android 更改TextView中任意位置字体大小和颜色的方法

TextView textView = (TextView) findViewById(R.id.text);
String textSource = "修改TextView中部分文字的<font color='#ff0000'><big>大</big><small>小</small></font>和<font color='#00ff00'>颜色</font>，展示多彩效果！";
textView.setText(Html.fromHtml(textSource));

textView = (TextView) findViewById(R.id.textview); 
SpannableStringBuilder builder = new SpannableStringBuilder(textView.getText().toString()); 
//ForegroundColorSpan 为文字前景色，BackgroundColorSpan为文字背景色 
ForegroundColorSpan redSpan = new ForegroundColorSpan(Color.RED); 
ForegroundColorSpan whiteSpan = new ForegroundColorSpan(Color.WHITE); 
ForegroundColorSpan blueSpan = new ForegroundColorSpan(Color.BLUE); 
ForegroundColorSpan greenSpan = new ForegroundColorSpan(Color.GREEN); 
ForegroundColorSpan yellowSpan = new ForegroundColorSpan(Color.YELLOW); 
builder.setSpan(redSpan, 0, 1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
builder.setSpan(whiteSpan, 1, 2, Spannable.SPAN_INCLUSIVE_INCLUSIVE); 
builder.setSpan(blueSpan, 2, 3, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
builder.setSpan(greenSpan, 3, 4, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
builder.setSpan(yellowSpan, 4,5, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE); 
textView.setText(builder);