItemViewType()方法：

    @Override
    public int getItemViewType(int position) {
        return mItems.get(position).getType();
    }

现在，出现以下错误：

不兼容的类型。必需的int。找到了字符串。

我知道：这是因为getType()方法返回的是String而不是int。

问题：如何返回整数？

Answer 1

您可以简单地为您的类型或局部变量创建一个枚举，并返回如下内容：

    companion object {
       private const val MY_MESSAGE = 0
       private const val OTHER_MESSAGE = 1
    }

    override fun getItemViewType(position: Int): Int {
        val item = mMessages[position]

        return if (item.isMine)
            MY_MESSAGE
        else
            OTHER_MESSAGE
    }

Answer 2

您必须将String转换为Integer值。

public class CustomAdapter {

    private static final int VIEW_TYPE_DEFAULT = 0;
    private static final int VIEW_TYPE_1 = 1;
    private static final int VIEW_TYPE_2 = 2;
    private static final int VIEW_TYPE_3 = 3;
    private static final int VIEW_TYPE_4 = 4;

    @Override
    public int getItemViewType(int position) {
        String typeString = mItems.get(position).getType();
        switch (typeString) {
            case "STRING1":
                return VIEW_TYPE_1;
            case "STRING2":
                return VIEW_TYPE_2;
            case "STRING3":
                return VIEW_TYPE_3;
            ....
            default:
                return VIEW_TYPE_DEFAULT;
        }
    }

    @Override
    public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
        switch (getItemViewType(position)) {
            case VIEW_TYPE_1;
                //bind viewtype 1
                break;
            case VIEW_TYPE_2;
                //bind viewtype 2
                break;
            case VIEW_TYPE_3;
                //bind viewtype 3
                break;
                ....
            default:
                // Bind default view
        }
    }
}

Answer 3

//Use Enums to separate the items type in the view.
enum class RecyclerViewDataType(val type: Int, val desc: String) {
     TYPE_HEADER(1, "Header"),
     TYPE_DATA(2, "Data"),
     TYPE_FOOTER(3, "Footer")
}

// Model to Define the Data
data class DataWithHeader(
    val viewType: RecyclerViewDataType,
    val headerLayoutResId: Int = R.layout.header,
    val data: Data = Data()
)

var items: List<DataWithHeader>

//viewType.type returns the required integer a/c to the item.
override fun getItemViewType(position: Int): Int {
    return items[position].viewType.type
}

Answer 4

要在recyclerview中处理视图类型，您的ArrayList应该具有某些唯一类型，或者必须具有getType（）函数

public abstract class Vehicle {
  protected int mType;
  protected String mName;

  abstract int getType();
  abstract int getName();

  public static class Types{
      int MotorCar  =  1;
      int Bike      =  2;
      int Truck     =  3;
  }

}

public class Ferrari extends Vehicle {

  public Ferrari{
      this.mType = Vehicle.Types.MotorCar;
      this.mName = "MotorCar";
  }

  @Override
  public int getType(){
      return mType;
  }

  @Override
  public String getName(){
      return mName;
  }
}

public class Yamaha extends Vehicle{

  public Yamaha{
      this.mType = Vehicle.Types.Bike;
      this.mName = "Bike";
  }

  @Override
  public int getType(){
      return mType;
  }

  @Override
  public String getName(){
      return mName;
  }
}

这样，当调用getItemViewType时，它将根据对象类型返回您想要的类型。

getItemViewType（）-如何返回int值

4 个答案: