By Why savedInstanceState is null?
But in onCreate method, SavedInstanceState is always null. you need to call super. onSaveInstanceState(savedInstanceState) before adding your values to the Bundle, or they will get wiped out on that call (Droid X Android 2.2).
Why savedInstanceState is null in android?
If there is no available instance data, the savedInstanceState will be null . Because the onCreate() method is called whether the system is creating a new instance of your activity or recreating a previous one, you must check whether the state Bundle is null before you attempt to read it.
How to save state of a Fragment?
Various Android system operations can affect the state of your fragment. To ensure the user’s state is saved, the Android framework automatically saves and restores the fragments and the back stack. Therefore, you need to ensure that any data in your fragment is saved and restored as well.
How to save whole Fragment state in android?
The first key is that we can save our Fragments’ state ourselves using FragmentManager. saveInstanceState(Fragment) . Before removing the Fragment, call this method to get a Bundle containing your Fragment’s saved state! The second key is restoring state.
What is savedInstanceState in Android?
The savedInstanceState is a reference to a Bundle object that is passed into the onCreate method of every Android Activity. Activities have the ability, under special circumstances, to restore themselves to a previous state using the data stored in this bundle.
How do I keep fragments alive?
If you want to keep your fragment running you can instead use FragmentManger hide() and show() methods! It hides and shows the fragments without destroying them. so first add both fragments to fragment manager and also hide the second fragment.
What is FragmentManager?
FragmentManager is the class responsible for performing actions on your app’s fragments, such as adding, removing, or replacing them, and adding them to the back stack.
How do I bypass savedInstanceState?
The savedInstanceState is a reference to a Bundle object that is passed into the onCreate method of every Android Activity. The onCreate() expects to be called with a Bundle as parameter so we pass savedInstanceState.
What does setOnClickListener do in Android?
setOnClickListener(this); means that you want to assign listener for your Button “on this instance” this instance represents OnClickListener and for this reason your class have to implement that interface. If you have more than one button click event, you can use switch case to identify which button is clicked.
What is retained fragment Android?
Specifically, “retained” means that the fragment will not be destroyed on configuration changes. That is, the Fragment will be retained even if the configuration change causes the underlying Activity to be destroyed.
What is a FragmentManager in Android?
How do I know if my Backstack is empty?
you can use fragment stack while pushing fragments inside it. Use getBackStackEntryCount() to get count. If it is zero, means nothing in backstack.
When do I receive null for savedinstancestate?
Activity A is the main activity, and I always receive null for savedInstanceState in onCreate of its list fragment when returning from a detail view activity B. After many hours, this problem exposed itself to me as a navigation issue in disguise. The following may be relevant to my setup and come from other answers on this page:
How does the NOT NULL constraint work in SQL?
The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
Why is my saved state Null in fragment?
If you are trying to use outState to save the state and destroy the fragment by navigating to another fragment, it will not work, you have in this case to save your state permanently in either sharedPreferences or if it’s big and you want to be more organized you can use any persistence lib like Room, Realm.etc.
Why does oncreate always call onsaveinstancestate?
Did you check if you have an Id set for that view ( if a view it is/has…). onSaveInstanceState () is not called otherwise. Check this link. The state saved in this manner is not persisted. If the whole application is killed as you are doing during debugging, the bundle will always be null in onCreate.