Question

Android编程新手。我有2个对象必须是Parcelable，称为Book和Author。我相当肯定我正确地准备了它们。我希望得到一些帮助：

创建图书

将他们发送到新活动

public class Book implements Parcelable {

public int id;
public String title;
public ArrayList<Author> authors = new ArrayList<Author>();
public int Aflags;
public String isbn;
public String price;

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

@Override
public void writeToParcel(Parcel out, int flags) {
    out.writeInt(id);
    out.writeString(title);
    out.writeTypedList(authors);
    out.writeString(isbn);
    out.writeString(price);
}

private Book(Parcel in) {
    id = in.readInt();
    title = in.readString();
    in.readTypedList(authors, Author.CREATOR);
    isbn = in.readString();
    price = in.readString();
}


public static final Parcelable.Creator<Book> CREATOR = new Parcelable.Creator<Book>() {
    public Book createFromParcel(Parcel in) {
        return new Book(in);
    }
    public Book[] newArray(int size) {
        return new Book[size];
    }
};

@Override
public String toString()
{
    return title + " Price: " + price;
}

 }

现在作者：

public class Author implements Parcelable {

// TODO Modify this to implement the Parcelable interface.
// I think I was able to accomplish this
// NOTE: middleInitial may be NULL!

public String firstName;

public String middleInitial;

public String lastName;

@Override
public void writeToParcel(Parcel out, int flags) {
    out.writeString(firstName);
    if (middleInitial.length() == 0)
        out.writeString(middleInitial);
    out.writeString(lastName);
}

private Author(Parcel in)
{
    firstName = in.readString();
    if (in.dataSize() > 2)
        middleInitial = in.readString();
    lastName = in.readString();
}

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

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

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


  }

我不知道为什么我感到难过，但我无法找到如何实施我的包裹来制作这本书并继续前进。这是试图让书籍将其发送到另一个活动的活动：

public class AddBookActivity extends Activity {

// Use this as the key to return the book details as a Parcelable extra in the result intent.
public static final String BOOK_RESULT_KEY = "book_result";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.add_book);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.search_menu, menu);
    // COMPLETED TODO provider SEARCH and CANCEL options
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    super.onOptionsItemSelected(item);
    // TODO
    switch (item.getItemId()) {
    case R.id.search:
    // SEARCH: return the book details to the BookStore activity
        this.searchBook();
    return true;
    case R.id.cancel:
        new AlertDialog.Builder(this)
        .setTitle("Cancel Search")
        .setMessage("Are you sure you want to cancel your search?")
        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) { 
                AddBookActivity.this.finish();
            }
         })
        .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) { 
                // do nothing
            }
         })
        .setIcon(R.drawable.ic_dialog_alert)
         .show();
    // CANCEL: cancel the search request
    return true;
    }
    return false;
}

public Book searchBook(){
    /*
     * Book object with the search criteria and return that.
    */
    EditText editText = (EditText) findViewById(R.id.search_title);
    String title = editText.getText().toString();
    editText = (EditText) findViewById(R.id.search_author);
    String author = editText.getText().toString();
    editText = (EditText) findViewById(R.id.search_isbn);
    int isbn = Integer.parseInt(editText.getText().toString());
    Parcel p = Parcel.obtain();
    p.writeInt(isbn);
    p.writeString(title);
    p.writeString(author);
    p.writeString(editText.getText().toString());
    p.writeString("$15.00");
    return null;
}

}

Answer 1

如果您尝试通过使用Intent将parcelable对象发送到新的Activity，它应该像调用intentobject.putExtra（“key”，parcelableobject）一样简单。 Android将为您处理其余部分，因为您的对象实现了Parcelable接口。

Answer 2

用于发送数据使用：

Intent intent = new Intent(this,NewActivity.class);
intent.putExtra("listOfBook", bookList); // sending list
intent.putExtra("objOfBook", bookObj);  // sending obj
startActivity(intent);

并获得了：

ArrayList<Book> myList = getIntent().getParcelableExtra("listOfBook"); // getting list
Book bookObj = getIntent().getParcelableExtra("objOfBook"); // getting obj

使用我的代码编辑以下函数：

public Book searchBook(){
    /*
     * Book object with the search criteria and return that.
    */
    EditText editText = (EditText) findViewById(R.id.search_title);
    String title = editText.getText().toString();
    editText = (EditText) findViewById(R.id.search_author);
    String author = editText.getText().toString();
    editText = (EditText) findViewById(R.id.search_isbn);
    int isbn = Integer.parseInt(editText.getText().toString());
    Book b = new Book();
    b.SetIsbn(isbn);
    b.SetTitle(title);
    b.SetAuthor(author);
    b.SetPrice("$15.00")
    // i don't know what for is last line
    return b;
}

创建用户定义的Parcelable对象并实现功能

2 个答案: