【转】String自动换行

               String 	messageTextC =  autoCut(messageTextC,50);	

///////////////////////////////////////////////	
                String newString = "";
		char[] arr = str.toCharArray();
		int txtLen = 0;// 文本长度
		int charCount = 0;// 字符计数器
		int startIndex = 0;// 开始索引
		int endIndex = 0;// 结束索引
		ArrayList result = new ArrayList();// 字符串数组
		int j = 0;
		for (int i = 0; i < arr.length; i++) {
			if (isChinese(arr[i])) {
				txtLen += 2;
				charCount++;
			} else {
				txtLen++;
				charCount++;
			}
			if (txtLen == charLen) {
				startIndex = endIndex;
				endIndex = startIndex + charCount;
				charCount = 0;
				txtLen = 0;
				result.add(j++, str.substring(startIndex, endIndex));
			} else if (txtLen == charLen + 1) {
				startIndex = endIndex;
				endIndex = startIndex + charCount - 1;
				charCount = 0;
				txtLen = 0;
				result.add(j++, str.substring(startIndex, endIndex));
			}
		}
		if (endIndex < str.length()) {
			startIndex = endIndex;
			result.add(j, str.substring(startIndex, str.length()));
		}
		result.trimToSize();
		Iterator itr = result.iterator();
		while (itr.hasNext()) {
			newString = newString + itr.next() + "\n";
		}
		return newString;

 

 

	private boolean isChinese(char c) {
		Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
		if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
				|| ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
				|| ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
				|| ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
				|| ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
				|| ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS)
			return true;
		return false;
	} 	}