Question

我正尝试将对象列表从活动发送到片段，其中我的对象和对象列表模型扩展了Parcable：

（CurrencyModel）

public class CurrencyModel implements Parcelable
{

@SerializedName("name")
@Expose
private String name;
@SerializedName("slug")
@Expose
private String slug;
@SerializedName("type")
@Expose
private String type;
@SerializedName("unit")
@Expose
private String unit;
@SerializedName("fee_percent")
@Expose
private String feePercent;
@SerializedName("price_usd")
@Expose
private String priceUsd;
@SerializedName("change_24")
@Expose
private String change24;
@SerializedName("min")
@Expose
private String min;
@SerializedName("max")
@Expose
private String max;
@SerializedName("stock")
@Expose
private String stock;
@SerializedName("wallet")
@Expose
private String wallet;
@SerializedName("updated_at")
@Expose
private String updatedAt;
@SerializedName("icon")
@Expose
private String icon;
public final static Parcelable.Creator<CurrencyModel> CREATOR = new Creator<CurrencyModel>() {


    @SuppressWarnings({
            "unchecked"
    })
    public CurrencyModel createFromParcel(Parcel in) {
        return new CurrencyModel(in);
    }

    public CurrencyModel[] newArray(int size) {
        return (new CurrencyModel[size]);
    }

}
        ;

protected CurrencyModel(Parcel in) {
    this.name = ((String) in.readValue((String.class.getClassLoader())));
    this.slug = ((String) in.readValue((String.class.getClassLoader())));
    this.type = ((String) in.readValue((String.class.getClassLoader())));
    this.unit = ((String) in.readValue((String.class.getClassLoader())));
    this.feePercent = ((String) in.readValue((String.class.getClassLoader())));
    this.priceUsd = ((String) in.readValue((String.class.getClassLoader())));
    this.change24 = ((String) in.readValue((String.class.getClassLoader())));
    this.min = ((String) in.readValue((String.class.getClassLoader())));
    this.max = ((String) in.readValue((String.class.getClassLoader())));
    this.stock = ((String) in.readValue((String.class.getClassLoader())));
    this.wallet = ((String) in.readValue((String.class.getClassLoader())));
    this.updatedAt = ((String) in.readValue((String.class.getClassLoader())));
    this.icon = ((String) in.readValue((String.class.getClassLoader())));
}

public CurrencyModel() {
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getSlug() {
    return slug;
}

public void setSlug(String slug) {
    this.slug = slug;
}

public String getType() {
    return type;
}

public void setType(String type) {
    this.type = type;
}

public String getUnit() {
    return unit;
}

public void setUnit(String unit) {
    this.unit = unit;
}

public String getFeePercent() {
    return feePercent;
}

public void setFeePercent(String feePercent) {
    this.feePercent = feePercent;
}

public String getPriceUsd() {
    return priceUsd;
}

public void setPriceUsd(String priceUsd) {
    this.priceUsd = priceUsd;
}

public String getChange24() {
    return change24;
}

public void setChange24(String change24) {
    this.change24 = change24;
}

public String getMin() {
    return min;
}

public void setMin(String min) {
    this.min = min;
}

public String getMax() {
    return max;
}

public void setMax(String max) {
    this.max = max;
}

public String getStock() {
    return stock;
}

public void setStock(String stock) {
    this.stock = stock;
}

public String getWallet() {
    return wallet;
}

public void setWallet(String wallet) {
    this.wallet = wallet;
}

public String getUpdatedAt() {
    return updatedAt;
}

public void setUpdatedAt(String updatedAt) {
    this.updatedAt = updatedAt;
}

public String getIcon() {
    return icon;
}

public void setIcon(String icon) {
    this.icon = icon;
}

public void writeToParcel(Parcel dest, int flags) {
    dest.writeValue(name);
    dest.writeValue(slug);
    dest.writeValue(type);
    dest.writeValue(unit);
    dest.writeValue(feePercent);
    dest.writeValue(priceUsd);
    dest.writeValue(change24);
    dest.writeValue(min);
    dest.writeValue(max);
    dest.writeValue(stock);
    dest.writeValue(wallet);
    dest.writeValue(updatedAt);
    dest.writeValue(icon);
}

public int describeContents() {
    return 0;
}

}

和GetCurrenciesModel：

public class GetCurrenciesModel implements Parcelable
{

@SerializedName("status")
@Expose
private Boolean status;
@SerializedName("message")
@Expose
private String message;
@SerializedName("currencies")
@Expose
private List<CurrencyModel> currencies = null;
public final static Parcelable.Creator<GetCurrenciesModel> CREATOR = new     Creator<GetCurrenciesModel>() {


    @SuppressWarnings({
            "unchecked"
    })
    public GetCurrenciesModel createFromParcel(Parcel in) {
        return new GetCurrenciesModel(in);
    }

    public GetCurrenciesModel[] newArray(int size) {
        return (new GetCurrenciesModel[size]);
    }

}
        ;

protected GetCurrenciesModel(Parcel in) {
    this.status = ((Boolean) in.readValue((Boolean.class.getClassLoader())));
    this.message = ((String) in.readValue((String.class.getClassLoader())));
    in.readList(this.currencies, (CurrencyModel.class.getClassLoader()));
}

public GetCurrenciesModel() {
}

public Boolean getStatus() {
    return status;
}

public void setStatus(Boolean status) {
    this.status = status;
}

public String getMessage() {
    return message;
}

public void setMessage(String message) {
    this.message = message;
}

public List<CurrencyModel> getCurrencies() {
    return currencies;
}

public void setCurrencies(List<CurrencyModel> currencies) {
    this.currencies = currencies;
}

public void writeToParcel(Parcel dest, int flags) {
    dest.writeValue(status);
    dest.writeValue(message);
    dest.writeList(currencies);
}

public int describeContents() {
    return 0;
}

}

这是我添加要捆绑的货币列表以便将其发送到片段的方法：

                    Bundle bundle = new Bundle();
                    bundle.putParcelableArrayList("Currencies", (ArrayList<? extends Parcelable>)currencies);
                    setData();
                    Fragment fragment = new FeesFragment();
                    fragment.setArguments(bundle);

我确定不会为null的货币，因为我烘烤了它的值。但是，当我尝试从这样的片段中检索该信息时：

            currencies = getArguments().getParcelableArrayList("Currencies");

我将得到NullPointerException Erro，因为货币为null。请帮我解决这个问题。

更新：

错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.ArrayList android.os.Bundle.getParcelableArrayList(java.lang.String)' on a null object reference
    at com.x.x.Fragments.FeesFragment.onCreateView(FeesFragment.java:56)

注意：

FeesFragment也被另一个地方调用。我正在使用tabView

        @Override
    public Fragment getItem(int position) {

        switch (position){

            case 0 :
                // Another Fragment
            case 1 :
                return new FeesFragment();
        }

        return null;
    }

Answer 1

您的片段没有设置参数。

return new FeesFragment();

这不会使用args软件包设置片段，因此getArguments()返回null。使用设置参数束的代码来实例化片段。

Answer 2

可能是由于敏感性问题；您的@SerializedName（“ currencies”）以'c'开头，并且您正在尝试使用“ Currencies”从分发包中获取Parcelable ArrayList。

获取NullPointerExecption，以获取Android片段中的对象的可分析列表

2 个答案: