保存图片至SD卡，获取SD卡图片，判断sdcard图片是存在,计算sdcard上的剩余空间

/***
* 保存图片至SD卡
*
* @param bm
* @param url
* @param quantity
*/
private static int FREE_SD_SPACE_NEEDED_TO_CACHE = 1;
private static int MB = 1024 * 1024;
public final static String DIR = "/sdcard/hypers";

public static void saveBmpToSd(Bitmap bm, String url, int quantity) {
// 判断sdcard上的空间
if (FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
return;
}
if (!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()))
return;
String filename = url;
// 目录不存在就创建
File dirPath = new File(DIR);
if (!dirPath.exists()) {
dirPath.mkdirs();
}

File file = new File(DIR + "/" + filename);
try {
file.createNewFile();
OutputStream outStream = new FileOutputStream(file);
bm.compress(Bitmap.CompressFormat.PNG, quantity, outStream);
outStream.flush();
outStream.close();

} catch (FileNotFoundException e) {

} catch (IOException e) {
e.printStackTrace();
}

}

/***
* 获取SD卡图片
*
* @param url
* @param quantity
* @return
*/
public static Bitmap GetBitmap(String url, int quantity) {
InputStream inputStream = null;
String filename = "";
Bitmap map = null;
URL url_Image = null;
String LOCALURL = "";
if (url == null)
return null;
try {
filename = url;
} catch (Exception err) {
}

LOCALURL = URLEncoder.encode(filename);
if (Exist(DIR + "/" + LOCALURL)) {
map = BitmapFactory.decodeFile(DIR + "/" + LOCALURL);
} else {
try {
url_Image = new URL(url);
inputStream = url_Image.openStream();
map = BitmapFactory.decodeStream(inputStream);
// url = URLEncoder.encode(url, "UTF-8");
if (map != null) {
saveBmpToSd(map, LOCALURL, quantity);
}
inputStream.close();
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
return map;
}

/***
* 判断图片是存在
*
* @param url
* @return
*/
public static boolean Exist(String url) {
File file = new File(DIR + url);
return file.exists();
}

/** * 计算sdcard上的剩余空间 * @return */
private static int freeSpaceOnSd() {
StatFs stat = new StatFs(Environment.getExternalStorageDirectory().getPath());
double sdFreeMB = ((double) stat.getAvailableBlocks() * (double) stat.getBlockSize()) / MB;

return (int) sdFreeMB;
}