FileCacheManager.java

/**
 * @author UFreedom
 * @since 2014 2014-10-6 上午12:10:31
 * @see www.52yummy.com
 * <br>
 * sunfreedom@sina.cn
 * <br>
 * Copyright (C) 2014 UFreedom. All Rights Reserved.
 */

package com.codecomb.infrastructure.cache;

import java.io.File;
import java.io.IOException;

import android.content.Context;
import android.graphics.Bitmap;
import android.util.Log;

import com.codecomb.SettingsManager;
import com.codecomb.utils.BitmapHelper;

public class FileCacheManager {
	
	
	private static final String TAG = "MemoryCache";

	private File cacheDir; // the directory to save images

	/**
	 * Constructor
	 * 
	 * @param context
	 *            The context related to this cache.
	 * */
	public FileCacheManager(Context context) {
		// Find the directory to save cached images
		if (android.os.Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED))
			
			cacheDir = new File(
					android.os.Environment.getExternalStorageDirectory(),
					SettingsManager.getInstance().getUsername());
		else
			cacheDir = context.getCacheDir();
		if (!cacheDir.exists())
			cacheDir.mkdirs();

		Log.d(TAG, "cache dir: " + cacheDir.getAbsolutePath());
	}

	/**
	 * Search the specific image file with a unique key.
	 * 
	 * @param key
	 *            Should be unique.
	 * @return Returns the image file corresponding to the key.
	 * */
	public File getFile(String key) {
		File f = new File(cacheDir, key);
		if (f.exists()) {
			Log.i(TAG, "the file you wanted exists " + f.getAbsolutePath());
			return f;
		} else {
			Log.w(TAG,
					"the file you wanted does not exists: "
							+ f.getAbsolutePath());
		}

		return null;
	}

	/**
	 * Put a bitmap into cache with a unique key.
	 * 
	 * @param key
	 *            Should be unique.
	 * @param value
	 *            A bitmap.
	 * */
	public void put(String key, Bitmap value) {
		File f = new File(cacheDir, key);
		if (!f.exists())
			try {
				f.createNewFile();
			} catch (IOException e) {
				e.printStackTrace();
			}
		// Use the util's function to save the bitmap.
		if (BitmapHelper.saveBitmap(f, value))
			Log.d(TAG, "Save file to sdcard successfully!");
		else
			Log.w(TAG, "Save file to sdcard failed!");

	}

	/**
	 * Clear the cache directory on sdcard.
	 * */
	public void clear() {
		File[] files = cacheDir.listFiles();
		for (File f : files)
			f.delete();
	}
}