Currently I'm coding an android project using Android Studio 3.1.2 and SDK 19.
When I refactored almost my whole code and replaced a lot of getContext() calls with requireContext() and getActivity() with requireActivity() i came across the problem, that the app crashes already at the launcher activity. I know that there are several posts related to the same problem of getting IllegalStateException: Fragment myFragment not attached to a contextbut they're all very project-specific so it doesn't actually show me the step i missed to do. So i hereby show you my example of code and pray for a merciful programmer that enlightens me, what I have to do, to solve this problem just in the suiting way.
This is my SplashActivity (the launcher activity):
public class SplashActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
Fragment fragmentToDisplay = null;
if (!(getIntent().getBooleanExtra("isLaunch", true))) {
fragmentToDisplay = new LoginFragment();
} else {
if (savedInstanceState == null) {
fragmentToDisplay = new SplashFragment();
}
}
if (fragmentToDisplay.isAdded()) {
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, fragmentToDisplay).commit();
}
}
}
This is the SplashFragment which gets loaded initially:
public class SplashFragment extends RequestingFragment {
private Handler delayHandler = new Handler();
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View fragmentView = inflater.inflate(R.layout.fragment_splash, container, false);
requestQueue = Volley.newRequestQueue(this.requireContext());
requestParams.add(SessionHandler.getAppInstanceID(this.getContext()));
startRequest(RequestOperation.SESSION_CHECK);
onSuccess(new JSONObject(), "");
return fragmentView;
}
#Override
public void onDestroy() {
super.onDestroy();
delayHandler.removeCallbacksAndMessages(null);
}
#Override
public void onSuccess(final JSONObject json, String parsingKey) {
delayHandler.postDelayed(new Runnable() {
#Override
public void run() {
//parsing stuff
}
}, 2000);
}
#Override
public void onError() {
showErrorDialog();
}
private void showErrorDialog() {
//show a horrifying dialog
}
}
I would be very thankful, if someone could explain to me, what in particular is causing the exception and how do I do it correctly. Thanks in advance.
Related
I'm new in android. I have a code which is consisted ViewPager and TabLayout. And it has 4 Fragments. On my Fragment4 code, I want to use CircleProgressView which I got in GitHub. To use that code, I should use AsyncTask. And it has "MainActivity.this.runOnUiThread(new Runnable){}". But this code occurred error. The message is "MainActivity is not an enclosing class." I think it means MainActivity class could not be referred. How can I call "MainActivity.this.runOnUiThread()"? Please tell me how to fix code.
Here is a part of my code.
public class Fragment4 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment4, container, false);
...
return rootView;
}
#Override
public void onStart() {
super.onStart();
}
private class LongOperation extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
mCircleView.setValue(0);
mCircleView.spin();
}
});
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
mCircleView.setValueAnimated(42);
}
}
}
MainActivity.this is just a way to get the Activity context, however there are multiple other ways to obtain this context.
Use getActivity() to get the context from the current Activity
Use getApplicationContext(), which is a different context which is the same for all activities but should work here too.
If you use API 23 or above you can use getContext() from within a Fragment to get the current context.
Use getActivity() instead of MainActivity.this
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
mCircleView.setValue(0);
mCircleView.spin();
}
});
Below is the MainActivity class that I'm using. The code checks to see if the phone is in landscape or portrait. If it's in portrait, it will show the main fragment in the main activity only (the main fragment is a static fragment in the main_activity.xml file). Then if a "Recipe" is clicked it will open a detail activity with its own fragment. If the phone is in landscape mode, it will show the main fragment and the detail fragment side by side. Everything works perfectly fine however when I follow the procedure below I get a white screen instead of the main activity:
Procedure:
Switch to landscape
Switch back to portrait
Choose an item and wait for the detail activity to open
Press back
Here instead of the main activity window I get a white screen
If I don't switch to landscape and just start with the portrait mode everything is fine. It seems like switching to landscape does something that causes the problem and I can't figure out what. Any tip on what's going on or where to look would be much appreciated.
public class MainActivity extends AppCompatActivity implements RecipesFragment.OnRecipeClickListener {
private String RECIPE_PARCEL_KEY;
private boolean mTwoPane;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RECIPE_PARCEL_KEY = getString(R.string.ParcelKey_RecipeParcel);
if (findViewById(R.id.linearLayoutTwoPane) != null) {
mTwoPane = true;
if (savedInstanceState == null) {
RecipeFragment recipeFragment = new RecipeFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.add(R.id.recipeFrameForTwoPane, recipeFragment)
.commit();
}
} else {
mTwoPane = false;
}
}
#Override
public void OnRecipeClick(Recipe recipe) {
if (mTwoPane) {
RecipeFragment recipeFragment = new RecipeFragment();
recipeFragment.setRecipe(recipe);
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.recipeFrameForTwoPane, recipeFragment)
.commit();
} else {
Class destinationClass = DetailActivity.class;
Intent intentToStartDetailActivity = new Intent(this, destinationClass);
intentToStartDetailActivity.putExtra(RECIPE_PARCEL_KEY, recipe);
startActivity(intentToStartDetailActivity);
}
}
}
EDIT:
Adding RecipeFragment's code below:
public class RecipeFragment extends Fragment {
private Recipe mRecipe;
#BindView(R.id.tv_recipeName) TextView recipeNameTextView;
public RecipeFragment(){
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.recipe_fragment,container,false);
ButterKnife.bind(this,view);
if(mRecipe!=null) {
recipeNameTextView.setText(mRecipe.getName());
}else{
recipeNameTextView.setText(getString(R.string.messageSelectARecipe));
}
return view;
}
public void setRecipe(Recipe recipe){
mRecipe = recipe;
}
}
EDIT:
I followed #mt0s's advice and created different background colors for the fragments and activities and finally narrowed down the problem to a line in my recyclerview adapter code. My adapter code is below. Inside loadInBackground() on line URL url = new URL(getString(R.string.URL_RecipeJSON)); I get a Fragment RecipesFragment{96e9b6a} not attached to Activity exception. I don't understand why I'm getting this exception and what the best way to resolve this is. Have I placed the right code in the right fragment methods (ie OnCreate vs OnActivityCreated vs OnCreateView vs etc)?
public class RecipesFragment extends Fragment
implements RecipeAdapter.RecipeAdapterOnClickHandler,
LoaderManager.LoaderCallbacks<ArrayList<Recipe>> {
#BindView(R.id.rv_recipes) RecyclerView mRecyclerView;
private RecipeAdapter mRecipeAdapter;
private static final int LOADER_ID = 1000;
private static final String TAG = "RecipesFragment";
private OnRecipeClickListener mOnRecipeClickListener;
public RecipesFragment(){
}
public interface OnRecipeClickListener {
void OnRecipeClick(Recipe recipe);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.recipes_fragment, container, false);
ButterKnife.bind(this, view);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.setHasFixedSize(true);
mRecipeAdapter = new RecipeAdapter(this);
mRecyclerView.setAdapter(mRecipeAdapter);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getLoaderManager().initLoader(LOADER_ID, null, this);
}
#Override
public void onPause() {
super.onPause();
}
#Override
public void onResume() {
super.onResume();
}
#Override
public void OnClick(Recipe recipe) {
mOnRecipeClickListener.OnRecipeClick(recipe);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
try{
mOnRecipeClickListener = (OnRecipeClickListener) context;
} catch (ClassCastException e){
Log.e(TAG, "onAttach: Host activity class must implement OnRecipeClickListener.");
}
}
#Override
public Loader<ArrayList<Recipe>> onCreateLoader(int i, Bundle bundle) {
return new AsyncTaskLoader<ArrayList<Recipe>>(getActivity()) {
#Override
protected void onStartLoading() {
super.onStartLoading();
forceLoad();
}
#Override
public ArrayList<Recipe> loadInBackground() {
String response;
ArrayList<Recipe> recipes = null;
try {
URL url = new URL(getString(R.string.URL_RecipeJSON)); //***I get an exception here***
response = NetworkUtils.getResponseFromHttpUrl(url, getActivity());
recipes = RecipeJsonUtils.getRecipeFromJson(getActivity(), response);
} catch (Exception e) {
Log.e(TAG, "loadInBackground: " + e.getMessage());
}
return recipes;
}
};
}
#Override
public void onLoadFinished(Loader<ArrayList<Recipe>> loader, ArrayList<Recipe> recipes) {
mRecipeAdapter.setRecipeData(recipes);
}
#Override
public void onLoaderReset(Loader<ArrayList<Recipe>> loader) {
}
}
I finally figured out the problem and the solution. The problem is that onStartLoading() in the AsyncTaskLoader anonymous class in RecipesFragment class gets called every time the fragment is resumed whether the enclosing Loader is called or not. This causes the problem. I need to have control over when onStartLoading() is being called and I only want it to be called if and only if the enclosing Loader is being initialized or restarted. As such, I destroyed the loader in onPause() of the fragment and restarted it in onResume(). Hence, I added the following code to the RecipesFragment class:
#Override
public void onPause() {
super.onPause();
getLoaderManager().destroyLoader(LOADER_ID);
}
#Override
public void onResume() {
super.onResume();
getLoaderManager().restartLoader(LOADER_ID, null, this);
}
I also removed initLoader() from onCreate(). This way, every time the fragment is resumed (or created) onStartLoading() will be called. I tried this and it solves my problem.
When you switch from the landscape to portrait or the opposite the Android OS destroy your activity and recreate it again. this what probably trigger your problem
First of all, I have 2 fragments and they show different json values(2 links). If I change fragment(.replace()), that fragment get values with retrofit and show it. It works well but other fragment is deleted with values. After change fragment, it downloads again so I change structure. I want to take 2 json objects once so I get json objects in mainactivity and fragments get these with methods. They work well in first opening but if i open a fragment second time, it gives this error. How can I solve it?
java.lang.IllegalStateException: Already executed.
at retrofit2.OkHttpCall.enqueue(OkHttpCall.java:84)
Code is very long, i will show main structure.
MainActivity.java
public class MainActivity extends AppCompatActivity
{
private Call<Restaurant[]> restaurantCall;
private Call<Dining[]> diningCall;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Restaurant Json value
RestaurantInterface restaurantInterface = RetroClient.getClient().create(RestaurantInterface.class);
restaurantCall = restaurantInterface.getJsonValues();
//Dininghall Json value
DiningInterface diningInterface = RetroClient.getClient().create(DiningInterface.class);
diningCall = diningInterface.getJsonValues();
}
public Call<Restaurant[]> RestaurantJson()
{
return this.restaurantCall;
}
public Call<Dining[]> DiningJson()
{
return this.diningCall;
}
}
RestaurantFragment.java (Other fragment has same structure)
public class RestFragment extends Fragment
{
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.fragment_rest, container, false);
Call<Restaurant[]> call = ((MainActivity) getActivity()).RestaurantJson();
call.enqueue(new Callback<Restaurant[]>()
{
.
.
Summing up, in order to avoid the "Already executed" exception, clone the call:
public Call<Restaurant[]> RestaurantJson()
{
return this.restaurantCall.clone();
}
public Call<Dining[]> DiningJson()
{
return this.diningCall.clone();
}
If you want to execute the call in the activity and not in the fragment as you are actually doing, then you need to call enqueue(new Callbak(... in your activity.
So you need something like this:
public class RestFragment extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_rest, container, false);
((MainActivity) getActivity()).RestaurantJson(this);
}
public void onResponse(Response<T> response) {
//your fragment code on response
}
...
}
public class MainActivity extends AppCompatActivity {
public void RestaurantJson(final RestFragment fragment)
{
RestaurantInterface restaurantInterface = RetroClient.getClient().create(RestaurantInterface.class);
restaurantCall = restaurantInterface.getJsonValues();
restaurantCall.enqueue(new Callback<Restaurant[]>() {
#Override
public void onResponse(Call<T> call, Response<T> response) {
...
fragment.onResponse(response);
}
}
...
}
The same for your DiningFragment and your dining call...
I have a SignupActivity which will go through several fragments as users go through a signup process. On the last fragment, I'm calling
getActivity().setResult(Activity.RESULT_OK)
since SingupActivity intent was started for result. Some users are crashing at this point, because getActivity() is producing a NPE. I'm not able to figure out what is causing this. Screen rotation is disabled, so there is no reason that I know of for the fragment to detach from the Activity.
Any insight as to what may be causing this, and how I can resolve it?
public class SignupConfirmationFragment extends Fragment {
public static final String TAG = SignupConfirmationFragment.class.getSimpleName();
private User mNewUser;
private myAppClient mmyAppClient;
private Animation rotateAnimation;
private ImageView avatar;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mNewUser = ((SignUpActivity) getActivity()).getNewUser();
mmyAppClient = ((SignUpActivity) getActivity()).getmyAppClient();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View v = inflater.inflate(R.layout.fragment_signup_confirmation, null);
((TextView) v.findViewById(R.id.username_textView)).setText(((SignUpActivity) getActivity()).getNewUser().getName());
avatar = (ImageView) v.findViewById(R.id.avatar);
if (mNewUser.getAvatarImage() != null) {
avatar.setImageBitmap(mNewUser.getAvatarImage());
}
rotateAnimation = AnimationUtils.loadAnimation(getActivity(), R.anim.progress_rotate);
v.findViewById(R.id.progress_loading).startAnimation(rotateAnimation);
if (mNewUser.getAvatarImage() != null) {
startAvatarUpload();
} else if (mNewUser.getNewsletter()) {
setNewsletterStatus();
} else {
pauseForOneSecond();
}
return v;
}
private void startAvatarUpload() {
mmyAppClient.uploadUserAvatar(mNewUser.getAvatarImage(), new FutureCallback<JsonObject>() {
#Override
public void onCompleted(Exception e, JsonObject result) {
if (mNewUser.getNewsletter()) {
setNewsletterStatus();
} else {
updateFragment();
}
}
},
null,
null);
}
private void setNewsletterStatus() {
mmyAppClient.setNewsletter(mNewUser.getEmail(), mNewUser.getFirstName(), mNewUser.getLastName(), new FutureCallback<String>() {
#Override
public void onCompleted(Exception e, String result) {
//Log.d(TAG, "Result: " + result);
updateFragment();
}
});
}
private void pauseForOneSecond() {
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
updateFragment();
}
}, 1000);
}
private void updateFragment() {
rotateAnimation.cancel();
if (isAdded()) {
getActivity().setResult(Activity.RESULT_OK);
AnalyticsManager.logUIEvent("sign up completed");
getActivity().finish();
} else {
AnalyticsManager.logUIEvent("sign up failed");
}
}
}
According to Fragment lifecycle in Android OS, you cannot get the Activity associated with the fragment in the onCreateView, because the Activity with which the Fragment is associated will not be created at that stage.
See the figure below:
Also, refer to this link, http://developer.android.com/guide/components/fragments.html
As you can see the Activity is created in onActivityCreated which is after onCreateView, hence you'll get null if you try to call the Activity in the onCreateView. Try to call it in onActivityCreated or in onStart that should solve your problem.
I hope this helps.
I am building an Android Application (minimum SDK Level 10). When the app is minimized and the user return later to it, the main menu shows buttons and images twice. It only happens when the user uses other apps in the middle, if it happens immediately then the menu is displayed correctly.
Here is the code of the fragment:
public class MainMenuFragment extends Fragment implements OnClickListener {
String mGreeting = "Hello, anonymous user (not signed in)";
public interface Listener {
public void onStartGameRequested(boolean hardMode);
public void onShowAchievementsRequested();
public void onShowLeaderboardsRequested();
public void onSignInButtonClicked();
public void onSignOutButtonClicked();
public void onPlayClicked();
public void onScoreClicked();
public void onFeedbackClicked();
}
Listener mListener = null;
boolean mShowSignIn = true;
View v;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(v==null){
v = inflater.inflate(R.layout.fragment_mainmenu, container, false);
final int[] CLICKABLES = new int[] {
R.id.show_leaderboards_button,
R.id.sign_in_button, R.id.sign_out_button, R.id.button_play, R.id.feedback
};
for (int i : CLICKABLES) {
v.findViewById(i).setOnClickListener(this);
}
}
else {
((ViewGroup)v.getParent()).removeView(v);
}
return v;
}
public void setListener(Listener l) {
mListener = l;
}
#Override
public void onStart() {
super.onStart();
//updateUi();
}
#Override
public void onResume() {
super.onResume();
updateUi();
}
#Override
public void onStop() {
super.onStop();
}
public void setGreeting(String greeting) {
mGreeting = greeting;
//updateUi();
}
void updateUi() {
try{
if (getActivity() == null) return;
getActivity().findViewById(R.id.sign_in_button).setVisibility(mShowSignIn ?
View.VISIBLE : View.GONE);
getActivity().findViewById(R.id.sign_out_button).setVisibility(mShowSignIn ?
View.GONE : View.VISIBLE);
}catch(Exception e){}
}
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.show_leaderboards_button:
mListener.onShowLeaderboardsRequested();
break;
case R.id.sign_in_button:
mListener.onSignInButtonClicked();
break;
case R.id.sign_out_button:
mListener.onSignOutButtonClicked();
break;
case R.id.feedback:
mListener.onFeedbackClicked();
break;
case R.id.button_play:
mListener.onPlayClicked();
break;
}
}
public void setShowSignInButton(boolean showSignIn) {
mShowSignIn = showSignIn;
updateUi();
}
}
Thank you in advance for any help. I cannot see what is called twice, and I have spent more hours than I would to admit.
EDIT 1: Trying Clint Deygoo solution. Defining View v inside the onCreate is not working neither. This is how I did it:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_mainmenu, container, false);
final int[] CLICKABLES = new int[] {
R.id.show_leaderboards_button,
R.id.sign_in_button, R.id.sign_out_button, R.id.button_play, R.id.feedback
};
for (int i : CLICKABLES) {
v.findViewById(i).setOnClickListener(this);
}
return v;
}
EDIT 2: SOLVED ISSUE. I removed updateUi() and it stopped happening. I am not sure about why it's working, but it is. Thank you all!
The problem is not in your onCreateView (You should use EDIT 1). It's about nested Fragments.
Raneez Ahmed posted a good answer here
Fragments within Fragments