Question

我通过Json收到了LatLang，但现在我想在Postexecute方法的地图上显示这是我的代码

 ServiceHandler serviceClient = new ServiceHandler();
        Log.d("url: ", "> " + URL_ITEMS);
        String json = serviceClient.makeServiceCall(URL_ITEMS, ServiceHandler.GET);
        // print the json response in the log
        Log.d("Get match fixture resps", "> " + json);
        if (json != null) {
            try {
                Log.d("try", "in the try");
                JSONObject jsonObj = new JSONObject(json);
                Log.d("jsonObject", "new json Object");
                // Getting JSON Array node
                matchFixture = jsonObj.getJSONArray(TAG_FIXTURE);
                Log.d("json aray", "user point array");
                int len = matchFixture.length();
                Log.d("len", "get array length");
                for (int i = 0; i < matchFixture.length(); i++) {
                    JSONObject c = matchFixture.getJSONObject(i);
                    Double matchId = Double.parseDouble(c.getString(TAG_MATCHID));
                    Log.d("matchId", String.valueOf(matchId));
                    Double teamA = Double.valueOf(c.getString(TAG_TEAMA));
                    Log.d("teamA", String.valueOf(teamA));

                    //  hashmap for single match
                    HashMap<String, String> matchFixture = new HashMap<String, String>();
                    // adding each child node to HashMap key => value
                    matchFixture.put(TAG_MATCHID, String.valueOf(matchId));
                    matchFixture.put(TAG_TEAMA, String.valueOf(teamA));

                    matchFixtureList.add(new LatLng(matchId, teamA));


                }
            } catch (JSONException e) {
                Log.d("catch", "in the catch");
                e.printStackTrace();
            }
        } else {
            Log.e("JSON Data", "Didn't receive any data from server!");
        }
        return null;
    }


    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        for (LatLng point:matchFixtureList){
            mMap.addMarker(new MarkerOptions().position(point).title("chexk"));
        }

        // mMap.addMarker(new MarkerOptions().position(pakistan).title("Marker in pakistn"));
        //mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(16));
        }

那么如何在地图上显示标记我在日志中收到所有lat和lang但在logcat中显示nullpointer dfdfd

Answer 1

您在（我假设的）points = [ [2.9600000000000004, 6.3999999999999995], [2.72, 4.8], [2.48, 3.1999999999999997], [2.2399999999999998, 1.5999999999999996], [4.32, 6.3999999999999995], [4.24, 4.8], [4.16, 3.1999999999999997], [4.08, 1.5999999999999996], [5.68, 6.3999999999999995], [5.759999999999999, 4.8], [5.84, 3.1999999999999997], [5.92, 1.5999999999999996], [7.04, 6.3999999999999995], [7.28, 4.8], [7.5200000000000005, 3.1999999999999997], [7.76, 1.5999999999999996], [0, 0], [2.0, 0.0], [4.0, 0.0], [6.0, 0.0], [8.0, 0.0], [10, 0], [2, 8], [3.2, 8.0], [4.4, 8.0], [5.6, 8.0], [6.8, 8.0], [8, 8], [2, 8], [1.6, 6.4], [1.2, 4.8], [0.7999999999999998, 3.1999999999999993], [0.3999999999999999, 1.5999999999999996], [0, 0], [8, 8], [8.4, 6.4], [8.8, 4.8], [9.2, 3.1999999999999993], [9.6, 1.5999999999999996], [10, 0] ]方法中返回了null。

尝试将doInBackground()更改为：

doInBackground

Answer 2

检查教程中的所有步骤。交叉检查你是否已经遵循了一切。 http://wptrafficanalyzer.in/blog/adding-marker-at-user-input-latitude-and-longitude-in-google-map-android-api-v2/

对Keystore部分施加更多压力。是否与您使用或其他

相同

LatLang通过Json NullPointer

2 个答案: