Button btnSave = (Button) findViewById(R.id.Button01);
        btnSave.setOnClickListener(new View.OnClickListener()
        {
        	EditText mUserText = (EditText) findViewById(R.id.EditText01);
        	Editable oldText = mUserText.getText();

            public void onClick(View v) {
            	First T=new First();
            	String re = T.run(String.valueOf(oldText));
            	DisplayToast("The postfix and result of " + mUserText.getText() + " is "+ re);
            	T = null;
            }
        });