Question

在我的应用中，我想在savedInstanceState()保存数据。我想保存ArrayList<HashMap<String,String>>。到目前为止，我无法做到这一点。这是我困扰我的代码

@Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putParcelableArrayList("places", (ArrayList<? extends Parcelable>) places);

    }

restore（）方法

private void restore(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        //What should i do here! i have try many things but none of them is helping

    }

Answer 1

由于ArrayList，HashMap和String为Serializable，您可以使用Bundle.putSerializable和Bundle.getSerializable

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putSerializable("places", places);
}

private void restore(Bundle savedInstanceState) {
    if (savedInstanceState != null) {
        places = (ArrayList<HashMap<String,String>>) savedInstanceState.getSerializable("places"); 
    }
}

此外，请务必从restore或onRestoreInstanceState

致电onCreate

Answer 2

假设你有：

    ArrayList< HashMap< String,String>> arr = new ArrayList< HashMap< String,String>> ();

    @Override
    protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelableArrayList("places", (ArrayList<    ? extends Parcelable>) arr);
    }

   @Override
   protected void onRestoreInstanceState(Bundle savedInstanceState) {

   ArrayList<HashMap<String,String>> a = (ArrayList<HashMap<String,String>>)savedInstanceState.get("places");
   /*for(int i =0; i< a.size(); i++){
        HashMap<String,String> map = a.get(i);
        for(String s : map.keySet()){
            Log.d("log",s+" :: "+map.get(s));
        }
    }*/
}

保存哈希映射的ArrayList

2 个答案: