如何使用 Intent 将一组对象从一个活动传递到另一个活动？ [复制]

Question

• 我正在制作一个应用程序，其中数据库产品将被添加到一个 xml 文件中。
  • 查询xml文件后，这些产品将被添加到一个数组中。
  • 此数组将被发送到其他活动，例如 MainActivity for Menu，但我无法通过 Intent 发送数组。

    //MainActivity
        public class MainActivity extends AppCompatActivity {
         public ArrayList<Produto> array;
            private File Produtos;
            private FileOutputStream fileos;

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

                array = new ArrayList<Produto>();

        //if there is no xml file this goes to the database and adds the products in an xml file
                if ((Produtos.exists() == false))
                AdicionarProdutosXML();

        //query xml file and add the products in an array
                ConsultarFicheirosXml();

//pass the array from one activity to another
                Intent i=new Intent(MainActivity.this,Menu.class);
                i.putExtra("array",array);
                startActivity(i);
            }

            public void ConsultarFicheirosXml()
            {
                    int tipo=0;
                    String nome="";
                    float pvp=0;
                    int quantidade;
                    int eventType=0;
                    XmlPullParser parser=null;
                    File file=null;
                    FileInputStream fis=null;
                    XmlPullParserFactory factory;

                    try {
                        factory = XmlPullParserFactory.newInstance();
                        factory.setNamespaceAware(true);
                        parser = factory.newPullParser();
                        file = new File("/mnt/sdcard/Produtos.xml");

                        try {
                            fis = new FileInputStream(file);
                        } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                        parser.setInput(new InputStreamReader(fis));
                        eventType=parser.getEventType();

                    } catch (XmlPullParserException e) {
        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    while(eventType!=XmlPullParser.END_DOCUMENT) {

                        switch (eventType) {
                            case XmlPullParser.START_DOCUMENT:

                                break;
                            case XmlPullParser.START_TAG:

                                if (parser.getName().equalsIgnoreCase("Tipo")) {
                                    Produto p = new Produto();
                                    try {
                                       tipo= Integer.valueOf(parser.nextText());
                                       parser.nextTag();
                                       nome=parser.nextText();
                                       parser.nextTag();
                                       pvp=Float.valueOf(parser.nextText());
                                       parser.nextTag();
                                       quantidade=Integer.valueOf(parser.nextText());
                                       parser.nextTag();

                                       p.tipo=tipo;
                                       p.nome=nome;
                                       p.pvp=pvp;
                                       p.quantidade=quantidade;
                                       array.add(p);


                                    } catch (XmlPullParserException e) {
                                // TODO Auto-generated catch block
                                        e.printStackTrace();
                                    } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                        e.printStackTrace();
                                    }


                                }
                                break;
                            case XmlPullParser.END_TAG:

                                break;

                            case XmlPullParser.END_DOCUMENT:

                                break;
                        }
                        try {
                            eventType = parser.next();
                        } catch (XmlPullParserException e) {
        // TODO Auto-generated catch block
                            e.printStackTrace();
                        } catch (IOException e) {
        // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }
            }

        //another activity

        public class Menu extends AppCompatActivity {

            public ArrayList<Produto> arrayList;

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

             Bundle produtos=getIntent().getExtras();

            }

Answer 1

使 paracellable（在 android 中推荐）或可序列化模型类。然后就可以在activity之间传递对象了。

Answer 2

使用意图不是一个好主意。使用事件总线 https://github.com/greenrobot/EventBus