NullPointerException and findViewById()

Question

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My Android app crashed. I checked the stacktrace from the logcat and found that the cause is a NullPointerException at the line

myEditText.setText(myString);

What is the problem and how do I fix it?

@4castle This question is more specific. Of course, I should have found a way to include a link to that question in mine. — Code-Apprentice, Sep 11 '16 at 02:09

score 2 · Answer 1 · answered Sep 11 '16 at 01:49

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Please provide more detail about your code. I think you didn't initialize myEditText correctly

something like this:

EditText myEditText = findViewById(R.id.xxx);

answered Sep 11 '16 at 01:49

xxx

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score 2 · Answer 2 · answered Sep 11 '16 at 02:05

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you didn't initialize myEditText reference to any EditText Object in the activity which holds it..

kindly be sure you initialize it and you use that statement in the right place.

answered Sep 11 '16 at 02:05

Mohamed Fadel Buffon

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Code-Apprentice · Answer 3 · 2016-09-11T02:53:33.217

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The error message indicates that myEditText has not been initialized correctly. First, you need to be sure that you call findViewById(). For example

myEditText = findViewById(R.id.text);

If you already did this, double-check that the resource id matches the one declared in the XML layout file for your activity or fragment.

Also, you may have forgot to call setContentView() in your activity's onCreate() method.

edited Sep 11 '16 at 02:53

answered Sep 11 '16 at 01:53

Code-Apprentice

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Also, If you try to get a reference for a `View` before calling `setContentView` – jlynch630 Sep 11 '16 at 02:17
@jDawg Good one. I'll add that. – Code-Apprentice Sep 11 '16 at 02:48

score 1 · Answer 4 · answered Sep 11 '16 at 02:53

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Remember one thing whenever you get null pointer exception in any findViewById it can only happens if id declared inside XML and java files are not matching or say from java side you are trying to access Id which don't even declared in XML side.

Another point i want to make is you are using setText() method and you are passing String object now keep in mind that it can also arise null pointer if it's a null object and don't have any value.

answered Sep 11 '16 at 02:53

TapanHP

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Thanks for the answer. Note that this is not the only reason for a NPE in this situation. – Code-Apprentice Sep 11 '16 at 02:56
What is another reason? Can u please let me know – TapanHP Sep 11 '16 at 03:09
Please read the other answers here. – Code-Apprentice Sep 11 '16 at 03:36

score 1 · Answer 5 · answered Sep 11 '16 at 04:46

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use "" and then append your string. its probably your myString returning null.

myEditText.setText("" + myString);

answered Sep 11 '16 at 04:46

Kshitiz Mishra

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Thanks for pointing this out. This is actually a fault in my contrived example. – Code-Apprentice Sep 11 '16 at 04:48

NullPointerException and findViewById()

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