TextView中使用一个字符串替换字符串str中start到end的子字符串

sb.setSpan(new ReplacementSpan() {
				
				@Override
				public int getSize(Paint paint, CharSequence text, int start, int end,
						FontMetricsInt fm) {
					//最后一个参数为end-1，防止这个span最后与下一个字符之间有空格
					if (fm != null) {
						paint.getFontMetricsInt(fm);
					}
					return (int) paint.measureText(text, start, end);
				}
				
				@Override
				public void draw(Canvas canvas, CharSequence text, int start, int end,
						float x, int top, int y, int bottom, Paint paint) {
//			    	String newText = "****" + text.toString().substring(start + 4, end);
			    	paint.setUnderlineText(true);
			    	paint.setColor(linkColor);
			        canvas.drawText("****", 0, end - start, x, y, paint);
				}
			}, start, start + 4, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

代码如下：

sb.setSpan(new TypefaceSpan("monospace"), start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);