我是android新手，目前我想开发一个需要使用凌空请求网络的应用程序。但是，它会返回以下错误：
Caused by: java.lang.IllegalStateException: RequestQueue not initialized
at com.myapp.zeptomobile.myapp.app.StaggeredDemoApplication.getRequestQueue(StaggeredDemoApplication.java:35)
at com.myapp.zeptomobile.myapp.FlickrActivity.onCreate(FlickrActivity.java:75)
at android.app.Activity.performCreate(Activity.java:5248)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2164)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2249)
at android.app.ActivityThread.access$800(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1212)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5052)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)
01-18 14:07:15.655 24065-24065/com.myapp.zeptomobile.myapp I/Process: Sending signal. PID: 24065 SIG: 9
以下是主程序
enter public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, FragmentRecent.OnFragmentInteractionListener,
FragmentAseanGirl.OnFragmentInteractionListener,FragmentFlickrStart.OnFragmentInteractionListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (savedInstanceState == null) {
Fragment fragment = null;
Class fragmentClass = null;
fragmentClass = FragmentRecent.class;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
}
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
Fragment fragment = null;
Class fragmentClass = null;
if (id == R.id.nav_camera) {
fragmentClass = FragmentRecent.class;
} else if (id == R.id.nav_gallery) {
fragmentClass = FragmentAseanGirl.class;
} else if (id == R.id.nav_slideshow) {
fragmentClass = FragmentRecent.class;
} else if (id == R.id.nav_manage) {
fragmentClass = FragmentFlickrStart.class;
} else if (id == R.id.nav_share) {
fragmentClass = FragmentRecent.class;
} else if (id == R.id.nav_send) {
fragmentClass = FragmentAseanGirl.class;
}
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onFragmentInteraction(Uri uri) {
}
}
以下是片段计划
public class FragmentFlickrStart extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public FragmentFlickrStart() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment FragmentTwo.
*/
// TODO: Rename and change types and number of parameters
public static FragmentFlickrStart newInstance(String param1, String param2) {
FragmentFlickrStart fragment = new FragmentFlickrStart();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
Intent intent = new Intent(getActivity(),FlickrActivity.class);
startActivity(intent);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_flickrstart, container, false);
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
以下是活动计划
public class FlickrActivity extends Activity{
private StaggeredGridView mStaggeredView;
private RequestQueue mVolleyQueue;
private ProgressDialog mProgress;
private int currPage=1;
GsonRequest<FlickrResponsePhotos> gsonObjRequest;
private RelativeLayout mListFooter;
private boolean isLoading = false;
private final String TAG_REQUEST = "MY_TAG";
private StaggeredGridView.OnScrollListener scrollListener = new StaggeredGridView.OnScrollListener() {
public void onTop() {
}
public void onScroll() {
}
public void onBottom() {
loadMoreData();
}
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flickr);
//actionBarSetup();
// Initialise Volley Request Queue. added to fix TBS
if(mVolleyQueue==null){
mVolleyQueue= Volley.newRequestQueue(getApplicationContext());
}
mVolleyQueue = StaggeredDemoApplication.getRequestQueue();
mListFooter = (RelativeLayout) findViewById(R.id.footer);
mStaggeredView = (StaggeredGridView) findViewById(R.id.staggeredview);
// Be sure before calling initialize that you haven't initialised from XML
//mStaggeredView.initialize(2, StaggeredGridView.Mode.FIXED);
mStaggeredView.setOnScrollListener(scrollListener);
showProgress();
flickerGetImagesRequest();
}
public void onStop() {
super.onStop();
if(mProgress != null)
mProgress.dismiss();
}
private void loadMoreData() {
if ( isLoading )
return;
mListFooter.setVisibility(View.VISIBLE);
isLoading = true;
flickerGetImagesRequest();
}
private void flickerGetImagesRequest() {
String url = "https://api.flickr.com/services/rest";
Uri.Builder builder = Uri.parse(url).buildUpon();
builder.appendQueryParameter("api_key", "5e045abd4baba4bbcd866e1864ca9d7b");
//builder.appendQueryParameter("method", "flickr.interestingness.getList"); //TBS
builder.appendQueryParameter("method", "flickr.photos.search");
builder.appendQueryParameter("tags","bikinigirl,lingerine");
//builder.appendQueryParameter("sort","relevance");
builder.appendQueryParameter("format", "json");
builder.appendQueryParameter("nojsoncallback", "1");
builder.appendQueryParameter("per_page", "10");
builder.appendQueryParameter("page", Integer.toString(currPage));
gsonObjRequest = new GsonRequest<FlickrResponsePhotos>(Request.Method.GET, builder.toString(),
FlickrResponsePhotos.class, null, new Response.Listener<FlickrResponsePhotos>() {
@Override
public void onResponse(FlickrResponsePhotos response) {
try {
if(response != null) {
parseFlickrImageResponse(response);
currPage++;
}
} catch (Exception e) {
e.printStackTrace();
showToast("JSON parse error");
}
stopProgress();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// Handle your error types accordingly.For Timeout & No connection error, you can show 'retry' button.
// For AuthFailure, you can re login with user credentials.
// For ClientError, 400 & 401, Errors happening on client side when sending api request.
// In this case you can check how client is forming the api and debug accordingly.
// For ServerError 5xx, you can do retry or handle accordingly.
if( error instanceof NetworkError) {
} else if( error instanceof ClientError) {
} else if( error instanceof ServerError) {
} else if( error instanceof AuthFailureError) {
} else if( error instanceof ParseError) {
} else if( error instanceof NoConnectionError) {
} else if( error instanceof TimeoutError) {
}
//mStaggeredView.onRefreshComplete();
stopProgress();
showToast(error.getMessage());
}
});
gsonObjRequest.setTag(TAG_REQUEST);
mVolleyQueue.add(gsonObjRequest);
}
private void showProgress() {
mProgress = ProgressDialog.show(this, "", "Loading...");
}
private void stopProgress() {
isLoading = false;
mListFooter.setVisibility(View.GONE);
mProgress.cancel();
}
private void showToast(String msg) {
Toast.makeText(FlickrActivity.this, msg, Toast.LENGTH_LONG).show();
}
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
private void parseFlickrImageResponse(FlickrResponsePhotos response) {
FlickrGetImagesResponse photos = response.getPhotos(); //pass array of images to Picture Activity
String[] photoUrl;
photoUrl = new String[photos.getPhotos().size()];
for (int index = 0; index < photos.getPhotos().size(); index++) {
FlickrImage flkrImage = photos.getPhotos().get(index);
photoUrl[index]=flkrImage.getImageUrl();
StaggeredGridViewItem item = null;
item = new GridItem(this, flkrImage,photoUrl); //pass one image of index
mStaggeredView.addItem(item);
}
}
}
以下是队列请求程序
public class StaggeredDemoApplication extends Application {
private static Context applicationContext;
private static RequestQueue mRequestQueue;
private static ImageLoader mImageLoader;
private static BitmapLruCache mBitmapCache;
public static boolean INIT_FLAG = true;
public void onCreate() {
super.onCreate();
applicationContext = this.getApplicationContext();
mRequestQueue = Volley.newRequestQueue(applicationContext);
long size = Runtime.getRuntime().maxMemory()/4;
mBitmapCache = new BitmapLruCache(50);//(int)size);
mImageLoader = new ImageLoader(mRequestQueue, mBitmapCache);
}
public static RequestQueue getRequestQueue() {
if (mRequestQueue != null) {
return mRequestQueue;
} else {
throw new IllegalStateException("RequestQueue not initialized");
}
}
public static ImageLoader getImageLoader() {
if (mImageLoader != null) {
return mImageLoader;
} else {
throw new IllegalStateException("ImageLoader not initialized");
}
}
}
显示错误的行位于FlickrActivity.java
mVolleyQueue = StaggeredDemoApplication.getRequestQueue();
以下是我的清单文件
<?xml version="1.0" encoding="utf-8"?>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".FlickrActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name=".FullScreenImageActivity"
android:screenOrientation="portrait" />
</application>
请建议并帮助......谢谢你！
答案 0 :(得分：0)
在清单中注册应用程序类名，以避免请求未初始化问题
<application
android:name=".StaggeredDemoApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">