Null object reference when calling a constructed textview

Question

I created a text view dynamically , but the problem is that when I want to set the text size of this text view on a button click, I get:

error: null object reference.

the code:

//in Main class

TextView textview;


//creating the text view on button click
Button mbutton1=(Button)findViewById(R.id.button1);
mbutton1.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
 textview=new TextView(this);

//adding the view to the relativelayout
RelativeLayout.LayoutParams params=new RelativeLayout.LayoutParams
(ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT );
textview.setLayoutParams(params);

//making object for Relativelayout and add the view to activity
RelativeLayout relativel=(RelativeLayout)findViewById(R.id.relativelayout);
relative1.addView(textview);
}
});

//now here is the button which must set the size of this text view
 Button mbutton2=(Button)findViewById(R.id.button2);
mbutton2.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
textview.setsize(20);

}
});
//And the error is when I click button 2 it says null object reference.

Edit: This question was closed as duplicate of another but in the other question the answers were why (null object reference)error happens , I know the causes for the problem what I need is an answer on how to set a value for a non existing object in an activity.

Have you clicked on `mbutton1` before clicking on `mbutton2` ? — ρяσѕρєя K, Dec 26 '16 at 05:41
textview=new TextView(this); keep this outside of button click — Manohar, Dec 26 '16 at 05:41
create outside but add textview to relative1 inside mbutton1. Creating outside wont make any difference — Manohar, Dec 26 '16 at 05:45
Initialize your textview in onCreate method. write this line `textview=new TextView(this);` in onCreate method. — Chirag Savsani, Dec 26 '16 at 05:52
@Redman I did what you told me but now I can add the text view to my activity on the first click of mbutton1 the second click on mbutton1 crashes the app instead of adding another textview. — Hasan B.T, Dec 26 '16 at 05:53
There is no setsize method for textview, instead you might want setTextSize() — Ezio, Dec 26 '16 at 05:59
@HasanB.T you have to set Activity Context ot Application Context instead of this. Example, Change your code`textview=new TextView(this);` to `textview=new TextView(YourActivity.this);` — Chirag Savsani, Dec 26 '16 at 06:04
@ChiragSavsani the problem is that the system is not finding an object called text view because if I didnt click mbutton1 then text view will never be created and this why when I click mbutton2 the error starts.But how can that be fixed. — Hasan B.T, Dec 26 '16 at 06:19
@HasanB.T Please open this question so I can add answer to your question. I solved your problem. — Chirag Savsani, Dec 26 '16 at 06:23
@HasanB.T Please refer this link for info. http://meta.stackoverflow.com/questions/260607/how-to-remove-duplicate-mark-from-my-question — Chirag Savsani, Dec 26 '16 at 06:47
@ChiragSavsani I edited the question as they said , I dont know if that will work. — Hasan B.T, Dec 26 '16 at 07:01
I don't know why people here are in so much hurry to close any question — Ezio, Dec 26 '16 at 09:23
Ya true. Many people don't see problem. They find out just one word like `NullPointerExceeption`. If any found `NullPointerExceeption` they close question like this. — Chirag Savsani, Dec 26 '16 at 09:36

score 0 · Answer 1 · answered Dec 26 '16 at 05:42

0

You must click the mbutton1 before click mbutton2

answered Dec 26 '16 at 05:42

Kingyal

63
8

I want to set the text of the text view before posting it to the activity. – Hasan B.T Dec 26 '16 at 05:44

Null object reference when calling a constructed textview

1 Answers1