intent.putExtra Parcelable 对象和枚举列表

Question

这个问题不同于所有其他问题，因为这里的可打包对象列表是在外部动态创建的，只是在通过 Intent 发送之前。

问题：产品是可包裹的，但定制 List<Product> 不是。如何制作 List Parcelable??

产品

public class Product implements Parcelable {

    public String id;
    public String name;

    public Product(String id, String name) {
        this.id = id;
        this.name = name;
    }

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

    protected Product(Parcel in) {
        id = in.readString();
        name = in.readString();
    }

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

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

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(id);
        parcel.writeString(name);
    }
}

Activity class

Intent intent = new Intent(this, ShowProducts.class);
List<Product> products = getSpecificProducts();

intent.putExtra("PRODUCTS", products); // error

startActivity(intent);

编辑

问题有两部分，不是重复的，另一部分是List<Enum>

public enum Department implements Parcelable {

    SALES("Sales", 0),
    HR("HR", 1),

    public String name;
    public int ordinal;

    Department(String name, int ordinal) {
        this.name = name;
        this.ordinal = ordinal;
    }

    public static final Creator<Department> CREATOR = new Creator<Department>() {
        @Override
        public Department createFromParcel(Parcel in) {
            return Department.values()[in.readInt()];
        }

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

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

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeInt(ordinal);
    }

}

根据建议的答案，我试过了。

List<Department> departments = getSpecificDepartments();

intent.putParcelableArrayListExtra("Departments", departments);

error: incompatible types: List<Department> cannot be converted to ArrayList<? extends Parcelable>

Answer 1

您不需要使 List 可打包。说白了，就是用现有的方法。

final Intent i = new Intent(this,SecondActivity.class);
final ArrayList<Product> list = new ArrayList< Product >();
i.putParcelableArrayListExtra(PRODUCT_KEY, list);
startActivity(i);

以几乎相同的方式检索。

final ArrayList<Product> list = this.getIntent()
            .getParcelableArrayListExtra(PRODUCT_KEY);

更新

回答你最新的问题。您不能在内部传递泛型 List。因为 List 你可以有不同的 collection。要知道系统使用哪种类型，您需要具有显式类型。

// This will work. 
final ArrayList<Department> departments = getSpecificDepartments();
intent.putParcelableArrayListExtra(DEPARTMENTS_KEY, departments);

Answer 2

试试这个

var intent = Intent(this, ActivityB::class.java)
val list = arrayListOf<Person>()
intent.putParcelableArrayListExtra("LIST", list)

Answer 3

像这样使用putParcelableArrayListExtra方法：

ArrayList<Product> products = getSpecificProducts();
intent.putParcelableArrayListExtra("PRODUCTS", products);

intent.putExtra Parcelable 对象和枚举列表

intent.putExtra a list of Parcelable objects and enums

android

parcelable