First I'll state that I'm much more familiar with enums in C# and it seems like enums in java is a quite mess.
As you can see, I'm trying to use a switch statement @ enums in my next example but I always get an error no matter what I'm doing.
The error I receive is:
The qualified case label
SomeClass.AnotherClass.MyEnum.VALUE_A
must be replaced with the unqualified enum constantVALUE_A
The thing is I quite understand the error but I can't just write the VALUE_A since the enum is located in another sub-class. Is there a way to solve this problem? And why is it happening in Java?
//Main Class
public class SomeClass {
//Sub-Class
public static class AnotherClass {
public enum MyEnum {
VALUE_A, VALUE_B
}
public MyEnum myEnum;
}
public void someMethod() {
MyEnum enumExample //...
switch (enumExample) {
case AnotherClass.MyEnum.VALUE_A: { <-- error on this line
//..
break;
}
}
}
}
This question is related to
java
enums
switch-statement
Write someMethod()
in this way:
public void someMethod() {
SomeClass.AnotherClass.MyEnum enumExample = SomeClass.AnotherClass.MyEnum.VALUE_A;
switch (enumExample) {
case VALUE_A:
break;
}
}
In switch statement you must use the constant name only.
This is how I am using it. And it is working fantastically -
public enum Button {
REPORT_ISSUES(0),
CANCEL_ORDER(1),
RETURN_ORDER(2);
private int value;
Button(int value) {
this.value = value;
}
public int getValue() {
return value;
}
}
And the switch-case
as shown below
@Override
public void onClick(MyOrderDetailDelgate.Button button, int position) {
switch (button) {
case REPORT_ISSUES: {
break;
}
case CANCEL_ORDER: {
break;
}
case RETURN_ORDER: {
break;
}
}
}
Wrong:
case AnotherClass.MyEnum.VALUE_A
Right:
case VALUE_A:
Java infers automatically the type of the elements in case
, so the labels must be unqualified.
int i;
switch(i) {
case 5: // <- integer is expected
}
MyEnum e;
switch (e) {
case VALUE_A: // <- an element of the enumeration is expected
}
this should do:
//Main Class
public class SomeClass {
//Sub-Class
public static class AnotherClass {
public enum MyEnum {
VALUE_A, VALUE_B
}
public MyEnum myEnum;
}
public void someMethod() {
AnotherClass.MyEnum enumExample = AnotherClass.MyEnum.VALUE_A; //...
switch (enumExample) {
case VALUE_A: { //<-- error on this line
//..
break;
}
}
}
}
Source: Stackoverflow.com