CODEWITHSUNDEEP
androidruntime-error
Xaloju
Xaloju

Reputation: 195

Why my app crash when I switch fragments fast?

My apps crash sometimes when I change the fragment with the navigationDrawer. The fatal error isn't helping much, How can I solve this problem? Thx

FATAL EXCEPTION: main
     Process: acr.acr_app, PID: 29425
   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:359)
   at android.view.View.<init>(View.java:3656)
   at android.view.View.<init>(View.java:3751)
   at android.view.ViewGroup.<init>(ViewGroup.java:492)
   at android.widget.LinearLayout.<init>(LinearLayout.java:200)
   at android.widget.LinearLayout.<init>(LinearLayout.java:196)
   at android.widget.LinearLayout.<init>(LinearLayout.java:192)
   at android.widget.LinearLayout.<init>(LinearLayout.java:188)
   at android.widget.TableRow.<init>(TableRow.java:61)
   at acr.acr_app.MyFragment3$2.onChildAdded(MyFragment3.java:170)
   at com.google.android.gms.internal.zzaer.zza(Unknown Source)
   at com.google.android.gms.internal.zzagp.zzSu(Unknown Source)
   at com.google.android.gms.internal.zzags$1.run(Unknown Source)
   at android.os.Handler.handleCallback(Handler.java:739)
   at android.os.Handler.dispatchMessage(Handler.java:95)
   at android.os.Looper.loop(Looper.java:135)

Fragment3 line170: onStart() listener

  tableRow = new TableRow(getContext());
  tableRow.setLayoutParams(new TableLayout.LayoutParams(
  TableLayout.LayoutParams.WRAP_CONTENT,
  TableLayout.LayoutParams.WRAP_CONTENT, 1.0f));

Upvotes: 8

Views: 2602

Answers (3)

Ronald
Ronald

Reputation: 1

I faced the same issue and I fixed it. It was because I was using requireView() and requireContext() everywhere. When we try to move from one fragment to other fast, as the onViewCreated() is half way through, the requireView() and requireContext() will not be able to get the view or context, thus it will throw an error and the app will crash. To prevent that, save the view and context in a variable at the beginning and reuse that variable.

Example:

private lateinit var myContext : Context

and inside onViewCreated() add:

myContext = getContext()

then reuse the variable:

if(isAdded()){
tableRow = new TableRow(myContext);
tableRow.setLayoutParams(new TableLayout.LayoutParams(
TableLayout.LayoutParams.WRAP_CONTENT,
TableLayout.LayoutParams.WRAP_CONTENT, 1.0f));

}

Upvotes: 0

Z.sin
Z.sin

Reputation: 1

What is your fragment's working mode of fragmentManager? Is it :replace or showhide? It will crash if you switch fast, because your fragment has not completed initialization when it attaches to FragmentActivity. Try something like this:

Upvotes: 0

MrJM
MrJM

Reputation: 1214

The reason for this crash is that the fragment is still executing code while it is already detached from your Activity.

In your case the Fragment is already switched to another Fragment when it reaches the getContext(). Because getContext() is looking for the Activity (which the fragment is no longer attached to) it will cause a nullpointer exception.

Try the following:

 if(isAdded()){
    tableRow = new TableRow(getContext());
    tableRow.setLayoutParams(new TableLayout.LayoutParams(
    TableLayout.LayoutParams.WRAP_CONTENT,
    TableLayout.LayoutParams.WRAP_CONTENT, 1.0f));
 }

Upvotes: 6

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