public static String getExternalStoragePath() {
 // 获取SdCard状态
 String state = android.os.Environment.getExternalStorageState();
 // 判断SdCard是否存在并且是可用的
 if (android.os.Environment.MEDIA_MOUNTED.equals(state)) {
 if (android.os.Environment.getExternalStorageDirectory().canWrite()) {
   return android.os.Environment.getExternalStorageDirectory().getPath();
 }
 }
 return null;
}
public static long getAvailableStore(String filePath) {
 // 取得sdcard文件路径
 StatFs statFs = new StatFs(filePath);
 // 获取block的SIZE
 long blocSize = statFs.getBlockSize();
 // 获取BLOCK数量
 // long totalBlocks = statFs.getBlockCount();
 // 可使用的Block的数量
 long availaBlock = statFs.getAvailableBlocks();
 // long total = totalBlocks * blocSize;
 long availableSpare = availaBlock * blocSize;
 return availableSpare;
}