我正在尝试从json加载ListView到post请求，api工作正常，代码中也没有错误，但不知何故ListView没有填充任何数据。请帮帮我。
这是我的活动。
public class Reciepe extends AppCompatActivity {
String Barname;
String finalJson;
private ListView reciepeListView;
private ProgressDialog loading;
String url = "http://thehostels.in/Foody/reciepe_json.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_reciepe);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
JSONTask();
toolbar.setBackgroundColor(Color.parseColor("#FFBC03"));
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
DisplayImageOptions options = new DisplayImageOptions.Builder()
.cacheInMemory(true)
.cacheOnDisk(true)
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(Reciepe.this)
.defaultDisplayImageOptions(options)
.build();
com.nostra13.universalimageloader.core.ImageLoader.getInstance().init(config);
reciepeListView = (ListView) findViewById(R.id.list_recipe);
Intent intent = getIntent();
if (intent != null) {
Barname = intent.getStringExtra("Type");
Log.e("Type", Barname);
}
if (Barname != null) {
switch (Barname) {
case "Punjabi":
getSupportActionBar().setTitle("Punjabi");
break;
case "Chinese":
getSupportActionBar().setTitle("Chinese");
break;
case "South Indian":
getSupportActionBar().setTitle("South Indian");
break;
case "Gujarati":
getSupportActionBar().setTitle("Gujarati");
break;
case "Chicken":
getSupportActionBar().setTitle("Chicken");
break;
}
}
}
public void JSONTask() {
ProgressDialog loading;
RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
StringRequest sr = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.e("response : ", response);
JSONObject parentObject = null;
try {
parentObject = new JSONObject(response);
} catch (JSONException e) {
e.printStackTrace();
}
JSONArray parentArray = null;
try {
assert parentObject != null;
parentArray = parentObject.getJSONArray("list");
} catch (JSONException e) {
e.printStackTrace();
}
List<Listview_reciepe_conveyer> fixture_conveyerList = new ArrayList<Listview_reciepe_conveyer>();
assert parentArray != null;
for (int i = 0; i < parentArray.length(); i++) {
JSONObject finalObject = null;
try {
finalObject = parentArray.getJSONObject(i);
} catch (JSONException e) {
e.printStackTrace();
}
Listview_reciepe_conveyer fixtureList = new Listview_reciepe_conveyer();
try {
assert finalObject != null;
fixtureList.setImage(finalObject.getString("image"));
} catch (JSONException e) {
e.printStackTrace();
}
try {
fixtureList.setFood(finalObject.getString("food"));
} catch (JSONException e) {
e.printStackTrace();
}
try {
fixtureList.setPrice(finalObject.getString("price"));
} catch (JSONException e) {
e.printStackTrace();
}
fixture_conveyerList.add(fixtureList);
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("response : ", error.toString());
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("Dish", Barname);
Log.d("Dish", ": " + params.toString());
return params;
}
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Content-Type", "application/x-www-form-urlencoded");
return params;
}
};
Log.d("Leaderboard", "Req : " + sr.getUrl());
requestQueue.add(sr);
}
}
ListAdapter类
public class ListAdapter extends ArrayAdapter<Listview_reciepe_conveyer> {
private List<Listview_reciepe_conveyer> reciepe_conveyerList;
private int resource;
private LayoutInflater inflater;
public ListAdapter(Context context, int resource, List<Listview_reciepe_conveyer> objects) {
super(context, resource, objects);
reciepe_conveyerList = objects;
this.resource = resource;
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = inflater.inflate(resource, null);
}
ImageView food_photo;
final TextView food,price;
food_photo = (ImageView)convertView.findViewById(R.id.food_photo);
food = (TextView)convertView.findViewById(R.id.food_name);
price = (TextView)convertView.findViewById(R.id.food_price);
ImageLoader.getInstance().displayImage(reciepe_conveyerList.get(position).getImage(), food_photo);
food.setText(reciepe_conveyerList.get(position).getFood());
String newprice= ("Rs."+reciepe_conveyerList.get(position).getPrice());
price.setText(newprice);
return convertView;
}
}
Listview_conveyer类
public class Listview_reciepe_conveyer {
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String getFood() {
return food;
}
public void setFood(String food) {
this.food = food;
}
private String image;
private String food;
private String price;
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
}
代码中没有错误，但ListView为空。我正在使用凌空库来获取数据，而api正在完美运行。我已经检查过邮差很好。请指导我。谢谢。
答案 0 :(得分：0)
以下是您的代码的固定版本。请检查一下是否有效。请注意，我还没有测试过代码。我在代码中添加了一些注释，以便您可以了解在哪里放置什么。
public class Reciepe extends AppCompatActivity {
String Barname;
String finalJson;
private ListView reciepeListView;
private ListAdapter adapter;
private ProgressDialog loading;
List<Listview_reciepe_conveyer> fixture_conveyerList;
String url = "http://thehostels.in/Foody/reciepe_json.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_reciepe);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Set up ListView.
reciepeListView = (ListView) findViewById(R.id.list_recipe);
fixture_conveyerList = new ArrayList<Listview_reciepe_conveyer>();
adapter = new ListAdapter(this, R.layout.list_item, fixture_conveyerList);
reciepeListView.setAdapter(adapter);
JSONTask();
toolbar.setBackgroundColor(Color.parseColor("#FFBC03"));
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
DisplayImageOptions options = new DisplayImageOptions.Builder()
.cacheInMemory(true)
.cacheOnDisk(true)
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(Reciepe.this)
.defaultDisplayImageOptions(options)
.build();
com.nostra13.universalimageloader.core.ImageLoader.getInstance().init(config);
Intent intent = getIntent();
if (intent != null) {
Barname = intent.getStringExtra("Type");
Log.e("Type", Barname);
}
if (Barname != null) {
switch (Barname) {
case "Punjabi":
getSupportActionBar().setTitle("Punjabi");
break;
case "Chinese":
getSupportActionBar().setTitle("Chinese");
break;
case "South Indian":
getSupportActionBar().setTitle("South Indian");
break;
case "Gujarati":
getSupportActionBar().setTitle("Gujarati");
break;
case "Chicken":
getSupportActionBar().setTitle("Chicken");
break;
}
}
}
public void JSONTask() {
ProgressDialog loading;
RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
StringRequest sr = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
Log.e("response : ", response);
JSONObject parentObject = null;
try {
parentObject = new JSONObject(response);
} catch (JSONException e) {
e.printStackTrace();
}
JSONArray parentArray = null;
try {
assert parentObject != null;
parentArray = parentObject.getJSONArray("list");
} catch (JSONException e) {
e.printStackTrace();
}
assert parentArray != null;
for (int i = 0; i < parentArray.length(); i++) {
JSONObject finalObject = null;
try {
finalObject = parentArray.getJSONObject(i);
} catch (JSONException e) {
e.printStackTrace();
}
Listview_reciepe_conveyer fixtureList = new Listview_reciepe_conveyer();
try {
assert finalObject != null;
fixtureList.setImage(finalObject.getString("image"));
} catch (JSONException e) {
e.printStackTrace();
}
try {
fixtureList.setFood(finalObject.getString("food"));
} catch (JSONException e) {
e.printStackTrace();
}
try {
fixtureList.setPrice(finalObject.getString("price"));
} catch (JSONException e) {
e.printStackTrace();
}
fixture_conveyerList.add(fixtureList);
}
// Call notifyDataSetChanged here to make the ListView to update its data
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.e("response : ", error.toString());
}
}) {
@Override
protected Map<String, String> getParams() {
Map<String, String> params = new HashMap<String, String>();
params.put("Dish", Barname);
Log.d("Dish", ": " + params.toString());
return params;
}
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String, String> params = new HashMap<String, String>();
params.put("Content-Type", "application/x-www-form-urlencoded");
return params;
}
};
Log.d("Leaderboard", "Req : " + sr.getUrl());
requestQueue.add(sr);
}
}
这是适配器。
private class ListAdapter extends ArrayAdapter<Listview_reciepe_conveyer> {
private List<Listview_reciepe_conveyer> reciepe_conveyerList;
private int resource;
private LayoutInflater inflater;
public ListAdapter(Context context, int resource, List<Listview_reciepe_conveyer> objects) {
super(context, resource, objects);
reciepe_conveyerList = objects;
this.resource = resource;
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = inflater.inflate(resource, null);
}
ImageView food_photo;
final TextView food, price;
food_photo = (ImageView) convertView.findViewById(R.id.food_photo);
food = (TextView) convertView.findViewById(R.id.food_name);
price = (TextView) convertView.findViewById(R.id.food_price);
ImageLoader.getInstance().displayImage(reciepe_conveyerList.get(position).getImage(), food_photo);
food.setText(reciepe_conveyerList.get(position).getFood());
String newprice = ("Rs." + reciepe_conveyerList.get(position).getPrice());
price.setText(newprice);
return convertView;
}
}
和班级
public class Listview_reciepe_conveyer {
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String getFood() {
return food;
}
public void setFood(String food) {
this.food = food;
}
private String image;
private String food;
private String price;
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
}
布局list_item是要在ListView中显示为每个列表项的项目。