ArrayList无法强制转换为Parcelable [英] ArrayList cannot be cast to Parcelable

问题描述

我遇到以下错误：

• Key com..BookStatus预期为可拆分，但值是ArrayList


• ClassCastException：ArrayList不能转换为可包裹的
  ->及其后：无法启动活动-NullPointerException



• ArrayList确实具有BookStatus对象的值（listToPass ）

• Key com..BookStatus expected Parcelable but value was a ArrayList
• ClassCastException: ArrayList cannot be cast to Parcelable -> and therafter: Unable to start Activity - NullPointerException

• the ArrayList do have values of BookStatus Objects (listToPass)

• 键com.example.books.BookStatus期望可拆分，但值是java.util.ArrayList。返回默认值


• 尝试强制转换生成的内部异常：


• java.lang.ClassCastException：java.util.ArrayList无法强制转换为android .os.Parcelable


• 位于com.example.books4locals.SearchActivity.onCreate（SearchActivity.java:46）->这是bundle.getparcelable方法

• Key com.example.books.BookStatus expected Parcelable but value was a java.util.ArrayList. The default value was returned
• Attempt to cast generated internal exception:
• java.lang.ClassCastException: java.util.ArrayList cannot be cast to android.os.Parcelable
• at com.example.books4locals.SearchActivity.onCreate(SearchActivity.java:46) -> which is the bundle.getparcelable method

我该怎么办？

HomeActivity .java

    ArrayList<BookStatus> listToPass = new ArrayList<BookStatus>(); // fill with smthg

        protected void onPostExecute(String result) {

            if (listToPass != null) {

                Intent i = new Intent(getApplicationContext(),
                        SearchActivity.class);
                //              ArrayList<BookStatus> bs = new ArrayList<BookStatus> (Arrays.asList(bArr));

                i.putParcelableArrayListExtra("com.example.books.BookStatus", listToPass);
                startActivity(i);

SearchActivity.java

          protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.searchactivity_main);

            Bundle bundle = getIntent().getExtras();
            ArrayList<BookStatus> bookStatus = bundle
                    .getParcelable("com.example.books.BookStatus");

BookStatus.java

         public class BookStatus implements Parcelable {

        public BookStatus() {
        }

        public BookStatus(Parcel in) {
            this.bookId=in.readInt();

            this.address=in.readString();
            this.name=in.readString();
            this.author=in.readString();
            this.lenderUserId=in.readInt();
            this.isbn=in.readInt();
            this.postcode=in.readString();
            this.town=in.readString();
            this.telnumber=in.readString();
            this.mail=in.readString();
            this.duration=in.readInt();
            }
                        @Override
            public int describeContents() {
                // TODO Auto-generated method stub
                return 0;
            }

            @Override
            public void writeToParcel(Parcel dest, int flags) {
                dest.writeInt(this.bookId);

                dest.writeString(this.address);
                dest.writeString(this.name);
                dest.writeString(this.author);
                dest.writeInt(this.lenderUserId);
                dest.writeInt(this.isbn);
                dest.writeString(this.postcode);
                dest.writeString(this.town);
                dest.writeString(this.telnumber);
                dest.writeString(this.mail);
                dest.writeInt(this.duration);

            }

             public void readFromParcel(Parcel parcel){
                    this.bookId = parcel.readInt();
                    this.address = parcel.readString();

                    this.name = parcel.readString();
                    this.author = parcel.readString();
                    this.lenderUserId = parcel.readInt();
                    this.isbn = parcel.readInt();
                    this.postcode = parcel.readString();
                    this.town = parcel.readString();
                    this.telnumber = parcel.readString();
                    this.mail = parcel.readString();
                    this.duration = parcel.readInt();
                  }




            public static final Parcelable.Creator<BookStatus> CREATOR = new Parcelable.Creator<BookStatus>() {

                 public BookStatus createFromParcel(Parcel in) {
             return new BookStatus(in);
         }

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

推荐答案

尝试更改

 i.putParcelableArrayListExtra("com.example.books.BookStatus", listToPass);

到

i.putExtra("com.example.books.BookStatus", listToPass);

和

 bundle.getParcelable

至

 bundle.getParcelableArrayList

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