目的：
将TextView里文本中的某些关键字高亮，并且设置超链接，可以进行页面的跳转

实现方法：
使用SpannableString，采用正则表达来搜索文本中的关键字；
设置关键字的超链接通过重写ClickableSpan来实现

// 加载文章内容高亮多个关键字，只高亮一个关键字去掉循环
        String[] keywords = new String[] { "power", "internet" };
        SpannableString s = new SpannableString(getResources().getString(
                R.string.papercontent));
        for (int i = 0; i < keywords.length; i++) {
            Pattern p = Pattern.compile(keywords[i] + "\\W");
            Matcher m = p.matcher(s);
            while (m.find()) {
                int start = m.start();
                int end = m.end() - 1;
                Intent intent = new Intent(getApplicationContext(),
                        KeyWord.class);
                s.setSpan(new IntentSpan(intent), start, end,
                        Spannable.SPAN_EXCLUSIVE_INCLUSIVE);
            }
        }
        tvContent.setText(s);
        tvContent.setMovementMethod(LinkMovementMethod.getInstance());

/**
     * 重写ClickableSpan中的onClick，实现点击效果
     * @author zengjiyang
     */
    public class IntentSpan extends ClickableSpan implements ParcelableSpan {
        private Intent mIntent;

        public IntentSpan(Intent mIntent) {
            super();
            this.mIntent = mIntent;
        }

        @Override
        public int describeContents() {
            // TODO Auto-generated method stub
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            // TODO Auto-generated method stub
        }

        @Override
        public int getSpanTypeId() {
            // TODO Auto-generated method stub
            return 100;
        }

        @Override
        public void onClick(View widget) {
            // TODO Auto-generated method stub
            Context context = widget.getContext();
            context.startActivity(mIntent);
        }

        @Override
        public void updateDrawState(TextPaint ds) {
            // TODO Auto-generated method stub
            super.updateDrawState(ds);
            ds.setColor(Color.RED);
            ds.setUnderlineText(false);
            ds.bgColor = Color.TRANSPARENT;
        }

    }