public void onClick(View v) {
    try {
        String tmp=texts[selectEdit].getText().toString();
        switch (n) {
            case 3: texts[selectEdit].setText(tmp.substring(0,tmp.length()-1));
                    break;//get cursor position and delete char
            case 7:{
                    Precision.performClick();
                    break;
                    }//spinner for selecting precision
            case 11:{
                    if(!tmp.contains("E"))
                        texts[selectEdit].setText(tmp+""+keybuttons[n].getText());
                    break;
                    }//check for E if dont have do default case
            case 15:{
                    //calculator.num=n;
                    //startActivity(new Intent("com.easyPhys.start.calculator"));
                    break;
                    }//open Calculator
            case 16: break;//next field
            case 17: {
                      onBackPressed();
                      break;
                     }//simulate back button
            default:{
                    texts[selectEdit].setText(tmp+""+keybuttons[n].getText());
                    //get cursor start and end and get entire String
                    // replace selected String with button text
                    //insert back
                    break;
                    }
            }//end of switch
    }//end of try