java - SharedPreferences 会覆盖其他值吗？

Question

我是 android 新手。这里我制作了简单的联系人列表应用程序。当用户单击联系人项目时，联系人会添加到 Collection 夹列表中。但问题是，当用户单击第一个联系人项目添加 Collection 夹时，然后用户单击第二个联系人，但第一个项目被自动删除。共享首选项覆盖其他值，我想在列表中添加项目，那么我如何在 Collection 夹列表中添加联系人。

第一个 fragment :

imageViewfavourite.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
                SharedPreferences.Editor editor = preferences.edit();

                editor.putString("name1", Pname);
                editor.putString("number1", Pnumber);
                editor.putString("image1", temp);
                editor.putInt("pos", position);

                Log.e("a", "name1" + Pname);
                Log.e("a", "number1" + Pnumber);
                Log.e("a", "image1" + temp);

                editor.commit();

            }
        });

第二个 fragment :

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

View view = inflater.inflate(R.layout.fragment_fragment_fv, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.favourite_list);
selectUsers = new ArrayList<DataContact>();

SharedPreferences preferences = getActivity().getPreferences(0);
String Pname = preferences.getString("name1", "");
String Pnumber = preferences.getString("number1", "");
String Pimage = preferences.getString("image1", "");

byte[] encodeByte = Base64.decode(Pimage, Base64.DEFAULT);
bitmap = BitmapFactory.decodeByteArray(encodeByte, 0, encodeByte.length);

Log.v("name1", Pname);
Log.v("number1", Pnumber);
Log.v("image1", Pimage);

DataContact selectUser = new DataContact();
selectUser.setName(Pname);
selectUser.setPhone(Pnumber);
selectUser.setThumb(bitmap);
selectUsers.add(selectUser);

adapter = new AdapterFv(getActivity(), "");
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
llm.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(llm);
adapter.setData(selectUsers);
recyclerView.setAdapter(adapter);

return view;
}

Answer 1

检查 api documentation在提问之前。

解释

SharedPreferences 支持存储数据(1:1 键值匹配)，因此一个键只能有一个数据项。

Storable Types

• boolean
• float
• int
• long
• String
• Set<String>

简单的解决方案

// in Second Fragment 
String Pname = preferences.getString("name2", "");
String Pnumber = preferences.getString("number2", "");
String Pimage = preferences.getString("image2", "");

引用

https://developer.android.com/reference/android/content/SharedPreferences.html