android-测试是否字段是空的，而且防止用户保存到sqlite

显示一个提示,他们必须把字段完全。但是这段代码仍然接受即使名字是null和号码是进入。
我怎么能够测试字段是否被用户填全？我想要显示一个提示，希望他们把字段都填全。但是下边这段代码，即使名字是空的，仍然是接收。
    public void onClick(View arg0)
    {
        switch(arg0.getId())
        {
        case R.id.bSQLUpdate:
            boolean diditwork = true;
            try
            {
            String name = sqlName.getText().toString();
            String number = sqlNumber.getText().toString();

            GroupDb entry = new GroupDb(ContactDb.this);
            entry.open();
            if(name != null && number != null)
            {
                if((!entry.hasDuplicateNameNumber(name, number)) )
                {
                    entry.createEntry(name, number);

                }
                else
                {
                    diditwork = false;
                    Dialog d = new Dialog(this);
                    d.setTitle("Error");
                    TextView tv = new TextView(this);
                    tv.setText("Duplicate name or number. Please try again.");
                    d.setContentView(tv);
                    d.show();
                    sqlName.setText("");
                    sqlNumber.setText("");
                }
            }
            else
            {
                diditwork = false;
                Dialog d = new Dialog(this);
                d.setTitle("Error");
                TextView tv = new TextView(this);
                tv.setText("Please fill up all fields. Please try again.");
                d.setContentView(tv);
                d.show();
                sqlName.setText("");
                sqlNumber.setText("");
            }

            entry.close();
            }
            catch(Exception e)
            {
                diditwork = false;
                String error = e.toString();
                Dialog d = new Dialog(this);
                d.setTitle("Update failed");
                TextView tv = new TextView(this);
                tv.setText(error);
                d.setContentView(tv);
                d.show();
                sqlName.setText("");
                sqlNumber.setText("");
            }
            finally
            {
                if(diditwork)
                {
                    Dialog d = new Dialog(this);
                    d.setTitle("Contact list updated");
                    TextView tv = new TextView(this);
                    tv.setText("Success");
                    d.setContentView(tv);
                    d.show();
                    sqlName.setText("");
                    sqlNumber.setText("");
                }
            }
            break;

        case R.id.bSQLOpenView:
            Intent intent = new Intent();
            intent.setClass(ContactDb.this, CustomListView.class);

            startActivityForResult(intent, 0);
            break;

        }

    }