[Solved] Add items to listview from other activity

by 


new View.OnClickListener() {
                      public void onClick(View arg0) {
                          EditText edit = (EditText) findViewById(R.id.tskname);
                          Intent i = new Intent(AddTask.this,
                                  MainActivity.class);
                          //Bundle bundle = new Bundle();
                          String TaskName = edit.getText().toString();
                          //bundle.putString("NewTask", TaskName);
                          i.putExtra("NewTask", TaskName);
                          i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                          //i.putExtras(bundle);
                          startActivity(i);
                      }
                  });

You are starting a new Activity each time you want to add an item.
Consider using 

startActivityForResult()

Link to Android Documentation

Even if startActivityForResult() is IMHO the best way to fix your problem, i’ll give you a hint why it doesn’t show your “old” data.
You don’t finish your first Activity when going to the Second. You could aswell just finish your second activity and your MainActivity would run into

onResume()

therefor check the Android lifecycle

solved Add items to listview from other activity