I am having some trouble understanding sharedPreferences and how to save and retrieve a list of objects between different activities. I followed the steps from multiple other questions, I will list them below,but I keep running into a mismatch in conversion no matter how I change it. I do get access to the list saved in sharedPreference but I am unable to convert it back to the object list. My main activity code that does an http request and saves the response object list to sharedpreferences and finally starts the next intent is:
private fun getItems(authResponse: AuthResponseModel) {
val url = "/Api/items";
val formBody = FormBody.Builder()
.add("token", authResponse.cloverToken.toString())
.build()
// creating request
var request = Request.Builder()
.addHeader("Authorization", "Bearer " + authResponse.token.toString())
.url(url)
.post(formBody)
.build()
var client = OkHttpClient();
runOnUiThread{
client.newCall(request).enqueue(object : Callback {
override fun onResponse(call: Call, response: Response) {
var response = response.body?.string();
//save auth token
val gson = Gson()
System.out.println("clover 2: " + gson.toJson(response));
val preferences = getSharedPreferences("items", MODE_PRIVATE)
preferences.edit().putString("items", gson.toJson(response)).commit()
val intent = Intent(this@MainActivity, OrderActivity::class.java)
intent.putExtra("SHOW_WELCOME", true)
startActivity(intent)
finish()
}
})
}
}
How I retrieve the data in the other activity is below:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_order)
initialize()
var arrayItems: List<ItemModel>;
initPermissions()
val itemList = getSharedPreferences("items", MODE_PRIVATE)
val gson = Gson()
if (itemList != null) {
val type = object : TypeToken<List<ItemModel>>() {}.type
arrayItems = gson.fromJson(gson.toJson(itemList), type)
println("here items " +arrayItems.toString())
}
//this.items = (itemList);
}
I need the items to be a list of ItemModel objects that are returned from sharedpreferences. My main errors I am getting are with the conversions. Let me know if any further information is needed and I will update my question.
The ItemModel code is:
package com.robotemi.sdk.dinengo.models;
import java.util.ArrayList;
public class ItemModel {
private String id;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private String name;
private String alternateName;
private String code;
private String priceType;
private String unitName;
private boolean sku;
private boolean isRevenue;
private boolean available;
private boolean autoManage;
private boolean defaultTaxRates;
private double price;
private double cost;
private double stockCount;
private int modifiedTime;
public ItemModel() {}
public ItemModel(ItemModel itemModel) {
this.id = itemModel.id;
this.name = itemModel.name;
this.alternateName = itemModel.alternateName;
this.code = itemModel.code;
this.priceType = itemModel.priceType;
this.unitName = itemModel.unitName;
this.sku = itemModel.sku;
this.isRevenue = itemModel.isRevenue;
this.available = itemModel.available;
this.autoManage = itemModel.autoManage;
this.defaultTaxRates = itemModel.defaultTaxRates;
this.price = itemModel.price;
this.cost = itemModel.cost;
this.stockCount = itemModel.stockCount;
this.modifiedTime = itemModel.modifiedTime;
}
public ArrayList<ItemModel> ItemModel(ItemModel[] itemModel) {
ArrayList items = new ArrayList<ItemModel>();
for(int i = 0; i <itemModel.length ; i++ ){
ItemModel item = new ItemModel();
item.id = itemModel[i].id;
item.name = itemModel[i].name;
item.alternateName = itemModel[i].alternateName;
item.code = itemModel[i].code;
item.priceType = itemModel[i].priceType;
item.unitName = itemModel[i].unitName;
item.sku = itemModel[i].sku;
item.isRevenue = itemModel[i].isRevenue;
item.available = itemModel[i].available;
item.autoManage = itemModel[i].autoManage;
item.defaultTaxRates = itemModel[i].defaultTaxRates;
item.price = itemModel[i].price;
item.cost = itemModel[i].cost;
item.stockCount = itemModel[i].stockCount;
item.modifiedTime = itemModel[i].modifiedTime;
items.add(item);
}
return items;
}
}
It is giving me the error at this code segment:
arrayItems = gson.fromJson(gson.toJson(itemList), type)
And the error is:
FATAL EXCEPTION: main
Process: com.robotemi.sdk.sample, PID: 16098
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.robotemi.sdk.sample/com.robotemi.sdk.dinengo.OrderActivity}: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:772)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)
Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
at com.google.gson.Gson.fromJson(Gson.java:944)
at com.google.gson.Gson.fromJson(Gson.java:897)
at com.google.gson.Gson.fromJson(Gson.java:846)
at com.robotemi.sdk.dinengo.OrderActivity.onCreate(OrderActivity.kt:162)
at android.app.Activity.performCreate(Activity.java:6266)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
The list of other questions I looked into but no luck:
How to save List<Object> to SharedPreferences?
How to save List<Object> to SharedPreferences?
When trying the suggested answer below, I got the following error:
