使用 Intent 时传递数组数据为空

Question

我想在 2 activity之间传递arraylist，但我遇到了一个问题

在FirstActivity中，ArrayList不为空，但在SecondActivity中它是空的，我不知道发生了什么

我的意图：

Intent intent = new Intent(mContext, NewContactActivity.class);
intent.putParcelableArrayListExtra("CONTACT_ARRAY", mData);
mContext.startActivity(intent);

我的第二个活动：

Intent intent = getIntent();
ArrayList<Contact> lstContact = this.getIntent().getParcelableArrayListExtra("CONTACT_ARRAY");
edtPhone.setText(lstContact.get(0).getPhone());

我的联系人类：

public class Contact implements Parcelable {
    private String id;
    private String Name;
    private String Fname;
    private String Phone;
    private String Email;

    public Contact(String id, String Name, String Fname, String Phone, String Email) {
        this.id = id;
        this.Name = Name;
        this.Fname = Fname;
        this.Email = Email;
        this.Phone = Phone;
    }
    public Contact(Parcel in) {
        this.id = in.readString();
        this.Name = in.readString();
        this.Fname = in.readString();
        this.Email = in.readString();
        this.Phone = in.readString();
    }
    //Getter
    public String getId() { return id; }
    public String getName() {
        return Name;
    }
    public String getFname() {
        return Fname;
    }
    public String getEmail() {
        return Email;
    }
    public String getPhone() {
        return Phone;
    }
    //Setter
    public void setName(String name) {
        this.Name = name;
    }
    public void setFname(String fname) {
        Fname = fname;
    }
    public void setEmail(String email) {
        Email = email;
    }
    public void setPhone(String phone){ Phone = phone; }
    @Override
    public int describeContents() {
        return 0;
    }
    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(id);
        dest.writeString(Name);
        dest.writeString(Fname);
        dest.writeString(Phone);
        dest.writeString(Email);
    }
    public static final Parcelable.Creator<Contact> CREATOR = new Parcelable.Creator<Contact>() {
        public Contact createFromParcel(Parcel in)
        {
            return new Contact(in);
        }
        public Contact[] newArray(int size)
        {
            return new Contact[size];
        }
    };
}

我该如何解决这个问题？非常感谢

Answer 1

你必须传递数组列表而不是单个对象

ArrayList<Contact> lstContact = createContactList();
i.putParcelableArrayListExtra("CONTACT_ARRAY", (ArrayList) lstContact );

在第二次活动中

 ciArr = (List) i.getParcelableArrayListExtra("CONTACT_ARRAY");

Answer 2

将this.getIntent()替换为您的intent。你根本没有使用它。

Answer 3

您必须在构造函数和 writeToParcel 函数中保持相同的顺序。

 @Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(id);
    dest.writeString(Name);
    dest.writeString(Fname);
    dest.writeString(Email);
    dest.writeString(Phone);

}

Answer 4

尝试使用以下代码。

private void gotoNextActivity() {
    Intent intent=new Intent(this,NewContactActivity.class);
    Bundle bundle = new Bundle();
    bundle.putParcelableArrayList("CONTACT_ARRAY", contactsList);
    intent.putExtras(bundle);
    startActivity(intent);
}

新联系人活动.class

  ArrayList<BeanClass> listFromActivity1=new ArrayList<>(); 
  listFromActivity1=this.getIntent().getExtras().getParcelableArrayList("CONTACT_ARRAY");
  if (listFromActivity1 != null) {
       Log.d("Contact List",""+listFromActivity1.toString());
     }