TextWatcher tw = new TextWatcher() {

        @Override

        public void beforeTextChanged(CharSequence s, int start, int count,

                int after) {

            Log.e("beforeTextChanged", "-----------------------");

            Log.e("beforeTextChanged", "s:" + s + " start:" + start + " count:"

                    + count + " after:" + after);

            // s:之前的文字内容

            // start:添加文字的位置(从0开始)

            // count:不知道 一直是0

            // after:添加的文字总数

        }

        @Override

        public void onTextChanged(CharSequence s, int start, int before,

                int count) {

            Log.e("onTextChanged", "-----------------------");

            Log.e("onTextChanged", "s:" + s + " start:" + start + " before:"

                    + before + " count:" + count);

            // s:之后的文字内容

            // start:添加文字的位置(从0开始)

            // before:不知道 一直是0

            // before:添加的文字总数

        }

        @Override

        public void afterTextChanged(Editable s) {

            Log.e("afterTextChanged", "-----------------------");

            Log.e("afterTextChanged", "s:" + s);

            // s:之后的文字内容

        }

    };

    tv.addTextChangedListener(tw);