java - 刷新 fragment setText 属性

Question

我尝试使用类 Fragment 一切正常，但是当尝试使用从 te 服务器获取的变量时， fragment 不更新值。

这是我的代码:

public class report_fragment extends Fragment {

    private BarChart barChart;
    private ListView list;
    public RequestQueue queue;
    private Float ris;
    String cu;
    Button bSave;

    private String userID,email,name,surname,age,privilegi;
    TextView tExer, tRis;
    String risultato, disciplina;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //just change the fragment_dashboard
        //with the fragment you want to inflate
        //like if the class is HomeFragment it should have R.layout.home_fragment
        //if it is DashboardFragment it should have R.layout.fragment_dashboard
        final View view = inflater.inflate(R.layout.fragment_report_fragment, container, false);

        barChart = (BarChart) view.findViewById(R.id.bargraph);
        tExer = (TextView) view.findViewById(R.id.tExerc);
        tRis = (TextView) view.findViewById(R.id.tRis);

        Bundle b = this.getArguments();
        if (b != null) {

            name = b.getString("name");
            surname = b.getString("surname");
            age = b.getString("age");
            privilegi = b.getString("privilegi");
            userID = b.getString("user");
        }

        Log.d("iduser2", "" + userID);

        graficaDati(userID);

        Last(userID);

        tExer.setText(disciplina);
        tRis.setText(risultato);

        return view;
    }

    private void graficaDati(final String ID) {
        //final TextView gTextView = (TextView) findViewById(R.id.graph);
        // gTextView.append("  entrato in Data");

        String url = "https://anto-mc.000webhostapp.com/atleti_statistiche2.php";
        StringRequest postRequest = new StringRequest(Request.Method.POST, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        try {
                            final ArrayList<BarEntry> barEntries = new ArrayList<>();

                            ArrayList<String> theDates = new ArrayList<>();

                            JSONArray jsonArray = new JSONArray(response);

                            for (int i = 0 ; i < jsonArray.length(); i++) {

                                JSONObject out = jsonArray.getJSONObject(i);


                                String meteo = out.getString("meteo");
                                String dataa = out.getString("data");
                                String risultato = out.getString("risultato");
                                String score = out.getString("punteggio");
                                String tot= out.getString("tot");


                                Log.d("quiqui", ""+tot);

                                barEntries.add(new BarEntry(i, Float.parseFloat(tot)));
                                theDates.add(dataa+"-"+meteo);
                            }

                            BarDataSet set1;
                            set1 = new BarDataSet(barEntries, "Your score");
                            set1.setColors(new int[]{Color.parseColor("#ffffff")});

                            ArrayList<IBarDataSet> dataSets = new ArrayList<IBarDataSet>();
                            dataSets.add(set1);

                            BarData data = new BarData(dataSets);

                            XAxis xAxis = barChart.getXAxis();
                            xAxis.setValueFormatter(new MyCustomXAxisValueFormatter(theDates));

                            xAxis.setGranularity(1f);
                            data.setValueTextSize(10f);
                            data.setBarWidth(0.9f);

                            barChart.setData(data);
                            barChart.getAxisRight().setEnabled(false);
                            barChart.getXAxis().setPosition(XAxis.XAxisPosition.BOTTOM);
                            barChart.invalidate();

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }

                }, new Response.ErrorListener(){
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        })
        {
            @Override
            protected Map<String, String> getParams() {
                Map<String, String>  params = new HashMap<String, String>();
                params.put("userID", ID);
                return params;
            }
        };

        RequestQueue queue = Volley.newRequestQueue(getActivity());
        queue.add(postRequest);
    }

    private void Last(final String ID) {
        //final TextView gTextView = (TextView) findViewById(R.id.graph);
        // gTextView.append("  entrato in Data");

Log.d("ciaoo","sei qui");

        String url = "https://anto-mc.000webhostapp.com/last.php";
        StringRequest postRequest = new StringRequest(Request.Method.POST, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        try {
                            final ArrayList<BarEntry> barEntries = new ArrayList<>();

                            ArrayList<String> theDates = new ArrayList<>();
                            Log.d("ciaoo","sei qui2");
                            JSONArray jsonArray = new JSONArray(response);

                            for (int i = 0 ; i < jsonArray.length(); i++) {

                                JSONObject out = jsonArray.getJSONObject(i);
                                Log.d("ciaoo","sei qui2" +""+out);

                                String meteo = out.getString("meteo");
                                disciplina = out.getString("disciplina");
                                risultato = out.getString("risultato");
                                String score = out.getString("punteggio");
                                String tot= out.getString("tot");



                                Log.d("queryris",""+disciplina + "  "+ risultato);
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }

                }, new Response.ErrorListener(){
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        })
        {
            @Override
            protected Map<String, String> getParams() {
                Map<String, String>  params = new HashMap<String, String>();
                params.put("userID", ID);
                return params;
            }
        };

        RequestQueue queue = Volley.newRequestQueue(getActivity());
        queue.add(postRequest);
    }
}

我收到了变量“risultato and disciplina”，并且在第二次浏览此 fragment 后我看到了正确的值。

我第一次看到 null 变量。

我尝试使用 fragment 的刷新，但它不起作用。

条形图工作正常，但 setText 不工作。我试着像条形图一样做同样的事情，但我失败了。

有人有什么建议吗？谢谢。

Answer 1

您需要在 onResponse 函数中设置文本。在网络调用完成之前，这些值不可用。所以 Last 函数中的 onResponse 函数应该如下所示。

private void Last(final String ID) {
    //final TextView gTextView = (TextView) findViewById(R.id.graph);
    // gTextView.append("  entrato in Data");

    Log.d("ciaoo","sei qui");

    String url = "https://anto-mc.000webhostapp.com/last.php";
    StringRequest postRequest = new StringRequest(Request.Method.POST, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        final ArrayList<BarEntry> barEntries = new ArrayList<>();

                        ArrayList<String> theDates = new ArrayList<>();
                        Log.d("ciaoo","sei qui2");
                        JSONArray jsonArray = new JSONArray(response);

                        for (int i = 0 ; i < jsonArray.length(); i++) {

                            JSONObject out = jsonArray.getJSONObject(i);
                            Log.d("ciaoo","sei qui2" +""+out);

                            String meteo = out.getString("meteo");
                            disciplina = out.getString("disciplina");
                            risultato = out.getString("risultato");
                            String score = out.getString("punteggio");
                            String tot= out.getString("tot");

                            Log.d("queryris",""+disciplina + "  "+ risultato);
                        }

                        // Set the text here when it is available
                        tExer.setText(disciplina);
                        tRis.setText(risultato);

                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }

            }, new Response.ErrorListener(){
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    })

    {
        @Override
        protected Map<String, String> getParams()
        {
            Map<String, String>  params = new HashMap<String, String>();
            params.put("userID", ID);

            return params;
        }
    };
    RequestQueue queue = Volley.newRequestQueue(getActivity());
    queue.add(postRequest);
}

关键思想是在您的 API 调用返回其中包含一些值后，在值可用后设置文本。当您调用服务器 API 时，它是在 UI 线程以外的另一个线程中执行的。它不会像您期望的那样在 onCreateView 函数内停止执行。

希望对您有所帮助。