当我在＜code＞TabLayout＜/code＞片段中“快速”时，“atempt to invoke virtual method”＜code＞Android.content.res.Resources Android.contet.Context。getResources（）处理Null对象引用错误。
我的代码 ：
public class MangaMenuPage extends Fragment implements Response.ErrorListener, ConnectionReceiver.ConnectivityReceiverListener, View.OnClickListener {
public String getTitle(){
return "MENÜ";
}
View v;
LinearLayout lnrlayout;
String URL_getCategory, URL_getProductToCategory, URL_getFiveteenChapters;
ProgressBar progressBar;
List<String> lstheaders;
RecMangaListAdapter recMangaListAdapter;
List<Products> lstProduct;
Category category;
Products products;
int categorySize;
View screen_connectionError;
Chapters chapters;
FrameLayout frm;
MySingleton mySingleton;
RequestQueue requestQeueu;
StringRequest getCategory, getFiveTeenChapter, getProductToCategory;
HashMap<Integer, String> lstCategory = new HashMap<>();
int top = 15;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
v = inflater.inflate(R.layout.fragment_manga_menu_page, container, false);
initStep1(v);
return v;
}
void receiverSettings() {
BroadcastReceiver conn = new ConnectionReceiver();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(CONNECTIVITY_ACTION);
getContext().registerReceiver(conn, intentFilter);
}
private void initStep1(View v) {
progressBar = v.findViewById(R.id.fragment_menuPage_progressBar);
screen_connectionError = v.findViewById(R.id.lnr);
FloatingActionButton fab = v.findViewById(R.id.fab_checkInternet);
fab.setOnClickListener(this);
ConnectionReceiver.connectionInfo = this;
lnrlayout = v.findViewById(R.id.lnrlyt_manga_menu_page);
lnrlayout.setOrientation(LinearLayout.VERTICAL);
lstProduct = new ArrayList<>();
lstheaders = new ArrayList<>();
requestQeueu = Volley.newRequestQueue(getContext());
receiverSettings();
}
void requestAdd(StringRequest request, String _tag) {
request.setTag(_tag);
requestQeueu.add(request);
}
void ApiPull() {
lstProduct.clear();
lnrlayout.removeAllViews();
lstheaders.add(getString(R.string.oneSegmentName));
URL_getFiveteenChapters = getString(R.string.URL_getChapters);
getFiveTeenChapter = new StringRequest(Request.Method.GET, URL_getFiveteenChapters, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
chapters = gson.fromJson(response, Chapters.class);
List<Chapters> lstChapters = new ArrayList<>();
lstChapters.add(chapters);
useApi(lstChapters, lstheaders.get(0));
categoryApiPull();
}
}, this);
requestAdd(getFiveTeenChapter, "getFiveTeenChapter");
}
void categoryApiPull() {
URL_getCategory = getString(R.string.URL_getCategory);
getCategory = new StringRequest(Request.Method.GET, URL_getCategory, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
category = gson.fromJson(response, Category.class);
categorySize = category.getGetCategoryListResult().size();
int id;
for (int i = 0; categorySize > i; i++) {
id = category.getGetCategoryListResult().get(i).getCategoryID();
lstheaders.add(category.getGetCategoryListResult().get(i).getCategoryName());
lstCategory.put(category.getGetCategoryListResult().get(i).getCategoryID(),
category.getGetCategoryListResult().get(i).getCategoryName());
URL_getProductToCategory = getString(R.string.URL_getProductToCategory) + id;
getProductToCategory = new StringRequest(Request.Method.GET, URL_getProductToCategory, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
GsonBuilder gsonBuilder = new GsonBuilder();
Gson gson = gsonBuilder.create();
products = gson.fromJson(response, Products.class);
if (products.getGetProductListResult().size() != 0) {
useApiOther(lstCategory.get(products.getGetProductListResult().get(0).getCategoryID()), products);
}
new CountDownTimer(1000, 1000) {
@Override
public void onTick(long l) {
}
@Override
public void onFinish() {
progressState(View.INVISIBLE);
if (lnrlayout.getVisibility() == View.INVISIBLE) {
lnrlayout.setVisibility(View.VISIBLE);
}
}
}.start();
}
}, MangaMenuPage.this);
requestAdd(getProductToCategory, "getProductToCategory");
}
}
}, MangaMenuPage.this);
requestAdd(getCategory, "getCategory");
}
void progressState(int state) {
progressBar.setVisibility(state);
}
@Override
public void onErrorResponse(VolleyError error) {
progressState(View.INVISIBLE);
if (error.networkResponse == null) {
if (error.getClass().equals(TimeoutError.class)) {
// Show timeout error message
Toast.makeText(getContext(),
"Oops. Timeout error!",
Toast.LENGTH_LONG).show();
} else if (error.getClass().equals(NoConnectionError.class)) {
// Show timeout error message
Toast.makeText(getContext(),
"Oops. Connection error!",
Toast.LENGTH_LONG).show();
}
} else {
Toast.makeText(getContext(), "Hata => " + MessagePackage.getErrorMessage(error, getContext()), Toast.LENGTH_SHORT).show();
}
}
private void useApiOther(String categoryName, Products _lstProduct) {
recMangaListAdapter = new RecMangaListAdapter(_lstProduct, getContext());
CardOlustur(categoryName);
}
private void useApi(List<Chapters> lstChapters, String categoryName) {
recMangaListAdapter = new RecMangaListAdapter(getContext(), lstChapters);
CardOlustur(categoryName);
}
private TextView TxtOlustur(String text) {
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(15, 10, 0, 10);
TextView txtView = new TextView(getContext());
txtView.setText(text);
txtView.setTextSize(18.0f);
txtView.setGravity(Gravity.LEFT);
txtView.setTextColor(getResources().getColor(R.color.colorText));
txtView.setText(text);
txtView.setLayoutParams(layoutParams);
return txtView;
}
private RecyclerView RecOlustur() {
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());
linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
RecyclerView recyclerView = new RecyclerView(getContext());
recyclerView.setLayoutParams(layoutParams);
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(recMangaListAdapter);
return recyclerView;
}
private void CardOlustur(String txt) {
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(15, top, 15, 15);
top = 0;
CardView cardView = new CardView(getContext());
cardView.setLayoutParams(layoutParams);
cardView.setRadius(5f);
cardView.setMaxCardElevation(5);
cardView.addView(LinearLayoutOlustur(TxtOlustur(txt), RecOlustur()));
lnrlayout.addView(cardView);
}
private LinearLayout LinearLayoutOlustur(TextView txt, RecyclerView recyclerView) {
LinearLayout linearLayout = new LinearLayout(getContext());
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
linearLayout.setLayoutParams(layoutParams);
linearLayout.setOrientation(LinearLayout.VERTICAL);
linearLayout.addView(txt);
linearLayout.addView(recyclerView);
return linearLayout;
}
@Override
public void onNetworkConnectionChangedd(boolean isConnected) {
if (!isConnected) {
screen_connectionError.setVisibility(View.VISIBLE);
Toast.makeText(getContext(), "İnternet Bağlantınızı Kontrol Ediniz.", Toast.LENGTH_SHORT).show();
} else if (isConnected) {
lnrlayout.removeView(screen_connectionError);
ApiPull();
}
}
@Override
public void onClick(View v) {
ConnectivityManager conManager = (ConnectivityManager) getContext().getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = conManager.getActiveNetworkInfo();
boolean isConnection = networkInfo != null && networkInfo.isConnected();
onNetworkConnectionChangedd(isConnection);
}
}
错误：
2019-05-10 15:15:44.806 1314-1314/com.yuhdeveloper.manga E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.yuhdeveloper.manga, PID: 1314
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
at android.view.ViewConfiguration.get(ViewConfiguration.java:469)
at android.view.View.<init>(View.java:4867)
at android.view.View.<init>(View.java:5054)
at android.view.ViewGroup.<init>(ViewGroup.java:597)
at android.widget.FrameLayout.<init>(FrameLayout.java:92)
at android.widget.FrameLayout.<init>(FrameLayout.java:87)
at android.support.v7.widget.CardView.<init>(CardView.java:121)
at android.support.v7.widget.CardView.<init>(CardView.java:117)
at android.support.v7.widget.CardView.<init>(CardView.java:113)
at com.yuhdeveloper.mangaship.Fragments.MangaMenuPage.CardOlustur(MangaMenuPage.java:289)
at com.yuhdeveloper.mangaship.Fragments.MangaMenuPage.useApiOther(MangaMenuPage.java:247)
at com.yuhdeveloper.mangaship.Fragments.MangaMenuPage.access$100(MangaMenuPage.java:50)
at com.yuhdeveloper.mangaship.Fragments.MangaMenuPage$2$1.onResponse(MangaMenuPage.java:186)
at com.yuhdeveloper.mangaship.Fragments.MangaMenuPage$2$1.onResponse(MangaMenuPage.java:178)
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:78)
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:106)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:7000)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)
避免获取空上下文实例的常见做法，它可能会内存泄漏。其他使用静态应用程序实例，如MyApplication.getInstance（）
