Retrieves a resource id dynamically, via reflection.

Description

Demo Code


//package com.java2s;

import java.lang.reflect.Field;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import android.util.Log;

public class Main {
    /** Cache of resources ids, for speed */
    private static Map<Class<?>, Map<String, Integer>> sIdentifierCache = new ConcurrentHashMap<Class<?>, Map<String, Integer>>();

    /**//from ww  w . j ava  2s .c om
     * Retrieves a resource id dynamically, via reflection.  It's much faster
     * than Resources.getIdentifier(), however it only allows you to get
     * identifiers from your own package. 
     * 
     * Note that this method is still slower than retrieving resources
     * directly (e.g., R.drawable.MyResource) - it should only be used
     * when dynamically retrieving ids.
     * 
     * Originally sourced from https://github.com/dlew/android-utils/
     * 
     * @param type the type of resource (e.g. R.drawable.class, R.layout.class, etc.)
     * @param name the name of the resource
     * @return the resource id, or 0 if not found
     */
    public static int getIdentifier(Class<?> type, String name) {
        // See if the cache already contains this identifier
        Map<String, Integer> typeCache;
        if (!sIdentifierCache.containsKey(type)) {
            typeCache = new ConcurrentHashMap<String, Integer>();
            sIdentifierCache.put(type, typeCache);
        } else {
            typeCache = sIdentifierCache.get(type);
        }

        if (typeCache.containsKey(name)) {
            return typeCache.get(name);
        }

        // Retrieve the identifier
        try {
            Field field = type.getField(name);
            int resId = field.getInt(null);

            if (resId != 0) {
                typeCache.put(name, resId);
            }

            return resId;
        } catch (Exception e) {
            Log.e("JodaTimeAndroid", "Failed to retrieve identifier: type="
                    + type + " name=" + name, e);
            return 0;
        }
    }
}

Retrieves a resource id dynamically, via reflection. - Android App

Description

Demo Code

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