package com.wpc.library.util.cache;
|
|
import java.io.File;
|
import java.io.FileNotFoundException;
|
import java.io.FileOutputStream;
|
import java.io.IOException;
|
import java.io.OutputStream;
|
import java.util.Arrays;
|
import java.util.Comparator;
|
|
import android.graphics.Bitmap;
|
import android.graphics.BitmapFactory;
|
import android.os.Environment;
|
import android.os.StatFs;
|
import android.util.Log;
|
|
public class ImageFileCache {
|
private static final String CACHDIR = "ImgCach";
|
private static final String WHOLESALE_CONV = ".cach";
|
|
private static final int MB = 1024 * 1024;
|
private static final int CACHE_SIZE = 10;
|
private static final int FREE_SD_SPACE_NEEDED_TO_CACHE = 10;
|
|
public ImageFileCache() {
|
// 清理文件缓存
|
removeCache(getDirectory());
|
}
|
|
/** 从缓存中获取图片 **/
|
public Bitmap getImage(final String url) {
|
final String path = getDirectory() + "/" + convertUrlToFileName(url);
|
File file = new File(path);
|
if (file.exists()) {
|
Bitmap bmp = BitmapFactory.decodeFile(path);
|
if (bmp == null) {
|
file.delete();
|
} else {
|
updateFileTime(path);
|
return bmp;
|
}
|
}
|
return null;
|
}
|
|
/** 将图片存入文件缓存 **/
|
public void saveBitmap(Bitmap bm, String url) {
|
if (bm == null) {
|
return;
|
}
|
// 判断sdcard上的空间
|
if (FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
|
// SD空间不足
|
return;
|
}
|
String filename = convertUrlToFileName(url);
|
String dir = getDirectory();
|
File dirFile = new File(dir);
|
if (!dirFile.exists()) {
|
dirFile.mkdirs();
|
}
|
File file = new File(dir, filename);
|
try {
|
file.createNewFile();
|
OutputStream outStream = new FileOutputStream(file);
|
bm.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
|
outStream.flush();
|
outStream.close();
|
} catch (FileNotFoundException e) {
|
Log.w("ImageFileCache", "FileNotFoundException");
|
} catch (IOException e) {
|
e.printStackTrace();
|
Log.w("ImageFileCache", "IOException");
|
}
|
}
|
|
/**
|
* 计算存储目录下的文件大小，
|
* 当文件总大小大于规定的CACHE_SIZE或者sdcard剩余空间小于FREE_SD_SPACE_NEEDED_TO_CACHE的规定
|
* 那么删除40%最近没有被使用的文件
|
*/
|
private boolean removeCache(String dirPath) {
|
File dir = new File(dirPath);
|
File[] files = dir.listFiles();
|
if (files == null) {
|
return true;
|
}
|
if (!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
|
return false;
|
}
|
|
int dirSize = 0;
|
for (int i = 0; i < files.length; i++) {
|
if (files[i].getName().contains(WHOLESALE_CONV)) {
|
dirSize += files[i].length();
|
}
|
}
|
|
if (dirSize > CACHE_SIZE * MB
|
|| FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
|
int removeFactor = (int) ((0.4 * files.length) + 1);
|
Arrays.sort(files, new FileLastModifSort());
|
for (int i = 0; i < removeFactor; i++) {
|
if (files[i].getName().contains(WHOLESALE_CONV)) {
|
files[i].delete();
|
}
|
}
|
}
|
|
return freeSpaceOnSd() > CACHE_SIZE;
|
|
}
|
|
/** 修改文件的最后修改时间 **/
|
public void updateFileTime(String path) {
|
File file = new File(path);
|
long newModifiedTime = System.currentTimeMillis();
|
file.setLastModified(newModifiedTime);
|
}
|
|
/** 计算sdcard上的剩余空间 **/
|
private int freeSpaceOnSd() {
|
StatFs stat = new StatFs(Environment.getExternalStorageDirectory().getPath());
|
double sdFreeMB = ((double) stat.getAvailableBlocks() * (double) stat.getBlockSize()) / MB;
|
return (int) sdFreeMB;
|
}
|
|
/** 将url转成文件名 **/
|
private String convertUrlToFileName(String url) {
|
String filename = url;
|
filename = filename.replace("http://", "");
|
filename = filename.replace("/", ".");
|
filename = filename.replace(":", ".");
|
return filename + WHOLESALE_CONV;
|
}
|
|
/** 获得缓存目录 **/
|
private String getDirectory() {
|
String dir = getSDPath() + "/" + CACHDIR;
|
return dir;
|
}
|
|
/** 取SD卡路径 **/
|
private String getSDPath() {
|
File sdDir = null;
|
boolean sdCardExist = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); // 判断sd卡是否存在
|
if (sdCardExist) {
|
sdDir = Environment.getExternalStorageDirectory(); // 获取根目录
|
}
|
if (sdDir != null) {
|
return sdDir.toString();
|
} else {
|
return "";
|
}
|
}
|
|
/**
|
* 根据文件的最后修改时间进行排序
|
*/
|
private class FileLastModifSort implements Comparator<File> {
|
public int compare(File arg0, File arg1) {
|
if (arg0.lastModified() > arg1.lastModified()) {
|
return 1;
|
} else if (arg0.lastModified() == arg1.lastModified()) {
|
return 0;
|
} else {
|
return -1;
|
}
|
}
|
}
|
}
|
