Android Development: Count EditText Lines on textChanged?

问题

How can I count the number of lines in an EditText? Basically in my app I have line numbers and I wanted to make them update on textchange (I already have the textchangelistener set up). Is this possible? :(

Thanks, Alex!

回答1:

Lines can be differents:

• Visible lines: Wrapped text count as a new line...
• List item: Only lines with \r, \n, \r\n

First case (the easiest):

int nbLines = editText.getLineCount();

Second case:

        int nbLines = 0;
        StringReader     sr = new StringReader(editText.getText().toString());
        LineNumberReader lnr = new LineNumberReader(sr);
        try { 
            while (lnr.readLine() != null){}
            nbLines = lnr.getLineNumber();
            lnr.close();
        } catch (IOException e) {
            nbLines = editText.getLineCount();
        } finally {
            sr.close();
        }

回答2:

Depends on what you define as "line number". A line in your edittext in "GUI way", which includes the linebreaks your editview does? Or a line in a "coding way" of describing it (having \n at the end)? First one will be quite hard to get, if even impossible. Second one: just count the numbers of \n in the text, plus add another 1 if there is something after the last \n.

来源：https://stackoverflow.com/questions/4787736/android-development-count-edittext-lines-on-textchanged