如何使用sharedpreference在listview中保存项目

Question

I am just learning android studio.

then, I want to save my list item in my listview

only using shared preference.

I succeeded to Add and save item.

but it can save only one row!

then I input any key. it just changes key before adding the item.

so, how to adding list and save ? ! please help me

enter code here

// listview save sharedpreference
private void savePreferences () {
    String ten = editTen.getText().toString();
    String sdt = editSDT.getText().toString();
    SharedPreferences pref = getSharedPreferences("pref", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = pref.edit();
    editor.putString("list1", ten);
    editor.putString("list2", sdt);
    editor.commit();
}

// load sharedpreference

private void getPreferences() {
        SharedPreferences pref = getSharedPreferences("pref", Context.MODE_PRIVATE);
        String date = pref.getString("list1", null);
        String name = pref.getString("list2", null);
            arrSinhVien = new ArrayList<SinhVien>();
            arrSinhVien.add(new SinhVien(R.drawable.luan, date, name));
            myadapter = new CustomAdapter(this, R.layout.activity_diary_item, arrSinhVien);

    }

Answer 1

The Shared preferences is not use to save the list of items, Its just key value pair data structure to save small amount of data of your application.
In your snippet you overwrite the previous data with new one.
But still if you want to save the list data, I suggest that to use the JSON array and put that Array into the shared preferences.
The Code is like as follows.

 JSONArray jsArr=new JSONArray(); JSONObject jsObj=new JSONObject(); jsObj.putString("ten",editTen.getText().toString()); jsObj.putString("sdt",editSDT.getText().toString()); //Add this object to your JSONArray jsArr.add(jsObj); //Serialize your Json Array and save to shared preferences. savePreferences(jsArr); 

private void savePreferences (JSONArray jsArr) {
SharedPreferences pref = getSharedPreferences("pref", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = pref.edit();
editor.putString("list", jsArr.toString());
editor.commit();
}

And use this as follows

private void getPreferences() {
    SharedPreferences pref = getSharedPreferences("pref", Context.MODE_PRIVATE);
    arrSinhVien = new ArrayList<SinhVien>();
    String jsArrList = pref.getString("list", null);
    JSONArray jsArr=new JSONArray(jsArrList); 
    for(JSONObject obj:jsArr){
      String date=obj.getString("ten");
      String name=obj.getString("sdt");
      arrSinhVien.add(new SinhVien(R.drawable.luan, date, name));
    }
    myadapter = new CustomAdapter(this, R.layout.activity_diary_item, arrSinhVien);

}

Hope this will help you..