android自带的内存memory和第三方外部存储disk管理

/**
* @author intbird@163.com
* @time 20140606
*/
package com.intbird.utils;

import java.io.File;

import com.yilake.store.FileHelper;

import android.graphics.Bitmap;
import android.os.Environment;
import android.util.LruCache;

public class CacheManager {
//单例
private static CacheManager cacheInstance;

//内存缓存大小
private final int MEMO_CACHE_SIZE=((int)(Runtime.getRuntime().maxMemory()/1024));
//文件缓存大小
private final int DISK_CACHE_SIZE=1024*1024*100;
//内存缓存
private LruCache<String,Bitmap> mMemoryCache;
//文件缓存
private DiskLruCache mDiskLruCache;
private String cacheUrl="";

public CacheManager() {
//内存缓存
mMemoryCache=new LruCache<String, Bitmap>(MEMO_CACHE_SIZE){
protected int sizeOf(String key, Bitmap bitmap) {
return bitmap.getByteCount()/1024;
};
};
//文件缓存
setBitmapFileCacheDir(FileHelper.DISK_CACHE_FILEDIR);
}

/**
* 获取单例
* @return
*/
public static CacheManager getInstance() {
if(cacheInstance==null){
cacheInstance=new CacheManager();
}
return cacheInstance;
}

/**
* 设置缓存目录;
* @param cacheDir
*/
public void setBitmapFileCacheDir(String cacheDir){
File cacheFile=	getDiskFileCache(cacheDir);
cacheUrl=cacheFile.getAbsolutePath();
mDiskLruCache=DiskLruCache.openCache(cacheFile, DISK_CACHE_SIZE);
}
/**
* 返回缓存目录路径
* @return
*/
public String getBitmapFileCacheDir(){
return cacheUrl;
}

//通用外部调用
public void addBitmapToCache(String fileUrl, Bitmap bitmap) {
addBitmapToMemory(fileUrl,bitmap);
addBitmapToDisk(fileUrl,bitmap);
}

public Bitmap getBitmapFromCache(String key){
Bitmap bmp=null;
bmp=getBitmapFromMemory(key);
if(bmp==null){
bmp=getBitmapFromDisk(key);
}
return bmp;
}

/**
* 图片加入内存缓存
* @param key
* @param bitmap
*/
private void addBitmapToMemory(String key,Bitmap bitmap){
if(getBitmapFromMemory(key)==null){
mMemoryCache.put(key, bitmap);
}
}
/**
* 获取内存缓存图片
* @param key
* @return
*/
private Bitmap getBitmapFromMemory(String key){
return mMemoryCache.get(key);
}
/**

* 将图片加入文件缓存
* @param key
* @param bitmap
*/
private void addBitmapToDisk(String key,Bitmap bitmap){
if (mDiskLruCache != null && mDiskLruCache.get(key) == null) {
mDiskLruCache.put(key, bitmap);
}
}
/**
* 从文件缓存中获取图片
* @param key
* @return
*/
private Bitmap getBitmapFromDisk(String key){
if (mDiskLruCache != null) {
return mDiskLruCache.get(key);
}
return null;
}

/**
* 获取缓存目录
* @return
*/
public static File getDiskFileCache(String cacheDir){
String cachePath =Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) ||
!Environment.isExternalStorageRemovable() ?
Environment.getExternalStorageDirectory().getPath():
Environment.getDataDirectory().getPath();
File file =new File(cachePath + File.separator + cacheDir);
if(!file.exists()) file.mkdir();
return file;
}
}