alert dialog with 2 buttons android

AlertDialog.java

protected void AlertDialog() {
  AlertDialog.Builder builder = new Builder(Main.this);
  builder.setMessage("确认退出吗？");
  builder.setTitle("提示");
  builder.setPositiveButton("确认", new OnClickListener() {
   @Override
   public void onClick(DialogInterface dialog, int which) {
    dialog.dismiss();
    Main.this.finish();
   }
  });
  builder.setNegativeButton("取消", new OnClickListener() {
   @Override
   public void onClick(DialogInterface dialog, int which) {
    dialog.dismiss();
   }
  });
  builder.create().show();
 }