switch case statement error case expressions must be constant expression

Question

My switch-case statement works perfectly fine yesterday  But when I run the code earlier this morning eclipse gave me an error underlining the case statements in color red and says  case expressions must be constant expression  it is constant I don t know what happened  Here s my code below   public void onClick View src                switch src getId              case R id playbtn              checkwificonnection                break           case R id stopbtn              Log d TAG   onClick  stopping srvice                Playbutton setImageResource R drawable playbtn1               Playbutton setVisibility 0     visible             Stopbutton setVisibility 4     invisible             stopService new Intent RakistaRadio this myservice class                clearstatusbar                timer cancel                Title setText                   Artist setText                   break           case R id btnmenu              openOptionsMenu                break                    All R id int are all underlined in red

User · Answer

Unchecking  Is Library  in the project Properties worked for me

User · Answer

Simply declare your variable to final

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Simple solution for this problem is    Click on the switch and then press CTL 1  It will change your switch to if-else block statement  and will resolve your problem

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How about this other solution to keep the nice switch instead of an if-else   private enum LayoutElement       NONE -1       PLAY BUTTON R id playbtn       STOP BUTTON R id stopbtn       MENU BUTTON R id btnmenu        private static class             static SparseArray lt LayoutElement gt  elements   new SparseArray lt LayoutElement gt                LayoutElement int id              elements put id  this              public static LayoutElement from View view            return   elements get view getId    NONE              So in your code you can do this   public void onClick View src        switch LayoutElement from src         case PLAY BUTTTON          checkwificonnection            break       case STOP BUTTON          Log d TAG   onClick  stopping srvice            Playbutton setImageResource R drawable playbtn1           Playbutton setVisibility 0     visible         Stopbutton setVisibility 4     invisible         stopService new Intent RakistaRadio this myservice class            clearstatusbar            timer cancel            Title setText               Artist setText               break       case MENU BUTTON          openOptionsMenu            break            Enums are static so this will have very limited impact  The only window for concern would be the double lookup involved  first on the internal SparseArray and later on the switch table   That said  this enum can also be utilised to fetch the items in a fluent manner  if needed by keeping a reference to the id    but that s a story for some other time

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It was throwing me this error when I using switch in a function with variables declared in my class   private void ShowCalendar final Activity context  Point p  int type         switch  type            case type cat              break           case type region              break           case type city              break           default                sth             break            The problem was solved when I declared final to the variables in the start of the class   final int type cat 1  type region 2  type city 3

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In a regular Android project  constants in the resource R class are declared like this   public static final int main 0x7f030004    However  as of ADT 14  in a library project  they will be declared like this   public static int main 0x7f030004    In other words  the constants are not final in a library project  Therefore your code would no longer compile   The solution for this is simple  Convert the switch statement into an if-else statement   public void onClick View src        int id   src getId        if  id    R id playbtn           checkwificonnection          else if  id    R id stopbtn           Log d TAG   onClick  stopping srvice            Playbutton setImageResource R drawable playbtn1           Playbutton setVisibility 0     visible         Stopbutton setVisibility 4     invisible         stopService new Intent RakistaRadio this myservice class            clearstatusbar            timer cancel            Title setText               Artist setText             else if  id    R id btnmenu           openOptionsMenu              http   tools android com tips non-constant-fields  You can quickly convert a switch statement to an if-else statement using the following   In Eclipse Move your cursor to the switch keyword and press Ctrl   1 then select      Convert  switch  to  if-else     In Android Studio Move your cursor to the switch keyword and press Alt   Enter then select      Replace  switch  with  if

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I would like to mention that  I came across the same situation when I tried adding a library into my project  All of a sudden all switch statements started to show errors   Now I tried to remove the library which I added  even then it did not work  how ever  when I cleaned the project  all the errors just went off

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Solution can be done be this way    Just assign the value to Integer Make variable to final   Example   public static final int cameraRequestCode   999    Hope this will help you

User · Answer

R id    since ADT 14 are not more declared as final static int so you can not use in switch case construct  You could use if else clause instead

[java] switch case statement error: case expressions must be constant expression

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