[移动开发]Android动态识别字符编码

最近碰到一个需求，读取txt文本内容并加载到textview中，但是测试发现当txt文件编码为GBK时会乱码，查阅了很多资料，大多数都是通过判断文件前三字节实现字符编码的识别，但是实际发现读取到的前三字节并没有包含编码信息，直接就是文本内容的前三字节，后续查阅到一个资料，基本思想是在输入流中指定解码方式，然后根据读取时有无报错判断是否是该字符编码，这样一来，通过循环使用不同的字符编码去解码就可以得到正确的字符编码，具体实现如下：

private String getTextFileCharset(String filePath){
        String[] charsets = {"US-ASCII", "UTF-8", "GB2312", "BIG5", "GBK", "GB18030", "UTF-16BE", "UTF-16LE", "UTF-16", "UNICODE"};
        String charset = Charset.defaultCharset().displayName();
        CharsetDecoder decoder;
        BufferedReader br = null;
        String s = null;
        for (int i = 0; i < charsets.length; i++) {
            decoder = Charset.forName(charsets[i]).newDecoder();
            try {
                br = new BufferedReader(new InputStreamReader(new FileInputStream(filePath), decoder));
                do {
                    s = br.readLine();
                } while (s != null);
                charset = charsets[i];
                Log.d(TAG, "getTextFileCharset: is " + charsets[i] + ",break");
                break;
            } catch (FileNotFoundException e) {
                e.printStackTrace();
                break;
            } catch (MalformedInputException e) { //如果编码不能解码此文本就会抛出这个异常
                Log.d(TAG, "getTextFileCharset: not " + charsets[i] + ",continue");
                continue;
            } catch (IOException e) {
                e.printStackTrace();
                break;
            }
        }
        return charset;
        /*File file = new File(filePath);
        if (null == filePath || !file.exists() || file.isDirectory()) return charset;
        try {
            FileInputStream fis = new FileInputStream(file);
            BufferedInputStream bi = new BufferedInputStream(fis);
            byte[] header = new byte[3];
            bi.read(header);
            if (header[0] == (byte) 0xEF && header[1] == (byte) 0xBB
                    && header[2] == (byte) 0xBF) {// utf-8
                charset = "UTF-8";
            } else if (header[0] == (byte) 0xFF
                    && header[1] == (byte) 0xFE) {
                charset = "UNICODE";
            } else if (header[0] == (byte) 0xFE
                    && header[1] == (byte) 0xFF) {
                charset = "UTF-16BE";
            } else if (header[0] == (byte) 0xFF
                    && header[1] == (byte) 0xFF) {
                charset = "UTF-16LE";
            } else {
                charset = "GBK";
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        Log.d(TAG, "getTextFileCharset: charset = " + charset);
        return charset;*/
    }

这种方式无需第三方库，特此记录