弹出对话框

private void showNoticeDialog() {        // 构造对话框        AlertDialog.Builder builder = new AlertDialog.Builder(HomeActivity.this);        builder.setMessage("检测到当前网络环境为非WIFI环境，为避免不必要的流量开销，是否前往修改？");        // 更新        builder.setPositiveButton("前往设置", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialog, int which) {                dialog.dismiss();                startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));            }        });        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialog, int which) {                dialog.dismiss();            }        });        android.app.Dialog noticeDialog = builder.create();        noticeDialog.show();    }