Pass on Layout IDs dynamically

Question

I want to implement a 'favorite list' and let's assume that I have got an empty layout. At onCreate() there is super.onCreate(savedInstanceState); setContentView(R.layout.main); and then I open a database with my favorite animals, load a few things and add dynamically buttons to the layout.

The database schema is this:
CREATE TABLE animals(_id INTEGER PRIMARY KEY, name TEXT NOT NULL, layout TEXT NOT NULL)

and in the database there is:

_id - - - - - - - - name - - - - - - - - - layout
1 - - - - - - - - -- cat - - - - - - - - -- R.layout.cat
2 - - - - - - - - -- dog - - - - - - - - -- R.layout.dog
3 - - - - - - - - -- turtle - - - - - - - - R.layout.turtle

Of course the layouts/xml-files (R.layout.cat, R.layout.dog, R.layout.turtle) exist.

So then you see three buttons saying cat, dog and turtle. In the OnClickListener there is the following:

    Intent intent = new Intent(MyFavorites.this, Animal.class);  
    Log.d ("onClick", button.getmyLayout());  
    // Shows either R.layout.cat, R.layout.dog or R.layout.turtle 
    // depending on what button was pressed. This works fine.
    intent.putExtra("myLayout", button.getmyLayout());    
    // closes the database
    myDbHelper.close();
    startActivity(intent);

The Animal.classcan show all animal-xml-files because they all have the same functionality. This is why the layout is always passed on to the same class!

The Animal.class:

    @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            final int myLayout = getIntent().getIntExtra("myLayout", R.layout.main);
            setContentView(myLayout);
        }

Now here is the problem. I pass on a String and not an Integer and in the log cat there is:

Key myLayout expected Integer but value was a java.lang.String. The default value 2130903044 was returned.

The default value is R.layout.main which you find in the autogenerated R.class as a hex number and in decimal it is 2130903044. So I do understand the error message. But I cannot think of another way to solve this problem. I was thinking about getters and setters in the R.class but of course they will be deleted at the next build.

Answer 1

Please see this question, I think it is what you need. Basically you can get the resource by using a string ...

int i = this.getResources().getIdentifier("cat", "layout", this.getPackageName());

And here is the documentation for getIdentifier().

Answer 2

If your amount of layouts is finite and reasonable (you define reasonable %) I would propose to use just static map:

static Map<String,Integer> layouts = new HashMap<String,Integer>()
static {
   layouts.put("cat",R.layout.cat);
   ...
   layouts.put("unicorn",R.layout.unicorn);
}

This way you will get compile time safety, and it would be faster at the runtime.