Luke Dennis Luke Dennis - 1 month ago 20
Javascript Question

Famo.us: How to put form fields inside a scrolling view that works on iOS and Safari?

I’m trying to create a scrolling form for a mobile web app using a Famous ScrollView. However, iOS exhibits severe display bugs when scrolling while the keyboard is active. This occurs whether using an InputSurface or embedding an

<input>
directly in the Surface HTML.

What’s the best way to achieve a scrollable input form that supports Mobile Safari?

(JSFiddle code replicated below; to see the bug, tap on a text field and then attempt to scroll while keyboard is active.)

Famous.loaded(function () {
var Engine = Famous.Core.Engine;
var Surface = Famous.Core.Surface;
var Scrollview = Famous.Views.Scrollview;
var Transform = Famous.Core.Transform;

var mainContext = Engine.createContext();

var scrollview = new Scrollview();
var surfaces = [];

scrollview.sequenceFrom(surfaces);

var inputhtml = '<div><input type="text" value="test: edit me" /></div>';

for (var i = 0, temp; i < 40; i++) {
temp = new Surface({
content: inputhtml,
size: [undefined, 200],
properties: {
backgroundColor: "hsl(" + (i * 360 / 40) + ", 100%, 50%)",
lineHeight: "200px",
textAlign: "center"
},
index: i
});

temp.pipe(scrollview);
surfaces.push(temp);
}
mainContext.add(scrollview);
});

Answer

The issue is that famous scroll view is not truly scrollable , they animate the group so that it looks smooth , and to add the pull to refresh effect.

A solution for this : there is no really a direct and neat solution for this as the iOS keyboard animation will always focus into input and on the other hand famous uses a hidden indicator that works like a scroll bar , which conflicts with the iOS focus algorithm , so the only possible solution is that famous changes the way they animate scrollable view.

Workaround:

  • Fortunately there is workaround , if user will scroll away from input it means they may be not interested in inputting text anymore , so we can blur the target input once the view is scrolled.
  • after lot of searching I didnt really find a rigid event for famous to indicate scroll start event, however mutation observer worked well to achieve the required result.

Famo.us ScrollView MouseOver - jsFiddle demo

  <link rel="stylesheet" type="text/css" href="/css/result-light.css">


      <link rel="stylesheet" type="text/css" href="https://rawgit.com/jperl/famous-compiled/e9c12b1fa657820d3f9bad093ea72e8ee2dfec46/dist/lib/famous/core/famous.css">



      <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js"></script>
      <script type="text/javascript" src="http://rawgit.com/jperl/famous-compiled/e9c12b1fa657820d3f9bad093ea72e8ee2dfec46/dist/src/4f231991.polyfills.js"></script>

      <script type="text/javascript" src="https://rawgit.com/jperl/famous-compiled/97f85aaa64af255adfe0407c941e0e859b0759bc/dist/src/804b0adb.main.js"></script>


  <style>
    input { font-size: 40px; }
  </style>



<script type="text/javascript">
var observer;
window.onload=function(){
Famous.loaded(function () {
    var Engine = Famous.Core.Engine;
    var Surface = Famous.Core.Surface;
    var Modifier = Famous.Core.Modifier;
    var Scrollview = Famous.Views.Scrollview;
    var Transform = Famous.Core.Transform;

    var mainContext = Engine.createContext();

    var scrollview = new Scrollview();
    var surfaces = [];

    scrollview.sequenceFrom(surfaces);

    var inputhtml = '<div><input type="text" value="test: edit me" /></div>';

    for (var i = 0, temp; i < 40; i++) {
        temp = new Surface({
            content: inputhtml,
            size: [undefined, 200],
            properties: {
                backgroundColor: "hsl(" + (i * 360 / 40) + ", 100%, 50%)",
                lineHeight: "200px",
                textAlign: "center"
            },
            index: i
        });

        temp.pipe(scrollview);
        surfaces.push(temp);
    }
    mainContext.add(scrollview);

});
$("body").on("focus","input",function(){Observe($(this));});
$("body").on("blur","input",function(){endObserver();})
}


function Observe(event_input)
{
  var target = document.querySelector('.famous-group');

// create an observer instance
observer = new MutationObserver(function(mutations) {
  mutations.forEach(function(mutation) {
    event_input.blur();
    console.log(mutation.oldValue);
  });    
});

// configuration of the observer:
var config = { attributes: true, attributeOldValue: true, characterData: true };

// pass in the target node, as well as the observer options
observer.observe(target, config);
}
function endObserver()
{
  observer.disconnect();
}

</script>


</head>
<body>
</body>

</html>

The live example can be found on my page

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