Question

我想将对象oManagement从活动X传递给Y.

在X：

oManagement = new OrdersManagement();
myIntent = new Intent(this, Y.class);

然后我用单独的线程填充我的oManagement对象。

然后我等待oManagement填写并开始另一项活动：

while (oManagement.allOrders.size() == 0) {
    try {
        Thread.sleep(5);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    if (oManagement.allOrders.size() > 0) {
        myIntent.putExtra("OrdersManagementObject", oManagement);
        this.startActivity(myIntent);
    }
}

在我的Y活动中：

Bundle b = this.getIntent().getExtras();
if (b != null) {
    oManagement = b.getParcelable("OrdersManagementObject");
}

现在惊喜 - ＆gt; oManagement不是null，但是oManagement.allOrders.size()是0！ :(所以我传递了我的对象，但是ArrayList里面的对象是0（在传递的时刻是该数组中的1个元素）。

如何解决这个问题？

编辑：

OrdersManagement类：

public class OrdersManagement implements Parcelable {

    public ArrayList<QuantorsOrder> allOrders  = new ArrayList<QuantorsOrder>();

    public OrdersManagement() {
    }

    public OrdersManagement(Parcel in) {
    }

    public static final Creator<OrdersManagement> CREATOR = new Creator<OrdersManagement>() {
        @Override
        public OrdersManagement createFromParcel(Parcel in) {
            return new OrdersManagement(in);
        }

        @Override
        public OrdersManagement[] newArray(int size) {
            return new OrdersManagement[size];
        }
    };

    public void updateListOfOrders(JSONArray jsonArray) throws JSONException {
        if (jsonArray != null && jsonArray.length() > 0)
        {
            JSONObject json;
            for (int i = 0; i < jsonArray.length(); i++)
            {
                json = (JSONObject)jsonArray.get(i);
                if(!IsOrderAlreadyExists(json))
                    addOrder(json);
            }
        }
    }

    private boolean IsOrderAlreadyExists(JSONObject json) throws JSONException
    {
        if (allOrders.isEmpty())
            return false;
        else
        {
            for(QuantorsOrder order : allOrders)
            {
                if (String.valueOf(order.getId()).equals(json.get("id").toString()))
                {
                    return true;
                }
            }
            return false;
        }
    }

    private void addOrder(JSONObject json) throws JSONException {
        allOrders.add(new QuantorsOrder(json));
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
    }
}

Answer 1

您的QuantorsOrder也应该实施Parcelable。在writeToParcel()方法中，您应该编写列表并在构造函数中读取它，如下所示：

public void writeToParcel(Parcel out, int flags) {
    out.writeTypedList(allOrders);
}

private OrdersManagement (Parcel in) {
    in.readTypedList(allOrders, QuantorsOrder.CREATOR);
}

您还应该在QuantorsOrder课程中实现写作和阅读字段的逻辑。以下是简单类的示例：

   public class MyParcelable implements Parcelable {
     private int mData;

     public int describeContents() {
         return 0;
     }

     public void writeToParcel(Parcel out, int flags) {
         out.writeInt(mData);
     }

     public static final Parcelable.Creator<MyParcelable> CREATOR
             = new Parcelable.Creator<MyParcelable>() {
         public MyParcelable createFromParcel(Parcel in) {
             return new MyParcelable(in);
         }

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

     public MyParcelable(Parcel in) {
         mData = in.readInt();
     }
 }

这里的主要内容发生在writeToParcel(...)方法和构造函数public MyParcelable(Parcel in)中。

我无法从一个Activity到另一个Activity（android）

1 个答案: