计算磁盘可用空间

private long getSpaceByFilePath(String path) {
		StatFs statFs = new StatFs(path);
		long blockSizeLong = statFs.getBlockSizeLong();
		long availableBlocksLong = statFs.getAvailableBlocksLong();

		return blockSizeLong * availableBlocksLong;
	}

传入path，获得空间大小

空间大小=可用区块数*区块大小