不能将MenuItem转换为com.android.gms.ads.NativeExpressAdView

Question

我有一个应用程序，使用一个回收视图与代码集成从谷歌的样本回收与本地快速广告github。当我启动应用程序时，广告会在顶部加载，但当我开始滚动时，我的适配器中就会出现异常。

com.google.android.gms.ads.NativeExpressAdView :不能将java.lang.ClassCastException转换为dstudios.project.Utilities.MenuItem

适配器中的代码如下所示：

case NATIVE_EXPRESS_AD_VIEW_TYPE:

        default:
            NativeExpressAdViewHolder nativeExpressHolder =
                    (NativeExpressAdViewHolder) holder;
            NativeExpressAdView adView = (NativeExpressAdView) mData.get(position);
            ViewGroup adCardView = (ViewGroup) nativeExpressHolder.itemView;
            // The NativeExpressAdViewHolder recycled by the RecyclerView may be a different
            // instance than the one used previously for this position. Clear the
            // NativeExpressAdViewHolder of any subviews in case it has a different
            // AdView associated with it, and make sure the AdView for this position doesn't
            // already have a parent of a different recycled NativeExpressAdViewHolder.
            if (adCardView.getChildCount() > 0) {
                adCardView.removeAllViews();
            }
            if (adView.getParent() != null) {
                ((ViewGroup) adView.getParent()).removeView(adView);
            }

            // Add the Native Express ad to the native express ad view.
            adCardView.addView(adView);

在这一行中发生了异常：

                NativeExpressAdView adView = (NativeExpressAdView) mData.get(position);

正在使用的列表在顶部的适配器中声明：

private final List<Object> mData;

我的菜单类是这样的：

public class MenuItem {
    public String Name;
    public String UCPC;
    public String QR;
    public String URL;
    public String Image;
    public String Company;
    public String Reviews;
    public String CreatedAt;
    public String CountryOrigin;
    public String UpdatedAt;
    public String Lineage;
    public String Genetics;
    public String Countries;


    public MenuItem(String name, String UCPC, String Genetics, String URL,
                    String image, String updatedAt, String QR) {
        this.Name = name;
        this.UCPC = UCPC;
        this.Genetics = Genetics;
        this.URL = URL;
        this.Image = image;
        this.UpdatedAt = updatedAt;
        this.QR = QR;
    }

    public String getName() {
        return Name;
    }

    public String getUCPC() {
        return UCPC;
    }

    public String getGenetics() {
        return Genetics;
    }

    public String getURL() {
        return URL;
    }

    public String getImage() {
        return Image;
    }
    public String updatedAt() {
        return UpdatedAt;
    }
    public String QR() {
        return QR;
    }
}

我不知道它为什么要抛出例外，任何帮助都将是非常感谢的！

Answer 1

当您试图将一个对象强制转换到一个不是它的实例的类时，就会发生ClassCastExceptions。

在您的示例中，mData.get(position)返回一个类型为MenuItem的对象。您正在尝试将其转换为NativeExpressAdView --因此，会发生以下错误：

com.google.android.gms.ads.NativeExpressAdView :不能将java.lang.ClassCastException转换为dstudios.project.Utilities.MenuItem

所以，我不知道您是如何构造数据的，但是要解决这个问题，所需要做的就是确保mData.get(position)返回一个类型为NativeExpressAdView的对象。