getting nullpointer exception when clicking on checkdata button [duplicate]

Answer 1

as you passing the "Object testCertificates" which is null in Activity at line DataManipulator.createCertificatesEntry( (Certificates) testCertificates);

in DataManipulator.createCertificatesEntry method certificates is null so certificates.getBitmap() will thorugh null pointer excption here

  public void createCertificatesEntry(Certificates certificates) 
    { 
     ByteArrayOutputStream out = new ByteArrayOutputStream();
     certificates.getBitmap().compress(Bitmap.CompressFormat.PNG, 100, out);
     ContentValues cv = new ContentValues();
     cv.put(KEY_IMG, out.toByteArray());
     mDb.insert(CERTIFICATES_TABLE, null, cv);
     } 

so either put a check in createCertificatesEntry method

or

pass not null value in DataManipulator.createCertificatesEntry from Activity by using this line

Certificates testCertificates = new Certificates(BitmapFactory.decodeFile(Context.STORAGE_SERVICE));

above

DataManipulator.createCertificatesEntry( (Certificates) testCertificates);