I've looked at various Q&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.
This question is related to
java
enums
switch-statement
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;
}
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;
}
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.
I like a few usages of Java enum:
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;
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
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.
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
Source: Stackoverflow.com