我有一个MainActivity，其中创建了Swipeable选项卡，并从那里调用了两个片段。我有2个片段A和片段B的web服务，我必须解析来自服务器的数据。我正在使用凌空抽射。当我在第一个片段;正在调用Web服务，并且第一次没有加载数据。
但是在第二次它正确显示但是它应该是这样的，当我在片段A中时应该调用片段A的服务，当我在片段B中时，应该调用片段B的服务。我正在附上代码片段。
MainActivity.java
public class MainActivity extends AppCompatActivity {
DrawerLayout mDrawerLayout;
NavigationView mNavigationView;
FragmentManager mFragmentManager;
FragmentTransaction mFragmentTransaction;
int status = 0 ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/**
*Setup the DrawerLayout and NavigationView
*/
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
mNavigationView = (NavigationView) findViewById(R.id.shitstuff);
android.support.v7.widget.Toolbar toolbar = (android.support.v7.widget.Toolbar) findViewById(R.id.toolbar);
// Show menu icon
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowHomeEnabled(true);
/**
* Lets inflate the very first fragment
* Here , we are inflating the NewsFragment as the first Fragment
*/
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.containerView, new NewsFragment()).commit();
// mNavigationView.setBackgroundColor(Color.parseColor("#CFCFCF"));
/**
* Setup click events on the Navigation View Items.
*/
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
mDrawerLayout.closeDrawers();
if (menuItem.getItemId() == R.id.nav_item_sent) {
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.containerView, new SportsFragment()).commit();
status = 1;
if (status == 1){
}
}
if (menuItem.getItemId() == R.id.nav_item_inbox) {
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new NewsFragment()).commit();
}
if (menuItem.getItemId() == R.id.nav_item_sent){
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new VideosFragment()).commit();
}
if (menuItem.getItemId() == R.id.nav_item_draft) {
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new OpinionFragment()).commit();
}
if (menuItem.getItemId() == R.id.nav_item_sports) {
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new SportsFragment()).commit();
}
if (menuItem.getItemId() == R.id.nav_item_weather) {
FragmentTransaction xfragmentTransaction = mFragmentManager.beginTransaction();
xfragmentTransaction.replace(R.id.containerView, new NewsFragment()).commit();
}
return false;
}
});
/**
* Setup Drawer Toggle of the Toolbar
*/
ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.app_name,
R.string.app_name);
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_about_us:
Intent intent = new Intent(MainActivity.this, AboutUs.class);
startActivity(intent);
return true;
case R.id.action_terms_of_use:
Intent intent_two = new Intent(MainActivity.this, TermsUse.class);
startActivity(intent_two);
return true;
case R.id.action_privacy_policy:
Intent intent_three = new Intent(MainActivity.this, PrivacyPolicy.class);
startActivity(intent_three);
return true;
case R.id.action_contact_us:
Intent intent_four = new Intent(MainActivity.this, ContactUs.class);
startActivity(intent_four);
case R.id.search:
// hidetext();
Toast.makeText(MainActivity.this, "In the development Phase... Thank You...", Toast.LENGTH_SHORT).show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
// private void hidetext() {
//
// Intent i = new Intent(MainActivity.this, SearchResultActivity.class);
// startActivity(i);
// }
}
TopNewsFragment
public class TopNewsFragment extends Fragment {
// Log tag
private static final String TAG = MainActivity.class.getSimpleName();
private static final String url = "http://sikkimexpress.itstunner.com/api/homenewslist/topnews";
private ProgressDialog pDialog;
private List<Movie> movieList = new ArrayList<Movie>();
Movie movie;
private ListView listView;
private CustomListAdapter adapter;
String imageURL = "", title = "", description = "";
public static final String KEY_ID = "news_id";
public static final String KEY_HEADURL = "news_url";
public static final String KEY_DETAILS = "news_details";
public static final String KEY_TITLE = "news_title";
RequestQueue requestQueue;
public TopNewsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.fragment_news, container, false);
listView = (ListView) rootView.findViewById(R.id.list);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int Position,
long offset) {
// TODO Auto-generated method stub
Movie item = (Movie) adapter.getItem(Position);
Intent intent = new Intent(rootView.getContext(), DetailsPage.class);
intent.putExtra(KEY_ID, item.getNewsId());
intent.putExtra(KEY_HEADURL, item.getThumbnailUrl());
intent.putExtra(KEY_TITLE, item.getTitle());
intent.putExtra(KEY_DETAILS, item.getDescription());
startActivity(intent);
}
});
// requestQueue = Volley.newRequestQueue(getActivity());
adapter = new CustomListAdapter(getActivity(), movieList);
listView.setAdapter(adapter);
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Loading...Please Wait...");
pDialog.setCancelable(false);
pDialog.show();
Volley.newRequestQueue(getActivity()).add(new JsonObjectRequest(Request.Method.GET, url, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
hidePDialog();
try {
JSONArray jsonArray = response.getJSONArray("HomeNews");
// if (jsonArray.length() == 0) {
// new AlertDialog.Builder(getActivity())
// .setTitle("Alert")
// .setMessage("No Items found...")
// .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // continue with delete
// }
// })
// .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // do nothing
// }
// })
// .setIcon(android.R.drawable.ic_dialog_alert)
// .show();
// }
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject homenews = jsonArray.getJSONObject(i);
Movie movie = new Movie();
movie.setNewsId(homenews.getString("NewsId"));
movie.setDateTime(homenews.getString("DateTime"));
movie.setNewsType(homenews.getString("NewsType"));
movie.setTitle(homenews.getString("Title"));
title = movie.setTitle(homenews.getString("Title"));
description = movie.setDescription(homenews.getString("Description"));
movie.setDescription(homenews.getString("Description"));
imageURL = movie.setThumbnailUrl(homenews.getString("MainImageThumbnail"));
movie.setThumbnailUrl(homenews.getString("MainImageThumbnail"));
movieList.add(movie);
System.out.println("Setting up in ListView");
// System.out.println("Result:- " + newsId + " " + dateTime + " " + newsType + " " + title + " " + description + " " + mainImageURL);
}
} catch (JSONException e) {
e.printStackTrace();
}
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// new AlertDialog.Builder(getActivity())
// .setTitle("No Connectivity ")
// .setMessage("Please check your internet connectivity!")
// .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // continue with delete
// }
// })
// //.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
// //public void onClick(DialogInterface dialog, int which) {
// // do nothing
// //}
// //})
// .setIcon(android.R.drawable.ic_dialog_alert)
// .show();
hidePDialog();
}
}));
// AppController.getInstance().addToRequestQueue(jsonObjectRequest);
// requestQueue.add(jsonObjectRequest);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
@Override
public void onDetach() {
super.onDetach();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
}
LatestNewsFragment.java
public class LatestNewsFragment extends Fragment {
// Log tag
private static final String TAG = MainActivity.class.getSimpleName();
private static final String url = "http://sikkimexpress.itstunner.com/api/homenewslist/latest";
private ProgressDialog pDialog;
private List<Movie> movieList = new ArrayList<Movie>();
private ListView listView;
private CustomListAdapter adapter;
// contacts JSONArray
private JSONArray users = null;
RequestQueue requestQueue;
public static final String KEY_HEADURL="news_url";
public static final String KEY_DETAILS="news_details";
public static final String KEY_TITLE = "news_title";
public LatestNewsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.fragment_news, container, false);
listView = (ListView) rootView.findViewById(R.id.list);
// requestQueue = Volley.newRequestQueue(getActivity());
adapter = new CustomListAdapter(getActivity(), movieList);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int Position,
long offset) {
// TODO Auto-generated method stub
Movie item = (Movie) adapter.getItem(Position);
Intent intent = new Intent(rootView.getContext(), DetailsPage.class);
// intent.putExtra("URL", movie.getThumbnailUrl());
// intent.putExtra("title", movie.getTitle());
// intent.putExtra("description", movie.getDescription());
intent.putExtra(KEY_HEADURL, item.getThumbnailUrl());
intent.putExtra(KEY_TITLE, item.getTitle());
intent.putExtra(KEY_DETAILS, item.getDescription());
startActivity(intent);
}
});
pDialog = new ProgressDialog(getActivity());
// Showing progress dialog before making http request
pDialog.setMessage("Loading...Please Wait...");
pDialog.setCancelable(false);
pDialog.show();
Volley.newRequestQueue(getActivity()).add(new JsonObjectRequest(Request.Method.GET, url, new Response.Listener<JSONObject>() {
// JsonObjectRequest jsonObjectRequest =
@Override
public void onResponse(JSONObject response) {
try {
hidePDialog();
JSONArray jsonArray = response.getJSONArray("HomeNews");
// if (jsonArray.length() == 0){
// new AlertDialog.Builder(getActivity())
// .setTitle("Alert")
// .setMessage("No Items found...")
// .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // continue with delete
// }
// })
// .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // do nothing
// }
// })
// .setIcon(android.R.drawable.ic_dialog_alert)
// .show();
// }
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject homenews = jsonArray.getJSONObject(i);
Movie movie = new Movie();
movie.setNewsId(homenews.getString("NewsId"));
movie.setDateTime(homenews.getString("DateTime"));
movie.setNewsType(homenews.getString("NewsType"));
movie.setTitle(homenews.getString("Title"));
movie.setDescription(homenews.getString("Description"));
movie.setThumbnailUrl(homenews.getString("MainImageThumbnail"));
movieList.add(movie);
System.out.println("Setting up in ListView");
}
} catch (JSONException e) {
e.printStackTrace();
}
adapter.notifyDataSetChanged();
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// new AlertDialog.Builder(getActivity())
// .setTitle("No Connectivity ")
// .setMessage("Please check your internet connectivity!")
// .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
// public void onClick(DialogInterface dialog, int which) {
// // continue with delete
// }
// })
// //.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
// //public void onClick(DialogInterface dialog, int which) {
// // do nothing
// //}
// //})
// .setIcon(android.R.drawable.ic_dialog_alert)
// .show();
hidePDialog();
}
}));
// AppController.getInstance().addToRequestQueue(jsonObjectRequest);
// requestQueue.add(jsonObjectRequest);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
@Override
public void onDetach() {
super.onDetach();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
}
答案 0 :(得分：1)
可能发生的是，即使您一次只查看一个片段，这两个片段都会被加载。而不是在每个请求上创建一个新的RequestQueue，你应该只有一个。例如，像这样创建一个Application类：
public class MyApp extends Application {
private RequestQueue mRequestQueue;
private static MyApp mInstance;
@Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized MyApp getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
}
不要忘记将您的应用程序类添加到<activity>标记内的清单中：
<application
android:name=".MyApp"
现在，您可以从片段中对该队列发出请求：
JsonObjectRequest req = new JsonObjectRequest(Request.Method.GET,
URL, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
//Do something with response
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
//Do something with error
}
});
//Put the actual request on the queue
MyApp.getInstance().addToRequestQueue(req);