Text Highlighting and add notes function in epub reader ios

Question

I am developing epub reader for ios and android. I want to implement text highlights and add note function to my epub reader. And I want to know how to these functionality for fixed layout epub. I can get selected object by javascript:window.getSelection(). I want to save and retrieve these objects for future use. Here the code I used for highlighting and saving text:

var selection;
var storedSelections[];

function highlightText() {
if (window.getSelection) {
    selection = window.getSelection();
}
 if (selection.rangeCount > 0) {
    var range = selection.getRangeAt(0);
    var selectedText = range.toString();
    var span = document.createElement("span");
    span.id = "span_" + range.startOffset + "_" + range.endOffset ;
     alert(span.id);
    span.onclick = function() {
    myOnclikFunction(selectedText);};
span.setAttribute("class","uiWebviewHighlight");
    span.style.backgroundColor  = "skyblue";
    range.surroundContents(span);

    selection.removeAllRanges();
    selection.addRange(range);

    for (var i = 0; i < selection.rangeCount; i++) {
        storedSelections.push (selection.getRangeAt (i));
    }
    selection.removeAllRanges();
    localStorage.setItem('storedSelections',storedSelections);
}}

I used this code for retrieve highlighted text:

function ShowStoredSelections () {
storedSelections.length=0;
var retrieved= localStorage.getItem('storedSelections');
storedSelections.push (retrieved);
var selection = window.getSelection ();
for (var i = 0; i < storedSelections.length; i++) {
    selection.removeAllRanges ();
    selection.addRange (storedSelections[i]);
    if (selection.rangeCount > 0) {
        var range = selection.getRangeAt(0);
        var selectedText = range.toString();

        var span = document.createElement("span");
        span.id = "span_" + range.startOffset + "_" + range.endOffset ;
        span.onclick = function() {
            myOnclikFunction(selectedText);
        };
        span.setAttribute("class","uiWebviewHighlight");
        span.style.backgroundColor  = "red";
        range.surroundContents(span);
        selection.removeAllRanges();
        selection.addRange(range);
    }
}}

I can't add retrieved text to selection.addRange. What am I doing wrong in this?

Please give me some ideas or suggestions to overcome this problem.

Thanks in advance for any reply or answer.

Answer 1

I have implemented all these for native epub player of androd and iOS- its a product R&D for an organisation

Instead of using getSelection follow the below steps.Its tedious but functionality would be fully under your control

-> Give url to UIWebView (iOS) or WebView (android)

-> in call back of webview didload - wrap all text words into spans with unique ids

-> propagate touch events to webview- javascript will handle those touches using function onTouchMove(e)

-> get touched span using document.elementFromPoint

-> highlight those spans (words) -> You will get position of each span $('#wordID-'+sWordID).position(),you can pass those values from javascript to native code

-> Add sticky notes view to the super view of webview

Note: better inject jQuery in run time into webview for wrapping words into spans