I have a problem that I want to set and get an ArrayList from setter and getter methods of android. But I am new to android and Java and don't know how to do that? Can anyone help me regarding this problem?
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7 Answers
Example -
import java.util.ArrayList;
import java.util.List;
public class Test {
List<String> list = null;
public List<String> getList() {
return list;
}
public void setList(List<String> list) {
this.list = list;
}
public static void main(String[] args) {
Test test = new Test();
List<String> sample = new ArrayList<String>();
sample.add("element 1");
test.setList(sample);
List<String> sample1 = test.getList();
}
}
Comments
For better Encapsulation / OO design I would do following
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class TestListGetterSetter {
List<String> list = new ArrayList<>();
//Return copy of the list
public List<String> getList() {
return new ArrayList<>(list);
}
// Copy source list into destination list
public void setList(List<String> listToBeSet) {
if (listToBeSet != null)
this.list.addAll(listToBeSet);
}
public static void main(String[] args) {
TestListGetterSetter testListGetterSetter = new TestListGetterSetter();
List<String> clientList = new ArrayList<>(Arrays.asList("foo", "bar", "HiHa"));
testListGetterSetter.setList(clientList);
System.out.println("TestListGetterSetter.list before clientList modification = " + testListGetterSetter.getList());
//Now you can change "clientList" without affecting testListGetterSetter object
clientList.add("1");
System.out.println("clientList modified List = " + clientList);
System.out.println("TestListGetterSetter.list after clientList modification = " + testListGetterSetter.getList());
}
}
1 Comment
Kuldeep Jain
Correct me if I am wrong but this does not sound right in all cases, because sometimes the user of this api may want to get the list using
getList() and add some elements to it. What do you think? ArrayList<String> arrList = new ArrayList<String>();
public ArrayList<String> getArrList() {
return arrList;
}
public void setArrList(ArrayList<String> arrList) {
this.arrList = arrList;
}
Comments
Generally getter and setter methods are for assign variable and get variables value from that
There is not any difference of getter and setter methods for arraylist or for int of a class
ArrayList<String> arrList;
public ArrayList<String> getArrList() {
return arrList;
}
public void setArrList(ArrayList<String> arrList) {
this.arrList = arrList;
}
Same for Int
int id;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
Comments
I am not familiar with android. But in JAVA, if you want to use set and get method, you need to declare the List first.
private List arrayList = new ArrayList();
public List getArrayList() {
return arrayList;
}
public void setArrayList(List arrayList) {
this.arrayList = arrayList;
}
2 Comments
Lalit Poptani
I haven't see this kind of declaration....private List arrayList = new arrayList;
Lalit Poptani
Still missing buddy checkout my answer how it should be.
please try this
public static ArrayList<books> al = new ArrayList<books>();
books book=new books(id,name,type);
book1 b1=new book1(id,name,type);
al.add(book);
al.add(book1); //error at book1
2 Comments
user6497465
book1 is same class using same pakage .
user6497465
I want to acces both with one one array list object
Try these
public ArrayList getArrayList() {
return arraylist;
}
public void setArrayList(ArrayList arraylist) {
this.arraylist = arraylist;
}
3 Comments
Ilya Saunkin
your setter definitely doesn't do what it's intended to, right?
Rahul Choudhary
@LalitPoptani Buddy it is understood that he has a member variable. Why would you be writing a getter/setter for otherwise.
Lalit Poptani
@RahulChoudhary OMG, public void setArrayList(ArrayList arraylist) { this.arraylist = arraylist; } is this the way you set and arrayList? instead of changing your answer you are bouncing back on me.