java - 在 ListView 单击时将 java 对象传递给新的 android 实例

Question

我有一个 ListView ，由从 api 返回的 json 填充。当我解析 json 时，我创建了一个新的 java 对象，该对象被添加到数组列表中。然后使用数组列表来构建 ListView 。我现在可以点击 ListView 中的一个项目，然后 toast 说一个项目被点击了。

我希望能够检索单个对象，因此我可以将对象传递给新实例并将所有对象详细信息加载到新实例上以显示给用户。我怎样才能像这样传递一个对象？

我的代码:

private class ReadJSONResult extends AsyncTask
    <String, Void, String> {
        protected String doInBackground(String... urls) {
            return readJSONFeed(urls[0]);
        }

        protected void onPostExecute(String result) {
            try {
                System.out.println(result);
                Log.d("asycTask", "[ Gets into asyc task ]");
                ///get 
                Log.d("search", "[ check if we get search results ]");
                Log.d("search", "[" + result + "]");

                JSONObject json = new JSONObject(result);

                //acces listview
                lv = (ListView) findViewById(android.R.id.list);

                //make array list for beer
                List<BeerData> beerList = new ArrayList<BeerData>();



                //get json items
                for(int i = 0; i < json.getJSONArray("data").length(); i++) {

                    String beerId = GetBeerDataFromJSON(i,"id", json);
                    String beerName = GetBeerDataFromJSON(i,"name", json);
                    String beerDescription = GetBeerDataFromJSON(i,"description" , json);
                    String beerAbv = GetBeerDataFromJSON(i,"abv" , json);
                    String beerIbu = GetBeerDataFromJSON(i,"ibu" , json);
                    String beerIcon = GetBeerIconsFromJSON(i, "icon",json );
                    String beerMediumIcon = GetBeerIconsFromJSON(i, "medium",json );
                    String beerGlass = GetBeerGlassFromJSON(i, json );
                    String beerStyle = GetBeerStyleFromJSON(i,"name", json );
                    String beerStyleDescription = GetBeerStyleFromJSON(i,"description", json );
                    String beerBreweryId = GetBeerBreweryInfoFromJSON(i, "id", json );
                    String beerBreweryName = GetBeerBreweryInfoFromJSON(i, "name", json );
                    String beerBreweryDescription = GetBeerBreweryInfoFromJSON(i, "description", json );
                    String beerBreweryWebsite = GetBeerBreweryInfoFromJSON(i, "website", json );
                    String beerBreweryYear = GetBeerBreweryInfoFromJSON(i, "established", json );



                    //create beer object
                    BeerData thisBeer = new BeerData(beerName, beerId, beerDescription, beerAbv, beerIbu, beerIcon,
                            beerMediumIcon, beerGlass, beerStyle, beerStyleDescription, beerBreweryId, beerBreweryName,
                            beerBreweryDescription, beerBreweryYear, beerBreweryWebsite);

                    //add beer to list
                    beerList.add(thisBeer);


                }

                //update listview
                ArrayAdapter<BeerData> adapter1 = new ArrayAdapter<BeerData>(MainActivity.this, R.layout.list_item, R.id.itemName, beerList);
                lv.setAdapter(adapter1);

                //set up clicks
                lv.setOnItemClickListener(new OnItemClickListener() {


                    @Override
                    public void onItemClick(AdapterView<?> arg0, View arg1,
                            int arg2, long arg3) {

                        //on item click do this
                        Toast.makeText(MainActivity.this, "click worked", Toast.LENGTH_SHORT).show();
                    } 
                    });






            } catch (Exception e) {
                Log.d("ReadBeerDataTask", e.getLocalizedMessage());
            }          
        }
    }

Answer 1

让您的BeerData 类实现Parcelable界面。然后就这样做:

    lv.setOnItemClickListener(new OnItemClickListener() {    
       @Override
       public void onItemClick(AdapterView<?> arg0, View arg1,
                                int arg2, long arg3) {
              Intent i = new Intent(MainActivity.this, SecondActivity.class); 
              i.putExtra("myBeerObject", lv.getItemAtPosition(arg2));   
              startActivity(i); 
       } 
   });

来自第二类:

Bundle b = getIntent().getExtras(); 
BeerData beer = b.getParcelable("myBeerObject"); 

这是一个 example如何正确实现接口(interface)。