bundle 传送 List> 出错，求解

[时钟II]

代码如下：
public void onCreate(Bundle savedInstanceState) {
// TODO 自动生成的方法存根
System.out.println("dddddddd------1");
list = (List<HashMap<String, String>>) savedInstanceState.getSerializable("list");
System.out.println("dddddddd------2");
super.onCreate(savedInstanceState);
}

public static DownloadFragment setInstance(List<HashMap<String, String>> list){
DownloadFragment mDownloadFragment = new DownloadFragment();
Bundle args = new Bundle();
args.putSerializable("list", (Serializable) list);
mDownloadFragment.setArguments(args);
return mDownloadFragment;
}
在list = (List<HashMap<String, String>>) savedInstanceState.getSerializable("list"); 位置说
类型安全：未经检查的从 Serializable 到 List<HashMap<String,String>> 的强制类型转换
能打印出dddddd----1 打印不出 ddddddd----2
List<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();