保存ArrayList到SharedPreferences

I have an ArrayList with custom objects. Each custom object contains a variety of strings and numbers. I need the array to stick around even if the user leaves the activity and then wants to come back at a later time, however I don't need the array available after the application has been closed completely. I save a lot of other objects this way by using the SharedPreferences but I can't figure out how to save my entire array this way. Is this possible? Maybe SharedPreferences isn't the way to go about this? Is there a simpler method?

当前回答

嘿，朋友们，我没有使用Gson库就得到了上述问题的解决方案。我在这里发布源代码。

1.变量声明，即

  SharedPreferences shared;
  ArrayList<String> arrPackage;

2.变量初始化，即

 shared = getSharedPreferences("App_settings", MODE_PRIVATE);
 // add values for your ArrayList any where...
 arrPackage = new ArrayList<>();

3.使用packagesharedPreferences()将值存储到sharedPreference:

 private void packagesharedPreferences() {
   SharedPreferences.Editor editor = shared.edit();
   Set<String> set = new HashSet<String>();
   set.addAll(arrPackage);
   editor.putStringSet("DATE_LIST", set);
   editor.apply();
   Log.d("storesharedPreferences",""+set);
 }

4.使用retriveSharedValue()检索sharedPreference的值:

 private void retriveSharedValue() {
   Set<String> set = shared.getStringSet("DATE_LIST", null);
   arrPackage.addAll(set);
   Log.d("retrivesharedPreferences",""+set);
 }

我希望这对你有帮助…

2016-04-26 19:58:58

其他回答

//Set the values
intent.putParcelableArrayListExtra("key",collection);

//Retrieve the values
ArrayList<OnlineMember> onlineMembers = data.getParcelableArrayListExtra("key");

2015-10-01 10:13:53

/**
 *     Save and get ArrayList in SharedPreference
 */

JAVA:

public void saveArrayList(ArrayList<String> list, String key){
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(activity);
    SharedPreferences.Editor editor = prefs.edit();
    Gson gson = new Gson();
    String json = gson.toJson(list);
    editor.putString(key, json);
    editor.apply();    

}

public ArrayList<String> getArrayList(String key){
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(activity);
    Gson gson = new Gson();
    String json = prefs.getString(key, null);
    Type type = new TypeToken<ArrayList<String>>() {}.getType();
    return gson.fromJson(json, type);
}

科特林

fun saveArrayList(list: java.util.ArrayList<String?>?, key: String?) {
    val prefs: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(activity)
    val editor: Editor = prefs.edit()
    val gson = Gson()
    val json: String = gson.toJson(list)
    editor.putString(key, json)
    editor.apply()
}

fun getArrayList(key: String?): java.util.ArrayList<String?>? {
    val prefs: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(activity)
    val gson = Gson()
    val json: String = prefs.getString(key, null)
    val type: Type = object : TypeToken<java.util.ArrayList<String?>?>() {}.getType()
    return gson.fromJson(json, type)
}

2019-06-20 09:21:25

这应该可以工作:

public void setSections (Context c,  List<Section> sectionList){
    this.sectionList = sectionList;

    Type sectionListType = new TypeToken<ArrayList<Section>>(){}.getType();
    String sectionListString = new Gson().toJson(sectionList,sectionListType);

    SharedPreferences.Editor editor = getSharedPreferences(c).edit().putString(PREFS_KEY_SECTIONS, sectionListString);
    editor.apply();
}

他们，要抓住它才:

public List<Section> getSections(Context c){

    if(this.sectionList == null){
        String sSections = getSharedPreferences(c).getString(PREFS_KEY_SECTIONS, null);

        if(sSections == null){
            return new ArrayList<>();
        }

        Type sectionListType = new TypeToken<ArrayList<Section>>(){}.getType();
        try {

            this.sectionList = new Gson().fromJson(sSections, sectionListType);

            if(this.sectionList == null){
                return new ArrayList<>();
            }
        }catch (JsonSyntaxException ex){

            return new ArrayList<>();

        }catch (JsonParseException exc){

            return new ArrayList<>();
        }
    }
    return this.sectionList;
}

这对我很管用。

2018-07-26 07:59:21

你可以使用Gson库保存字符串和自定义数组列表。

首先你需要创建一个函数来保存数组列表到SharedPreferences。

public void saveListInLocal(ArrayList<String> list, String key) {

        SharedPreferences prefs = getSharedPreferences("AppName", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();
        Gson gson = new Gson();
        String json = gson.toJson(list);
        editor.putString(key, json);
        editor.apply();     // This line is IMPORTANT !!!

    }

你需要创建一个函数来从SharedPreferences获取数组列表。

public ArrayList<String> getListFromLocal(String key)
{
    SharedPreferences prefs = getSharedPreferences("AppName", Context.MODE_PRIVATE);
    Gson gson = new Gson();
    String json = prefs.getString(key, null);
    Type type = new TypeToken<ArrayList<String>>() {}.getType();
    return gson.fromJson(json, type);

}

如何调用保存和检索数组列表函数。

ArrayList<String> listSave=new ArrayList<>();
listSave.add("test1"));
listSave.add("test2"));
saveListInLocal(listSave,"key");
Log.e("saveArrayList:","Save ArrayList success");
ArrayList<String> listGet=new ArrayList<>();
listGet=getListFromLocal("key");
Log.e("getArrayList:","Get ArrayList size"+listGet.size());

不要忘记在你的应用级别build.gradle中添加gson库。

实现“com.google.code.gson: gson: 2.8.2”

2018-04-19 09:35:12

使用这个对象——> TinyDB——Android-Shared-Preferences-Turbo非常简单。