Question

I’m wondering how to use enums in Java. I’m working on a recipe application for Android. I have a screen with four tabs in a TabHost and would like to refer to them through named constants, and I believe that it’s best to do it through an enum.

private enum mTab {
    TAB_NAME(0), TAB_INGREDIENT(1), TAB_STEP(2), TAB_MEDIA(3);

    final int numTab;

    private mTab(int num){
        this.numTab = num;
    }

    public int getValue(){
        return this.numTab;
    }

};

Now I’d like to create a different menu for each tab. For example, for TAB_INGREDIENT I’d like a menu option called “Add ingredient”, while for TAB_MEDIA I’d like a menu option called “Add image”.

I’m creating the menus through an onPrepareOptionsMenu(), like so

public boolean onPrepareOptionsMenu(Menu menu) {
    // Clear menu before showing new menu
    menu.clear();

    super.onPrepareOptionsMenu(menu);

    // Create new menu based on current tab
    MenuInflater inflater = getMenuInflater();
    int tab = getTabHost().getCurrentTab();

    switch (tab) {
        ...
            }

    return true;
}

The problem is that I don’t know what to put in the switch statement. More specifically, I don’t know how to compare “tab”, which is an integer corresponding to the currently selected tab, to an enum element.

Answer 1

You can add a method as below in your mTab enum –

public static mTab toMTab(int val) {
    mTab retMTab = null;
    for (mTab tempTab : mTab.values()) {
        if(tempTab.getValue() == val)  {
            retMTab = tempTab;
            break;
        }
    }
    return retMTab;
}

and then in your onPrepareOptionsMenu() you can do like this 0

switch(mTab.toMTab(intVal)) {
  case TAB_NAME:
     ...
     break;
  case TAB_INGREDIENT:
     ..
     ...

}