旋转屏幕时,我的ListView不会保存;使用parcelable interface和onSaveInstanceState

用户提交查询并搜索api后,将填充一个列表。但当我切换到风景时,它消失了。我需要设法保存它。我实现了一个可打包的接口,并添加了覆盖和恢复onSaveInstanceState的方法。我在这里所做的对我的应用程序的性能没有任何影响,不幸的是,我只是对新代码不够熟悉,不知道我做错了什么。我在网上找到的大部分信息都是假设我知道的比我知道的多,哈哈。如有任何建议,不胜感激。谢谢

public class MainActivity extends AppCompatActivity {

Book myClass;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Find the ListView.xml in the view hierarchy.
    ListView listItemView = (ListView) findViewById(R.id.list);

    // Shows an empty text view when there's nothing to show
    mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
    listItemView.setEmptyView(mEmptyStateTextView);

    // Create a new adapter that takes an empty list of books as input
    mAdapter = new BookAdapter(this, new ArrayList<Book>());

    // Hide loading indicator because the data has been loaded
    View loadingIndicator = findViewById(R.id.loading_indicator);
    loadingIndicator.setVisibility(View.GONE);

    // Populates the adapter with the list view xml file
    listItemView.setAdapter(mAdapter);

    handleIntent(getIntent());
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelable("obj", myClass);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    myClass=savedInstanceState.getParcelable("obj");
}

和我的自定义类:

public class Book implements Parcelable {

private int mData;

// Book title
private String mTitle;

// Book author
private String mAuthor;

/**
 * Create a new Book object
 * @param title is the title of the book
 * @param author is the author of the book
 */
public Book(String title, String author) {
    mTitle = title;
    mAuthor = author;
}

//Get the title of the book.
public String getTitle() {
    return mTitle;
}

//Get the author of the book.
public String getAuthor() {
    return mAuthor;
}

protected Book(Parcel in) {
    mTitle = in.readString();
    mAuthor = in.readString();
}

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

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(mTitle);
    dest.writeString(mAuthor);
}

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

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

和我的列表适配器:

public class BookAdapter extends ArrayAdapter<Book> {

//constructor
public BookAdapter(Activity context, ArrayList<Book> books) {
    super(context, 0, books);
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

    // control-O automatically created
    View listItemView = convertView;
    if(listItemView == null) {
        listItemView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent, false);
    }

    // Get the book at the current position on the list
    Book currentBook = getItem(position);

    // Find the TextView in the list_item.xml with this ID
    TextView titleTextView = (TextView) listItemView.findViewById(R.id.title_text);
    // Get the title from the current Book object and set it on the TextView
    titleTextView.setText(currentBook.getTitle());

    // Find the TextView in the list_item.xml with this ID
    TextView authorTextView = (TextView) listItemView.findViewById(R.id.author_text);
    // Get the title from the current Book object and set it on the TextView
    authorTextView.setText(currentBook.getAuthor());

    // Return the whole list item layout (containing 2 TextViews)
    // so that it can be shown in the ListView
    return listItemView;
}
}