Java using enum with switch statement

Question

I ve looked at various Q amp As on SO similar to this question but haven t found a solution   What I have is an enum which represents different ways to view a TV Guide     In the NDroid Application class  static enum guideView       GUIDE VIEW SEVEN DAY      GUIDE VIEW NOW SHOWING      GUIDE VIEW ALL TIMESLOTS        when the user changes the view an event handler receives an int from 0-2 and I d like to do something like this     In an Android Activity onClick DialogInterface dialog  int which  event handler      which  is an int from 0-2 switch  which        case NDroid guideView GUIDE VIEW SEVEN DAY              break      I m used to C  enums and select case statements which would allow something like the above and I know Java does things differently but I just can t make sense of what I need to do   Am I going to have to resort to if statements  There will likely only ever be 3 choices so I could do it but I wondered how it could be done with switch-case in Java   EDIT Sorry I didn t completely expand on the issue as I was looking at it as being a generic Java issue  I ve added to the question to explain a bit further   There isn t anything that s Android specific which is why I didn t tag it as Android but the enum is defined in the Application class and the code where I wan t the switch is in an Activity  The enum is static as I need to access it from multiple Activities

User · Accepted Answer

The part you re missing is converting from the integer to the type-safe enum   Java will not do it automatically   There s a couple of ways you can go about this    Use a list of static final ints rather than a type-safe enum and switch on the int value you receive  this is the pre-Java 5 approach  Switch on either a specified id value  as described by heneryville  or the ordinal value of the enum values  i e  guideView GUIDE VIEW SEVEN DAY ordinal   Determine the enum value represented by the int value and then switch on the enum value   enum GuideView       SEVEN DAY      NOW SHOWING      ALL TIMESLOTS       Working on the assumption that your int value is     the ordinal value of the items in your enum public void onClick DialogInterface dialog  int which           do your own bounds checking     GuideView whichView   GuideView values   which       switch  whichView            case SEVEN DAY                              break          case NOW SHOWING                              break            You may find it more helpful   less error prone to write a custom valueOf implementation that takes your integer values as an argument to resolve the appropriate enum value and lets you centralize your bounds checking

User · Answer

Short associative function example   public String getIcon TipoNotificacao tipo        switch  tipo           case Comentou   return  fa fa-comments           case ConviteEnviou   return  icon-envelope           case ConviteAceitou   return  fa fa-bolt           default  return               Like  Dhanushka said  omit the qualifier inside  switch  is the key

User · Answer

This should work in the way that you describe  What error are you getting  If you could pastebin your code that would help   http   download oracle com javase tutorial java javaOO enum html  EDIT  Are you sure you want to define a static enum  That doesn t sound right to me  An enum is much like any other object  If your code compiles and runs but gives incorrect results  this would probably be why

User · Answer

I am doing it like   public enum State          Retrieving     the MediaRetriever is retrieving music        Stopped     media player is stopped and not prepared to play     Preparing     media player is preparing        Playing     playback active  media player ready     but the media player                    may actually be                    paused in this state if we don t have audio focus  But we                    stay in this state                    so that we know we have to resume playback once we get                    focus back      Paused     playback paused  media player ready          public final static State   vals   State values     copy the values    calling values   clones the array      public State getState             return mState         And use in Switch Statement  switch  mService getState      case Stopped  case Paused       playPause setBackgroundResource R drawable selplay       break   case Preparing  case Playing       playPause setBackgroundResource R drawable selpause       break

User · Answer

enumerations accessing is very simple in switch case  private TYPE currentView     declaration of enum  public enum TYPE           FIRST  SECOND  THIRD           handling in switch case switch  getCurrentView                      case FIRST              break          case SECOND              break          case THIRD              break               getter and setter of the enum public void setCurrentView TYPE currentView            this currentView   currentView             public TYPE getCurrentView             return currentView           usage of setting the enum  setCurrentView TYPE FIRST    avoid the accessing of TYPE FIRST ordinal   it is not recommended always

User · Answer

If whichView is an object of the GuideView Enum  following works well  Please note that there is no qualifier for the constant after case   switch  whichView        case SEVEN DAY                      break      case NOW SHOWING                      break

User · Answer

The enums should not be qualified within the case label like what you have NDroid guideView GUIDE VIEW SEVEN DAY  instead you should remove the qualification and use GUIDE VIEW SEVEN DAY

User · Answer

I like a few usages of Java enum     name   allows you to fetch the enum name in String   ordinal   allow you to get the integer value  0-based  You can attach other value parameters with each enum  and  of course  switch enabled    enum with value parameters       enum StateEnum           UNDEFINED POLL    1   1000L        4   1000L           SUPPORT POLL      1   1000L        5   1000L           FAST POLL         2   1000L   4   60   1000L           NO POLL           1   1000L        6   1000L                        switch example   private void queuePoll StateEnum se           debug print se name   if needed     switch  se            case UNDEFINED POLL                              break          case SUPPORT POLL                              break

[java] Java using enum with switch statement

Examples related to java

Examples related to enums

Examples related to switch-statement