filewriter - Android: Write file from other class nullpointerexception -

I am trying to write a file from another category, but I get a null portefecope that I can not solve . The following code can be used primarily without any problem, but when I try to use it in my second class, I get an error.

  Public Zero WriteFile () {string text = "Hello world"; String filename = "TestFile.txt"; FileOutputStream fileApricotStream; Main activity maObj = new main activity (); Try {FileOutputStream = maObj.openFileOutput (fileName, maobj.MODE_PRIVATE); FileOutputStream.write (text.getBytes ()); FileOutputStream.close (); } Hold (IOException e) {e.printStackTrace (); }}  

You passed the activity reference instead of creating a new activity instance in the method of writing Do

  write public zip file (reference reference) {  
 and remove 
 mainActivity maObj = new MainActivity ();  As can be done in an Android application like this can not be instantified, change 
 
  fileOutputStream = maObj.openFileOutput (filename, maobj.MODE_PRIVATE);  
 
 to 
 
  fileOutputStream = context.openFileOutput (filename, theme. MODE_PRIVATE);  
 
 Once completed, your method should look like this: 
 
  write public zero file (reference reference) {string text = "Hello world"; String filename = "TestFile.txt"; FileOutputStream fileApricotStream; Try {FileOutputStream = context.openFileOutput (filename, reference. MODE_PRIVATE); FileOutputStream.write (text.getBytes ()); FileOutputStream.close (); } Hold (IOException e) {e.printStackTrace (); }}  
 
 Now call your method as 
 
  file (main activity) as this;  
 
 to  main activity  class.