String.replaceAll（）在我的圈中不起作用

Question

So im trying to remove all the special characters in a phone number to leave just the digits, unfortunately it isn't working. I have looked up others solutions but they still arent working. Even after running it in a debugger, it seems the .replaceAll() method is simply not doing anything. here is my code below:

if (c !=null) {
            //populate database with first 100 texts of each contact
            dbs.open();
            //comparator address, count to 100
            String addressX = "";
            int count = 0;
            c.moveToFirst();
            for (int i = 0; i < c.getCount(); i++) {
                //get c address
                String addressY = c.getString(c.getColumnIndex("address"));
                addressY.replaceAll("[^0-9]+", "").trim();
                //one for the address, other to be able to sort threads by date  !Find better solution!
                if (!smsAddressList.contains(addressY)) {
                    //custom object so listview can be sorted by date desc
                    String date = c.getString(c.getColumnIndex("date"));
                    smsDateList.add(date);
                    smsAddressList.add(addressY);
                }
                //less than 100 texts, add to database, update comparator, add to count
                if (count < 100) {
                    c.moveToPosition(i);
                        addText(c);
                        addressX = addressY;
                        count++;
                    }
                //if more 100 texts, check to see if new address yet
                else if (count>100) {
                    //if still same address, just add count for the hell of it
                    if (addressX.equals(addressY)) {
                        count++;
                    }
                    //if new address, add text, reset count
                    else {
                        addText(c);
                        addressX = addressY;
                        count = 1;
                    }


                }


            }
        }

Answer 1

String.replaceAll() returns the modified string, it doesn't modify the string in-place. So you need something like:

addressY = addressY.replaceAll("[^0-9]+", "").trim();

I'm also pretty certain that trim is superfluous here since you're already stripping out white space with the replaceAll . Hence, you can get away with:

addressY = addressY.replaceAll("[^0-9]+", "");

Answer 2

String is immutable. replaceAll simply returns new String with the desired modification.

You need to do:

addressY = addressY.replaceAll("[^0-9]+", "").trim();

Answer 3

addressY = addressY.replaceAll("[^0-9]+", "").trim();

replaceAll方法创建一个新的String，因此您需要重新声明该变量。

Answer 4

确保将更改后的字符串分配给addressY

addressY = addressY.replaceAll("[^0-9]+", "").trim();