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我已經寫下了這段代碼。不知何故，當我在我的適配器上撥打notifyDatasetChanged時，它不起作用。任何人都可以解釋爲什麼這不起作用。adapter.notifyDataSetChanged（）不起作用
另外我還有另外一個問題（我認爲與此有關）我在創建類HoodID = 27時給出了這個類，但是我該如何做另一種方式，因爲當我這樣做時，我無法選擇我的Spinner中的第一個項目。
package com.example.sander.app;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Context;
import android.location.Location;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.Spinner;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.jjoe64.graphview.GraphView;
import com.jjoe64.graphview.LegendRenderer;
import com.jjoe64.graphview.helper.StaticLabelsFormatter;
import com.jjoe64.graphview.series.BarGraphSeries;
import com.jjoe64.graphview.series.DataPoint;
import com.jjoe64.graphview.series.DataPointInterface;
import com.jjoe64.graphview.series.LineGraphSeries;
import com.jjoe64.graphview.series.OnDataPointTapListener;
import com.jjoe64.graphview.series.Series;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import android.R.layout.*;
import android.widget.Toast;
/**
* Created by Sander on 8-4-2017.
*/
public class GraphFrame extends Fragment implements AdapterView.OnItemSelectedListener {
Integer hoodSelector = 27;
ArrayList<HoodData> hoodDataList = new ArrayList<>();
ArrayList<String> hoodList = new ArrayList<>();
Context mContext;
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
public void refreshFragment(){
hoodDataList.clear();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.detach(this).attach(this).commit();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.fragment_graph,
container, false);
//API Request for all the hoods
getDataFromApi((GraphView) view.findViewById(R.id.graph));
getDataForSpinner((Spinner) view.findViewById(R.id.spinner));
return view;
}
public void setHoodId(Integer hood){
hoodSelector = hood;
}
public void getDataFromApi(final GraphView graph) {
RequestQueue rq = Volley.newRequestQueue(getActivity().getApplicationContext());
String url= "http://test.dontstealmywag.ga/api/damage_or_theft_car_wijk.php?hood_id=" + hoodSelector;
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Do something with the response
try{
JSONObject o = new JSONObject(response);
JSONArray values=o.getJSONArray("");
for (int i = 0; i < values.length(); i++) {
JSONObject jsonObject = values.getJSONObject(i);
hoodDataList.add(new HoodData(jsonObject.getDouble("percentage"), jsonObject.getInt("hood_id"), jsonObject.getInt("year"), jsonObject.getString("hood_name")));
}
} catch (JSONException ex){}
StaticLabelsFormatter staticLabelsFormatter = new StaticLabelsFormatter(graph);
LineGraphSeries<DataPoint> series = new LineGraphSeries<>(new DataPoint[] {
new DataPoint(1, hoodDataList.get(0).getPercentage()),
new DataPoint(2, hoodDataList.get(1).getPercentage()),
new DataPoint(3, hoodDataList.get(2).getPercentage()),
new DataPoint(4, hoodDataList.get(3).getPercentage()),
new DataPoint(5, hoodDataList.get(4).getPercentage())
//new DataPoint(12, 0)
});
// set manual x bounds
staticLabelsFormatter.setHorizontalLabels(new String[] {"2006", "2007","2008","2009","2011"});
//creates custom x-axis
graph.getGridLabelRenderer().setLabelFormatter(staticLabelsFormatter);
graph.setTitle("Wijk " + hoodSelector + " - " + hoodDataList.get(0).getHood_name());
//set nice background color :)
series.setDrawBackground(true);
//shows points at datapoints
series.setDrawDataPoints(true);
//size of the points
series.setDataPointsRadius(10.0f);
series.setOnDataPointTapListener(new OnDataPointTapListener() {
@Override
public void onTap(Series series, DataPointInterface dataPoint) {
Toast.makeText(getActivity(), "Punt "+ dataPoint, Toast.LENGTH_SHORT).show();
}
});
series.setTitle("%");
series.setAnimated(true);
graph.getLegendRenderer().setVisible(true);
graph.getLegendRenderer().setAlign(LegendRenderer.LegendAlign.TOP);
graph.addSeries(series);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// Handle error
}
});
rq.add(stringRequest);
}
public void getDataForSpinner(final Spinner spinner){
RequestQueue rq = Volley.newRequestQueue(getActivity().getApplicationContext());
String url= "http://test.dontstealmywag.ga/api/damage_or_theft_car_wijk.php";
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
// Do something with the response
try{
JSONObject o = new JSONObject(response);
JSONArray values=o.getJSONArray("");
for (int i = 0; i < values.length(); i++) {
JSONObject jsonObject = values.getJSONObject(i);
if (!hoodList.contains(jsonObject.getString("hood_name"))) {
hoodList.add(jsonObject.getString("hood_name"));
}
}
} catch (JSONException ex){}
final ArrayAdapter<String> adapter = new ArrayAdapter<String>(spinner.getContext(), android.R.layout.simple_spinner_item, hoodList);
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
spinner.setPrompt("Title");
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String item = parent.getItemAtPosition(position).toString();
// Showing selected spinner item
for(int i = 1; i < hoodList.size(); i++) {
if (item.equals(hoodList.get(i))) {
setHoodId(i + 27);
adapter.notifyDataSetChanged();
}
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// Handle error
}
});
rq.add(stringRequest);
}
}
您可以嘗試adapter.notifyItemChanged（位置）; –
你期待什麼發生？也就是說，這應該如何工作？當你調用'notifyDataSetChanged（）'時，你沒有改變'Adapter'中的任何東西，所以沒有什麼可更新的。 –
@Mike M.我期望它在按下Spinner時更新我的圖的值 –