Android学习之创建中间缓存文件，处理文件名重复问题

	/**
	 * 创建中间缓存文件
	 * 
	 * @param fileName
	 * @return file
	 */
	private File createFile(String fileName){
		String hostName = fileName;
		String extName = "";
		int pos = fileName.lastIndexOf(".");
		if (pos != -1) {
			hostName = fileName.substring(0, pos);
			extName = fileName.substring(pos+1);
		}
		
		File tempFile = new File(getDir(), fileName);
		int i=1;
		while (tempFile.exists()) {
			if (extName == null || extName.length() == 0) {
				fileName = MessageFormat.format("{0}({1})", hostName, i++);
			}
			else {
				fileName = MessageFormat.format("{0}({1}).{2}", hostName, i++, extName);
			}
			tempFile =new File(getDir(), fileName);
		}
		
		return tempFile;
	}