DexClassLoader一次失败的尝试

本次代码主要想解决DexClassLoader出现ClassNotFound问题，实际上没有解决。但毕竟是自己第一次写的ClassLoader。这里记录一下。

/**
 * DexClassLoader may cause ClassNotFound because of caching wrong DexInfo in
 * some cases
 * 
 * To avoid the caching problem. This class will try to reCreate DexClassLoader
 * and call loadClass again to solve the issue.
 * 
 * @author zhenhuachen
 */
final class RetryDexClassLoader extends DexClassLoader {

	private String mDexPath;

	private String mOptimizedDirectory;

	private String mLibraryPath;

	private ClassLoader mParent;

	private DexClassLoader mSecondRecoveryClassLoader;
	
	private ArrayList<ClassLoader> mCreatedClassLoaderList = new ArrayList<ClassLoader>();

	/**
	 * map of class.
	 */
	private final ConcurrentHashMap<String, Class<?>> mClassMap = new ConcurrentHashMap<String, Class<?>>();

	public RetryDexClassLoader(String dexPath, String optimizedDirectory,
			String libraryPath, ClassLoader parent) {
		super(dexPath, optimizedDirectory, libraryPath, parent);
		mDexPath = dexPath;
		mOptimizedDirectory = optimizedDirectory;
		mLibraryPath = libraryPath;
		mParent = parent;
		mCreatedClassLoaderList.add(parent);
	}

	private void createRealClassLoader() {
		MultiParentClassLoader parentLoader = new MultiParentClassLoader();
		parentLoader.addParent(mCreatedClassLoaderList);
		
		mSecondRecoveryClassLoader = new DexClassLoader(mDexPath,
				mOptimizedDirectory, mLibraryPath, parentLoader);
		
		mCreatedClassLoaderList.add(mSecondRecoveryClassLoader);
	}

	@Override
	public Class<?> loadClass(String name) throws ClassNotFoundException {
		Class<?> clazz = mClassMap.get(name);

		if (null != clazz) {
			return clazz;
		}

		try {
			clazz = mParent.loadClass(name);
		} catch (ClassNotFoundException e) {
			try {
				clazz = findClass(name);
			} catch (ClassNotFoundException e1) {
				createRealClassLoader();
				clazz = mSecondRecoveryClassLoader.loadClass(name);
			}
		}

		if (null == clazz) {
			throw new ClassNotFoundException("Didn't find class \"" + name);
		} else {
			mClassMap.put(name, clazz);
		}

		return clazz;
	}
}


final class MultiParentClassLoader extends ClassLoader{

	private ArrayList<ClassLoader> mParentLoaderList = new ArrayList<ClassLoader>();
	
	public MultiParentClassLoader() {
	}

	@Override
	public Class<?> loadClass(String className) throws ClassNotFoundException {
		Class<?> clazz = null;
		
		for (ClassLoader loader : mParentLoaderList) {
			try{
				clazz = loader.loadClass(className);
			} catch(ClassNotFoundException e) {
				Log.d("MultiParentClassLoader", "loadClass");
			}
		}
		
		if (null != clazz) {
			Log.d("MultiParentClassLoader", "loadClass found in mParentLoaderList");
		}
		return clazz;
	}
	
	public void addParent(ClassLoader loader) {
		mParentLoaderList.add(loader);
	}
	
	public void addParent(ArrayList<ClassLoader> loaderList) {
		mParentLoaderList.addAll(loaderList);
	}
	
}