更新提示框

 final AlertDialog.Builder builder = new AlertDialog.Builder(con);        builder.setTitle("更新提醒");        builder.setMessage(desc);        // builder.setCancelable(false);        builder.setOnCancelListener(new DialogInterface.OnCancelListener() {            @Override            public void onCancel(DialogInterface dialog) {

            }        });        builder.setNegativeButton("下次再说", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialog, int which) {            }        });        builder.setPositiveButton("立刻更新", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialog, int which) {                System.out.println("下载：" );//                download(downloadurl);            }

        });        builder.show();