我正在制作一个非盈利性慈善应用程序。尽管我检查了堆栈和Google中的许多问题，但我无法解决问题。
我有3节课：
-BaseCell实现Parcelable（基类）
-Needy扩展BaseCell
-包含所有类列表的UserBasket类扩展了BaseCell
问题
我在UserBasket类中使用Arraylist持有Needy类。当我将其发送到另一个活动时，如果我在UserBasket中添加1个项目，我会得到荒谬的结果（缺少或错误的字符），如果我添加了1个以上的项目，那么我会得到异常。
我需要将UserBasket类（有需要的物品清单）交付给付款活动，以便我可以计算出慈善总价并采取必要的行动。
public abstract class BaseCell implements Parcelable {
String imageUrl;
int percentageOfCollectedDonation;
String needyTitle;
String needyDescription;
protected String category;
protected int amountOfCollectedDonation=0;
protected int amountOfTargetDonation=0;
protected int amountOfDonater=0;
protected int drawableID;
protected String campaignCode;
protected int maxInstallmentNumber;
int price;
public String getCellType() {
return cellType;
}
protected String cellType ;
/**
* How many of this campaign purchased by user
* */
protected int userPurchaseAmount = 1;
protected BaseCell(String cellType)
{
this.cellType = cellType;
}
protected BaseCell(Parcel in)
{
drawableID = in.readInt();
price = in.readInt();
imageUrl = in.readString();
needyTitle = in.readString();
needyDescription = in.readString();
category = in.readString();
campaignCode = in.readString();
maxInstallmentNumber = in.readInt();
userPurchaseAmount = in.readInt();
}
public static final Parcelable.Creator<BaseCell> CREATOR = new Parcelable.Creator<BaseCell>() {
@Override
public BaseCell createFromParcel(Parcel in) {
String cellType = in.readString();
BaseCell baseCell = null;
if (cellType.equals("Needy"))
{
baseCell = (Needy)new Needy(in);
}else
if (cellType.equals("Qurban"))
{
baseCell = (Qurban)new Qurban(in);
}
return baseCell;
}
@Override
public BaseCell[] newArray(int size) {
return new BaseCell[size];
}
};
public void writeToParcel(Parcel out, int flags) {
out.writeString(getCellType());
}
public BaseCell(String imageUrl, int drawableID, String needyTitle, String needyDescription, int amountOfCollectedDonation, int amountOfTargetDonation, int amountOfDonater, String category,String campaignCode, int maxInstallmentNumber, int price)
{
this.imageUrl = imageUrl;
this.drawableID = drawableID;
this.needyTitle = needyTitle;
this.needyDescription = needyDescription;
this.amountOfCollectedDonation = amountOfCollectedDonation;
this.amountOfTargetDonation = amountOfTargetDonation;
this.amountOfDonater = amountOfDonater;
this.category = category;
this.campaignCode = campaignCode;
this.maxInstallmentNumber = maxInstallmentNumber;
this.price= price;
}
}
有需要的
public class Needy extends BaseCell {
protected Needy(Parcel in) {
super(in);
cellType ="Needy";
}
public static final Parcelable.Creator<Needy> CREATOR = new Parcelable.Creator<Needy>() {
@Override
public Needy createFromParcel(Parcel in) {
return new Needy(in);
}
@Override
public Needy[] newArray(int size) {
return new Needy[size];
}
};
public Needy(String imageUrl, int drawableID, String needyTitle, String needyDescription, int amountOfCollectedDonation, int amountOfTargetDonation, int amountOfDonater, String category, String campaignCode, int maxInstallmentNumber, int price) {
super(imageUrl, drawableID, needyTitle, needyDescription, amountOfCollectedDonation, amountOfTargetDonation, amountOfDonater, category, campaignCode, maxInstallmentNumber,price);
cellType = "Needy";
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(getCellType());
super.writeToParcel(dest,flags);
dest.writeInt(drawableID);
dest.writeInt(price);
dest.writeString(imageUrl);
dest.writeString(needyTitle);
dest.writeString(needyDescription);
dest.writeString(category);
dest.writeString(campaignCode);
dest.writeInt(maxInstallmentNumber);
dest.writeInt(userPurchaseAmount);
}
@Override
public void setUserPurchaseAmount(int userPurchaseAmount) {
super.setUserPurchaseAmount(userPurchaseAmount);
}
}
用户篮
public class UserBasket implements Parcelable{
List<BaseCell> userBasket;
/**
* holds all items to be purchased
* */
public UserBasket(List<BaseCell> userBasket) {
this.userBasket = userBasket;
}
public UserBasket() {
userBasket = new ArrayList<>();
}
protected UserBasket(Parcel in) {
super();
setUserBasket(new ArrayList<BaseCell>());
userBasket = in.createTypedArrayList(BaseCell.CREATOR);
//in.readTypedList(userBasket,BaseCell.CREATOR);
}
public static final Parcelable.Creator<UserBasket> CREATOR = new Parcelable.Creator<UserBasket>() {
@Override
public UserBasket createFromParcel(Parcel in) {
return new UserBasket(in);
}
@Override
public UserBasket[] newArray(int size) {
return new UserBasket[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeTypedList(userBasket);
}
public List<BaseCell> getUserBasket() {
return userBasket;
}
public void setUserBasket(List<BaseCell> userBasket) {
this.userBasket = userBasket;
}
/**
* Add to the basket list
* */
public void add(Needy donation) {
if (donation != null)
userBasket.add(donation);
}
/**
* Remove from basket list
* */
public void remove(int position)
{
if (userBasket.size()>0)
userBasket.remove(position);
}
}
从MainActivity发送userBasket arrayList与项目
Navigate.navigateToPaymentPayuStart
（MainActivity.this，userBasket，“购物篮”）；
//使用“ basket”键的userBasket arrayList
在payPayu活动中接收UserBasket
UserBasket userBasket = getIntent（）。getParcelableExtra（“ basket”）;
我如何在PaymentPayuActivity中正确获取UserBasket。
感谢您的帮助
谢谢。
最佳答案
看来您在处理Parcelable实现错误。 e.i.您将两次从Parcel中读取某些变量，这是不允许的。因此，为了改善这一点，我们将尝试使您的代码更简单。由于Needy实际上没有任何变量，因此让BaseCell处理所有可打包实现似乎更好，我尝试为您创建一个模拟程序，因此根据您的其余代码，可能需要一个一点调整。
首先，我删除了Parcelable中的所有Needy实现，只是将其CREATOR指向BaseCell。
public class Needy extends BaseCell {
protected Needy(Parcel in) {
super(in);
cellType ="Needy";
}
// Since Needy doesn't actually store any variables, we don't need a Creator for it.
// Just point it to BaseCell.CREATOR and let it handle it
public static final Parcelable.Creator<BaseCell> CREATOR = BaseCell.CREATOR;
public Needy(String imageUrl, int drawableID, String needyTitle, String needyDescription, int amountOfCollectedDonation, int amountOfTargetDonation, int amountOfDonater, String category, String campaignCode, int maxInstallmentNumber, int price) {
super(imageUrl, drawableID, needyTitle, needyDescription, amountOfCollectedDonation, amountOfTargetDonation, amountOfDonater, category, campaignCode, maxInstallmentNumber,price);
cellType = "Needy";
}
}
然后，让
BaseCell处理所有Parcelable实现，如下所示：public abstract class BaseCell implements Parcelable {
/**
* ALL OF YOUR VARIABLES, GETTERS, SETTERS AND CONSTRUCTORS GOES HERE
*/
@Override
public int describeContents() {
return 0;
}
public static final Parcelable.Creator<BaseCell> CREATOR = new Parcelable.Creator<BaseCell>() {
@Override
public BaseCell createFromParcel(Parcel in) {
String cellType = in.readString();
if (cellType.equals("Needy")) {
return (Needy)new Needy(in);
} else if (cellType.equals("Qurban")) {
return (Qurban)new Qurban(in);
}
return null;
}
@Override
public BaseCell[] newArray(int size) {
return new BaseCell[size];
}
};
protected BaseCell(Parcel in) {
drawableID = in.readInt();
price = in.readInt();
imageUrl = in.readString();
needyTitle = in.readString();
needyDescription = in.readString();
category = in.readString();
campaignCode = in.readString();
maxInstallmentNumber = in.readInt();
userPurchaseAmount = in.readInt();
}
public void writeToParcel(Parcel out, int flags) {
// cellType written first, and read by Creator
out.writeString(cellType);
// the rest is read by the BaseCell constructor
out.writeInt(drawableID);
out.writeInt(price);
out.writeString(imageUrl);
out.writeString(needyTitle);
out.writeString(needyDescription);
out.writeString(category);
out.writeString(campaignCode);
out.writeInt(maxInstallmentNumber);
out.writeInt(userPurchaseAmount);
}
}