Question

我一直在努力试图在Android中解决Fragments问题。目前我已经创建了一个按钮菜单，允许用户在片段之间切换。然后，每个片段将允许用户使用特定于该片段的搜索条件从服务器获取JSON数组。

理想情况下，在每次搜索之后，结果将保留在内存中，以便用户可以使用菜单在片段之间切换。由于片段将使用当前所有位于MainActivity中的相同方法，如何从片段内部调用MainActivity中的方法？

我在Activity中的方法代码：

  public ArrayList<Eatery> fillArray() {

    String line;
    Eatery eatery = new Eatery("hello","hello","hello","hello","hello",
            "hello","hello","hello","hello","hello");
    ArrayList<Eatery> eateryList = new ArrayList<>();

    if (getConnection() == true) {
        try {

            URL nameURL = new URL("http://sandbox.kriswelsh.com/hygieneapi/hygiene.php?op=s_name&name=Wok%20This%20Way");
            HttpURLConnection postcodeConnection = (HttpURLConnection) nameURL.openConnection();
            InputStreamReader isr = new InputStreamReader(postcodeConnection.getInputStream());
            BufferedReader nameBF = new BufferedReader(isr);

            while ((line = nameBF.readLine()) != null) {
                JSONArray ja = new JSONArray(line);
                for (int i = 0; i < ja.length(); i++) {

                    JSONObject jo = ja.getJSONObject(i);
                    String id = jo.getString("id");
                    String businessName = jo.getString("BusinessName");
                    String addressLine1 = jo.getString("AddressLine1");
                    String addressLine2 = jo.getString("AddressLine2");
                    String addressLine3 = jo.getString("AddressLine3");
                    String postcode = jo.getString("PostCode");
                    String ratingValue = jo.getString("RatingValue");
                    String ratingDate = jo.getString("RatingDate");
                    String lati = jo.getString("Latitude");
                    String longi = jo.getString("Longitude");
                    eatery.setId(id);
                    eatery.setBusinessName(businessName);
                    eatery.setAddressLine1(addressLine1);
                    eatery.setAddressLine2(addressLine2);
                    eatery.setAddressLine3(addressLine3);
                    eatery.setPostcode(postcode);
                    eatery.setRatingValue(ratingValue);
                    eatery.setRatingDate(ratingDate);
                    eatery.setLati(lati);
                    eatery.setLati(longi);
                    eateryList.add(eatery);
                }
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    } else {
        Toast nameToast = Toast.makeText(getApplicationContext(), "Error: No Active Connection", Toast.LENGTH_LONG);
        nameToast.show();
    }

    return (eateryList);
}

Answer 1

非常简单：

if (getActivity() instanceof MainActivity) {    
    ((MainActivity) getActivity()).yourMethod(...);
}

Answer 2

你可以这样打电话;

（（MyActivityClass）getActivity（））方法名（）;

Answer 3

正确的沟通方式是interface。查看此video以完成工作。如果您不熟悉Android开发，整个系列都值得一试。

如何从片段

3 个答案: