Question

我有一个由api返回的json填充的列表视图。当我解析json时，我创建了一个新的java对象，它被添加到数组列表中。然后使用数组列表构建列表视图。我可以当前点击列表视图中的一个项目，并获得一个说明项目被点击的祝酒词。

我希望能够检索单个对象，因此我将对象传递给新实例，并在新实例上加载所有对象详细信息以显示给用户。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接口。然后就做：

    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); 
       } 
   });

从第二节课开始：

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

这是如何正确实现接口的example。

Answer 2

应该允许您执行此操作的简单步骤：

跟踪BeerData集合。在您的情况下，这将是beerList。

让BeerData实施Parceable。

（在OnItemClick中使用正确的参数名称。它应该是onItemClick(AdapterView<?> parent, View view, int position, long id)“

在onItemClick

中

onItemClick(AdapterView<?> parent, View view, int position, long id) {
    var beerData = beerList[position];

    Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
    intent.putExtra("BEER!", beerData);
    startActivity(intent);
}

在NextActivities onCreate中：

{
    Bundle extras = getIntent().getExtras();
    BeerData beerData = (BeerData) extras.getParcelable("BEER!);
}

将java对象传递给列表视图上的新android实例单击

2 个答案: