SpannableString

public class SpannableString {
    public void setSpan(Object what, int start, int end, int flags) {
        super.setSpan(what, start, end, flags);
    }
}

SpannableString四个参数含义:

参数	含义
Object	泛型, 可以设置颜色, 间距, 点击事件等
int	目标文字的起始点
int	目标文字的终点
int	其他文字效果

flags对应四个值:

public interface Spanned {
    /**
     * Non-0-length spans of type SPAN_INCLUSIVE_EXCLUSIVE expand
     * to include text inserted at their starting point but not at their
     * ending point.  When 0-length, they behave like marks.
     */
    public static final int SPAN_INCLUSIVE_EXCLUSIVE = SPAN_MARK_MARK;

    /**
     * Spans of type SPAN_INCLUSIVE_INCLUSIVE expand
     * to include text inserted at either their starting or ending point.
     */
    public static final int SPAN_INCLUSIVE_INCLUSIVE = SPAN_MARK_POINT;

    /**
     * Spans of type SPAN_EXCLUSIVE_EXCLUSIVE do not expand
     * to include text inserted at either their starting or ending point.
     * They can never have a length of 0 and are automatically removed
     * from the buffer if all the text they cover is removed.
     */
    public static final int SPAN_EXCLUSIVE_EXCLUSIVE = SPAN_POINT_MARK;

    /**
     * Non-0-length spans of type SPAN_EXCLUSIVE_INCLUSIVE expand
     * to include text inserted at their ending point but not at their
     * starting point.  When 0-length, they behave like points.
     */
    public static final int SPAN_EXCLUSIVE_INCLUSIVE = SPAN_POINT_POINT;
}

当在被选中文字左右插入文字时, 插入字段是否也会应用该样式;

参数	含义
SPAN_INCLUSIVE_EXCLUSIVE	包前不包后
SPAN_INCLUSIVE_EXCLUSIVE	包前包后
SPAN_EXCLUSIVE_EXCLUSIVE	不包前不包后
SPAN_EXCLUSIVE_INCLUSIVE	不包前包后

http://blog.csdn.net/jdsjlzx/article/details/19122103
http://www.jb51.net/article/104028.htm
http://blog.csdn.net/qq_16430735/article/details/50427978#textappearancespan