为共享首选项传递不同的值

Question

我是一位没有经验的Android学习者！

所以我正在学习，在我的项目中，我必须使用url和shared preferences (Volley)来显示Recycler View中的项目。

因此categories将user_id和api_key作为参数，然后subcategories将user_id，cat_id和api_key作为参数。

我使用JSONObject解析类别，并且尝试将类别ID保存在shared preferences中。

所以在SubcategoryFragment之后，我再次调用了shared preferences，然后它运行了。但是我注意到，对于所有类别项目，只有一个ID用于子类别。因此，基本上有多个类别都在调用同一个子类别。

我想是因为在我的SubcategoryFragment代码中，我只调用了共享首选项的编辑器，而在CategoryFragment中，我将编辑器置于JSON数组的for循环中。

请让我知道您的想法。我很欣赏！

保存了categoryID的我的类别片段：

    var catList = ArrayList<CategoryItem>()

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

        // Inflate the layout for this fragment
        var view =  inflater.inflate(R.layout.fragment_main_act, container, false)

        //Recycler view
        view.recyclerViewCat.layoutManager = LinearLayoutManager(context)

        var sp: SharedPreferences = this.activity!!.getSharedPreferences("chamber", Context.MODE_PRIVATE)
        var editor = sp.edit()


        var iD = sp.getString("user_id", "Default")
        var apiKey = sp.getString("user_apikey", "Default")

        val url = "XXXX.php?cust_category.php?api_key=$apiKey&user_id=$iD"

        var stringRequest = StringRequest(Request.Method.GET, url,

            Response.Listener {

                var jsonObject = JSONObject(it)

                var jsonArrayCats =jsonObject.getJSONArray("category")

                for(i in 0 until jsonArrayCats.length()){

                    var cats =jsonArrayCats.getJSONObject(i)

                    var cID = cats.getString("cid")
                    var cName = cats.getString("cname")
                    var cDes = cats.getString("cdiscription")
                    var cImg = cats.getString("cimagerl")

                    catList.add(CategoryItem(cID, cName, cDes, cImg))

                    editor.putString("cat_id", cID)
                    editor.putString("cat_name", cName)
                    editor.putString("cat_des", cDes)
                    editor.putString("cat_Img", cImg)

                }
                editor.apply()

                val adapter = CatAdapter(catList, view.context)
                view.recyclerViewCat.adapter = adapter

            },
            Response.ErrorListener {
                Toast.makeText(view.context, "invalid api key or user id", Toast.LENGTH_SHORT).show()
            }

        )

        Volley.newRequestQueue(view.context).add(stringRequest)

        return view
    }

以及我使用它的SubcategoryFragment：

    var scatList = ArrayList<SubCategoryItem>()

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        var view = inflater.inflate(R.layout.fragment_sub_category, container, false)

        view.recyclerViewSubCat.layoutManager = LinearLayoutManager(context)

        var sp: SharedPreferences = this.activity!!.getSharedPreferences("chamber", Context.MODE_PRIVATE)
        var editor = sp.edit()

        var catId = sp.getString("cat_id", "Default")
        var apiKey = sp.getString("user_apikey", "Default")
        var userId = sp.getString("user_id", "Default")

        val url = "XXXXX.php?Id=$catId&api_key=$apiKey&user_id=$userId"

        var stringReq = StringRequest(Request.Method.GET, url,
            Response.Listener {

                var jsonObject = JSONObject(it)
                var jsonArraySCat = jsonObject.getJSONArray("subcategory")

                for(i in 0 until jsonArraySCat.length()){

                    var scats = jsonArraySCat.getJSONObject(i)

                    var scID = scats.getString("scid")
                    var scName = scats.getString("scname")
                    var scDes = scats.getString("scdiscription")
                    var scImg = scats.getString("scimageurl")

                    editor.putString("scat_id", scID)
                    editor.putString("scat_name", scName)
                    editor.putString("scat_des", scDes)
                    editor.putString("scat_Img", scImg)

                    scatList.add(SubCategoryItem(scID, scName, scDes, scImg))

                }

                editor.commit()

                val adapter = SubCatAdapter(scatList, view.context)
                view.recyclerViewSubCat.adapter = adapter

            },

            Response.ErrorListener {
                Log.e("ERROR", it.message.toString())
                Toast.makeText(view.context, "No data", Toast.LENGTH_SHORT).show()
            }

        )

        Volley.newRequestQueue(view.context).add(stringReq)

Answer 1

这是因为SharedPreferences会覆盖具有相同键的值。例如，“房间”中的键“ scid”只有一个值SharedPreferences-

所以，如果您这样做-

for(i in 0 until jsonArraySCat.length()){
    editor.putString("scat_id", scID)
}

比每次调用键“ scat_id”的值都要大。

Sol。 --您可以在JSONObject中将完整的String保存为SharedPreferences，例如-

editor.putString("jsonResponse", jsonObject.toString())

并且比解析并重用它。