为共享首选项传递不同的值

Question

我是一个没有经验的 Android 初学者！

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。

所以类别将user_id和api_key作为参数，然后子类别将user_id、cat_id 和 api_key 作为参数。

我使用 JSONObject 来解析类别，并尝试将 类别 ID 保存在 shared preferences.

中

所以在 SubcategoryFragment 之后，我再次调用了 shared preferences，它运行。但我注意到对于所有类别项目，只有一个 id 用于子类别。所以基本上多个类别都在调用同一个子类别。

我认为这是因为在我的 SubcategoryFragment 代码中，我只调用了一次共享首选项的编辑器，而在 CategoryFragment 中，我将编辑器放在 JSON 数组的 for 循环中。

请告诉我您的想法。我很感激！

我保存 categoryID 的 CategoryFragment：


    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
    }

我的 SubcategoryFragment 使用它：

    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覆盖了具有相同键的值。例如，您的 "chamber" SharedPreferences -

中的键 "scid" 只有一个值

所以如果你这样做 -

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

键 "scat_id" 的值将在每次调用时被覆盖。

溶胶。 - 您可以将完整的 JSONObject 另存为 String 在您的 SharedPreferences 中，例如 -

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

然后解析和重用它。

更新：

像这样更新您的代码 -

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

//Save in SharedPref
    editor.putString("api_response", it)
    editor.commit()

//Use a common parsing function
scatList = getParsedData(it)          //it or from SharedPref

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

}

// 解析数据的常用函数

fun getParsedData(strResponse: String?): List<SubCategoryItem>{
  if(!strResponse.isNullOrEmpty()){
    try{
      val list = ArrayList<SubCategoryItem>()
      var jsonObject = JSONObject(it)
      var jsonArraySCat = jsonObject.getJSONArray("subcategory")

repeat(jsonArraySCat.length()){                    //use repeat than for loop
  jsonArraySCat.getJSONObject(it).run{
    SubCategoryItem(getString("scid"), scats.getString("scname"), scats.getString("scdiscription"), scats.getString("scimageurl")).also{
      list.add(it)
    }
  }
}
return list    //return parsed data list
}catch(e: JSONException){
  Log.d(TAG, "Parse Exception $e")  
}
}
return ArrayList()  //return empty list
}

为共享首选项传递不同的值

Passing different values for Shared Preferences

android

json

sharedpreferences

kotlin

android-volley