[TinyTut] - Get ResourceName by its ID

plusminus · by **plusminus** » Sat Jan 12, 2008 5:30 pm

What you learn: You will learn how get Name of a Resource if you only know the ID. This Tutorial uses the Java Reflection API (no need for you to code on your own

).

Difficulty: 1.5 of 5

Questions/Problems: Simply post below...

Description: I was not aware of a function returning the name of a Resource (what is the filename without the file-ending) of a known resource (knowing only its ID), so I coded one myself...
Example-Call:

Syntax: [ Download ] [ Hide ]

Using java Syntax Highlighting

// Example-Call:
String resName = getResourceNameFromClassByID(R.drawable.class, R.drawable.icon);
// resName would be 'icon'.
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The Source:
Using the Java Reflection API this was not hard to do.

Syntax: [ Download ] [ Hide ]

Using java Syntax Highlighting

        /**
         * Determines the Name of a Resource, 
         * by passing the <code>R.xyz.class</code> and 
         * the <code>resourceID</code> of the class to it.
         * @param aClass : like <code>R.drawable.class</code>
         * @param resourceID : like <code>R.drawable.icon</code>
         * @throws IllegalArgumentException if field is not found.
         * @throws NullPointerException if <code>aClass</code>-Parameter is null.
         * <br><br>
         * <b>Example-Call:</b><br> 
         * <code>String resName = getResourceNameFromClassByID(R.drawable.class, R.drawable.icon);</code><br>
         * Then <code>resName</code> would be '<b>icon</b>'.*/
        public String getResourceNameFromClassByID(Class<?> aClass, int resourceID) 
                                                throws IllegalArgumentException{
                /* Get all Fields from the class passed. */
                Field[] drawableFields = aClass.getFields();
                
                /* Loop through all Fields. */
                for(Field f : drawableFields){
                        try {
                                /* All fields within the subclasses of R 
                                 * are Integers, so we need no type-check here. */
                                
                                /* Compare to the resourceID we are searching. */
                                if (resourceID == f.getInt(null))
                                        return f.getName(); // Return the name.
                        } catch (Exception e) {
                                e.printStackTrace();
                        }
                }
                /* Throw Exception if nothing was found*/
                throw new IllegalArgumentException();
        }
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