arraylist | 易学教程

Convert JsonString to a custom java ArrayList

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问题 My qestion is, how I can convert an saved Json Sting back to an custom ArrayList. This is how I save my ArrayList: public void saveLocList(ArrayList<LocItem> locList) { SharedPreferences.Editor e = returnPref.edit(); Gson gson = new Gson(); String json = gson.toJson(locList); e.putString(LOCLIST, json); e.commit(); } And now, when I restore the ArrayList (Json String) it doesn't work with this code: public ArrayList<LocItem> getLocList() { String json = returnPref.getString(LOCLIST, ""); Type

Pass by reference not returning in RMI for ArrayList

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问题 I've got an RMI call defined as: public void remoteGetCustomerNameNumbers(ArrayList<String> customerNumberList, ArrayList<String> customerNameList) throws java.rmi.RemoteException; The function does a database lookup and populates the two ArrayLists. The calling function gets nothing. I believe this works with Vector types. Do I need to use the Vector, or is there a way to get this to work without making two calls. I've got some other ideas that I'd probably use, like returning a key/value

Using a popup window to add items to arraylist

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问题 I am trying to use a popup sort of panel to enter information in order to add to my arraylist. I found this code import javax.swing.*; public class JOptionPaneMultiInput { public static void main(String[] args) { JTextField xField = new JTextField(15); JTextField yField = new JTextField(15); JTextField zField = new JTextField(15); JPanel myPanel = new JPanel(); myPanel.add(new JLabel("Item Name:")); myPanel.add(xField); myPanel.add(Box.createVerticalStrut(15)); // a spacer myPanel.add(new

java集合类：1、集合框架

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集合框架中的接口集合框架是一个统一的架构，用来表示和操作集合。一个集合是一个对象，它表示了一组对象。集合框架主要是由一些接口、抽象类以及相应的实现类组件。我们来看一下集合框架中的接口所谓框架就是一个类库的集合。集合框架就是一个用来表示和操作集合的统一的架构，包含了实现集合的接口与类。从Collection接口派生出两个接口Set和List，从Set接口派生出SortedSet接口。从Map接口派生出SortedMap接口。需要注意的是：Map接口和Collection接口没有任何关系。接口之间的区别我们来看一下这些接口之间的区别： Collection：集合层次中的根接口，JDK没有提供这个接口直接的实现类。 Set：不能包含重复的元素。 Set接口是从Collection接口继承而来，但是Set接口并没有提供任何新的抽象方法。在Set接口当中它的方法和Collection接口当中的方法是一样的。但是要注意的是，这两个接口它们表示的含义是不一样的。 SortedSet是一个按照升序排列元素的Set。也就是说SortedSet是一个排序的Set List：是一个有序的集合，可以包含重复的元素。提供了按索引访问的方式。需要注意的是，这个有序并不是指的排序，它指的是在List当中元素是按照一定的次序摆放的，各个元素之间的位置是很重要的。

Java ConcurrentModificationException when using list.remove()

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问题 I've got a method called removeSup which is supposed to remove an object Supplement from a list of supplements. this is the code for the method: private static void removeSup(Supplement supToRemove, List<Supplement> listToRemoveFrom) { Iterator<Supplement> iterator = listToRemoveFrom.iterator(); while(iterator.hasNext()){ if(iterator.next().equals(supToRemove)){ iterator.remove(); } } } there is a class called magazine which defines the list of supplements. public class Magazine { private

multidimensional associative array in C#

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问题 I am trying to find something where I can have a key/value list that contains a key/value list, so it would look something like this: String Item 1 +- key1 -> Object +- key2 -> Object String Item 2 +- key1 -> Object +- key2 -> Object +- key3 -> Object +- key4 -> Object String Item 3 +- key1 -> Object In php It would look like this: array( "String Item 1" => array( "key1" => Object, "key2" => Object ), "String Item 2" => array( "key1" => Object, "key2" => Object, "key3" => Object, "key4" =>

Passing ArrayList value to a Intent.putExtra for Intent.ACTION_SEND

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问题 How to pass arraylist value (samplename, samplequote ) to the intent.putExtra.. for sharing the text.. In MainActivity.java list = new ArrayList<>(); //loading list view item with this function loadRecyclerViewItem(); } private void loadRecyclerViewItem() { list.add(new MyQuote("sample name","sample quote")); In MyRecyclerViewAdapter.java public void onBindViewHolder(final MyRecycleViewAdapter.ViewHolder myholder, int position) { final MyQuote myQuote = myQuoteList.get(position); myholder.tv

Passing ArrayList value to a Intent.putExtra for Intent.ACTION_SEND

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ArrayAdapter, ListView, creating and updating contents

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问题 I posting this again, trying to make the question/problem clearer: ListView lv; List<Item> items; Localstorage ls; RemoteStorage rs; ItemArrayAdapter adapter; ... getShoppingList(); // <--- this method populates the items ArrayList adapter = new ItemArrayAdapter(getApplicationContext(), R.layout.item_listitem, items); // <--- Create an ArrayAdapter and insert the // ArrayList... lv.setAdapter(adapter); The code so far populates the ArrayList items, creates an adapter and adds items to this,

How to use insert data from ArrayList<HashMap<String, String>> into a list view in Android Studio

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问题 I am working on a project that gets queries from a database on a remote server. The SQL side of it gets information from two separate tables, combines them and sends a JSON encoded string back me. I then parse the string and create an ArrayList with a HashMap of String, String to hold the data. All of this works just fine. There are 108 entries and all the related variables show this. My problem arises when I try and put the final ArrayList HashMap into a listView. I have created a custom