Java 如何在数组中存储多种数据类型？
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How to store multiple datatypes in an array?
提问by johnsonjp34
I'm looking for something like an Array, but it needs to store multiple data types. The Oracle Java tutorials says, "An array is a container object that holds a fixed number of values of a single type." So if I can't use an array for multiple types, what do I use?
我正在寻找类似数组的东西，但它需要存储多种数据类型。Oracle Java 教程说：“数组是一个容器对象，它包含固定数量的单一类型的值。” 因此，如果我不能将数组用于多种类型，我该使用什么？
I've got this code that only adds one marker to the map at a time because it writes over my lat and long values each loop and only passes the last to the onPostExecute. So I will need something like an array to pass multiple forms of contact info. ie I'm pulling the location from each JSON string, but I need to pull and pass the name & phone number too to the UI from this background thread.
我有这段代码一次只向地图添加一个标记，因为它在每个循环中写入我的经纬度值，并且只将最后一个传递给 onPostExecute。所以我需要类似数组的东西来传递多种形式的联系信息。即我从每个 JSON 字符串中提取位置，但我也需要从这个后台线程中提取并传递姓名和电话号码到 UI。
try {
String apples = endpoint.listContactInfo().execute().toString();
JSONObject jObject = new JSONObject(apples);
JSONArray jsonArr = jObject.getJSONArray("items");
for(int i =0 ; i<jsonArr.length() ;i++ ){
JSONObject jsonObj1 = jsonArr.getJSONObject(i);
// Storing each json item in variable
String id = jsonObj1.getString(TAG_ID);
String nameFirst1 = jsonObj1.getString(TAG_FIRSTNAME);
String nameLast1 = jsonObj1.getString(TAG_LASTNAME);
String emailAddress1 = jsonObj1.getString(TAG_EMAIL);
String streetAddress1 = jsonObj1.getString(TAG_ADDRESS);
String phone1 = jsonObj1.getString(TAG_PHONE);
//test to see if made it to string
Log.d("YOUR_TAG", "First Name: " + nameFirst1 + " Last Name: " + nameLast1);
address = coder.getFromLocationName(streetAddress1,5);
Address location1 = address.get(0);
// SET LAT LNG VALUES FOR MARKER POINT
lati = location1.getLatitude();
longi = location1.getLongitude();
Log.d("Location", "Location:" + lati + " " + longi);
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return (long) 0;
}
// ADD MARKER TO MAP UI
protected void onPostExecute(Long result) {
mMap.addMarker(new MarkerOptions()
.position(new LatLng(lati, longi))
.title("Hello world"));
}
采纳答案by Philipp Jahoda
You can create an array of your Custom-Class.
您可以创建自定义类的数组。
public class YourCustomClass {
String id;
String name;
double longitude;
// and many more fields ...
public YourCustomClass() { // constructor
}
public void setID(String id) {
this.id = id;
}
public String getID() {
return id;
}
// and many more getter and setter methods ...
}
Inside your custom-class you can have as many fields as you want where you can store your data, and then use it like that:
在您的自定义类中，您可以拥有任意数量的字段，您可以在其中存储数据，然后像这样使用它：
// with array
YourCustomClass [] array = new YourCustomClass[10];
array[0] = new YourCustomClass();
array[0].setID("yourid");
String id = array[0].getID();
// with arraylist
ArrayList<YourCustomClass> arraylist = new ArrayList<YourCustomClass>();
arraylist.add(new YourCustomObject());
arraylist.get(0).setID("yourid");
String id = arraylist.get(0).getID();
You can also let the AsyncTasks doInBackground(...) method return your Custom-class:
您还可以让 AsyncTasks doInBackground(...) 方法返回您的自定义类：
protected void onPostExecute(YourCustomClass result) {
// do stuff...
}
Or an array:
或者一个数组：
protected void onPostExecute(YourCustomClass [] result) {
// do stuff...
}
Or a ArrayList:
或者一个 ArrayList：
protected void onPostExecute(ArrayList<YourCustomClass> result) {
// do stuff...
}
Edit:Of course, you can also make a ArrayListof your custom object.
编辑：当然，您也可以创建自定义对象的ArrayList。
回答by user2748689
You can use an ArrayList.
您可以使用一个ArrayList.
ArrayList<Object> listOfObjects = new ArrayList<Object>();
And then add items to it.
然后向其中添加项目。
listOfObjects.add("1");
listOfObjects.add(someObject);
Or create your own object that encapsulates all the field that you require like
或者创建您自己的对象来封装您需要的所有字段
public class LocationData {
private double lat;
private double longitude;
public LocationData(double lat, double longitude) {
this.lat = lat;
this.longitude = longitude;
}
//getters
//setters
}
and then add your lat/long pairs to an ArrayListof type LocationData
然后将您的纬度/经度对添加到ArrayList类型LocationData
ArrayList<LocationData> listOfObjects = new ArrayList<LocationData>();
listOfObjects.add(new LocationData(lat, longitude));
回答by mike
You should consider the use of the typesafe heterogeneous container pattern.
您应该考虑使用类型安全的异构容器模式。
There the data is stored in a Map<Key<?>, Object>and access to the map is hidden behind generic methods, that automatically cast the return value.
数据存储在 a 中Map<Key<?>, Object>，对地图的访问隐藏在通用方法后面，这些方法会自动转换返回值。
public <T> T getObjectByKey(Key<T> key)
return (T) map.get(key);
The same for put.
对于put.
