moodle/lib/yui/dragdrop/dragdrop.js
Damyon Wiese ea8c248c96 MDL-36002 keyboard drag drop: Hidden activities and labels
Get the correct title for hidden activities and labels.
2013-08-19 16:18:23 +08:00

482 lines
18 KiB
JavaScript

YUI.add('moodle-core-dragdrop', function(Y) {
var MOVEICON = {
pix: "i/move_2d",
largepix: "i/dragdrop",
component: 'moodle',
cssclass: 'moodle-core-dragdrop-draghandle'
};
/*
* General DRAGDROP class, this should not be used directly,
* it is supposed to be extended by your class
*/
var DRAGDROP = function() {
DRAGDROP.superclass.constructor.apply(this, arguments);
};
Y.extend(DRAGDROP, Y.Base, {
goingup : null,
lasty : null,
samenodeclass : null,
parentnodeclass : null,
groups : [],
lastdroptarget : null,
initializer : function(params) {
// Listen for all drag:start events
Y.DD.DDM.on('drag:start', this.global_drag_start, this);
// Listen for all drag:end events
Y.DD.DDM.on('drag:end', this.global_drag_end, this);
// Listen for all drag:drag events
Y.DD.DDM.on('drag:drag', this.global_drag_drag, this);
// Listen for all drop:over events
Y.DD.DDM.on('drop:over', this.global_drop_over, this);
// Listen for all drop:hit events
Y.DD.DDM.on('drop:hit', this.global_drop_hit, this);
// Listen for all drop:miss events
Y.DD.DDM.on('drag:dropmiss', this.global_drag_dropmiss, this);
Y.on('key', this.global_keydown, window, 'down:32,enter,esc', this);
},
get_drag_handle: function(title, classname, iconclass, large) {
var iconname = MOVEICON.pix;
if (large) {
iconname = MOVEICON.largepix;
}
var dragicon = Y.Node.create('<img />')
.setStyle('cursor', 'move')
.setAttrs({
'src' : M.util.image_url(iconname, MOVEICON.component),
'alt' : title
});
if (iconclass) {
dragicon.addClass(iconclass);
}
var dragelement = Y.Node.create('<span></span>')
.addClass(classname)
.setAttribute('title', title)
.setAttribute('tabIndex', 0)
.setAttribute('data-draggroups', this.groups);
dragelement.appendChild(dragicon);
dragelement.addClass(MOVEICON.cssclass);
return dragelement;
},
lock_drag_handle: function(drag, classname) {
drag.removeHandle('.'+classname);
},
unlock_drag_handle: function(drag, classname) {
drag.addHandle('.'+classname);
},
ajax_failure: function(response) {
var e = {
name : response.status+' '+response.statusText,
message : response.responseText
};
return new M.core.exception(e);
},
in_group: function(target) {
var ret = false;
Y.each(this.groups, function(v, k) {
if (target._groups[v]) {
ret = true;
}
}, this);
return ret;
},
/*
* Drag-dropping related functions
*/
global_drag_start : function(e) {
// Get our drag object
var drag = e.target;
// Check that drag object belongs to correct group
if (!this.in_group(drag)) {
return;
}
// Set some general styles here
drag.get('node').setStyle('opacity', '.25');
drag.get('dragNode').setStyles({
opacity: '.75',
borderColor: drag.get('node').getStyle('borderColor'),
backgroundColor: drag.get('node').getStyle('backgroundColor')
});
drag.get('dragNode').empty();
this.drag_start(e);
},
global_drag_end : function(e) {
var drag = e.target;
// Check that drag object belongs to correct group
if (!this.in_group(drag)) {
return;
}
//Put our general styles back
drag.get('node').setStyles({
visibility: '',
opacity: '1'
});
this.drag_end(e);
},
global_drag_drag : function(e) {
var drag = e.target;
// Check that drag object belongs to correct group
if (!this.in_group(drag)) {
return;
}
//Get the last y point
var y = drag.lastXY[1];
//is it greater than the lasty var?
if (y < this.lasty) {
//We are going up
this.goingup = true;
} else {
//We are going down.
this.goingup = false;
}
//Cache for next check
this.lasty = y;
this.drag_drag(e);
},
global_drop_over : function(e) {
// Check that drop object belong to correct group
if (!e.drop || !e.drop.inGroup(this.groups)) {
return;
}
//Get a reference to our drag and drop nodes
var drag = e.drag.get('node');
var drop = e.drop.get('node');
// Save last drop target for the case of missed target processing
this.lastdroptarget = e.drop;
//Are we dropping on the same node?
if (drop.hasClass(this.samenodeclass)) {
//Are we not going up?
if (!this.goingup) {
drop = drop.next('.'+this.samenodeclass);
}
//Add the node
e.drop.get('node').ancestor().insertBefore(drag, drop);
} else if ((drop.hasClass(this.parentnodeclass) || drop.test('[data-droptarget="1"]')) && !drop.contains(drag)) {
// We are dropping on parent node and it is empty
if (this.goingup) {
drop.append(drag);
} else {
drop.prepend(drag);
}
}
this.drop_over(e);
},
global_drag_dropmiss : function(e) {
// drag:dropmiss does not have e.drag and e.drop properties
// we substitute them for the ease of use. For e.drop we use,
// this.lastdroptarget (ghost node we use for indicating where to drop)
e.drag = e.target;
e.drop = this.lastdroptarget;
// Check that drag object belongs to correct group
if (!this.in_group(e.drag)) {
return;
}
// Check that drop object belong to correct group
if (!e.drop || !e.drop.inGroup(this.groups)) {
return;
}
this.drag_dropmiss(e);
},
global_drop_hit : function(e) {
// Check that drop object belong to correct group
if (!e.drop || !e.drop.inGroup(this.groups)) {
return;
}
this.drop_hit(e);
},
/**
* This is used to build the text for the heading of the keyboard
* drag drop menu and the text for the nodes in the list.
* @method find_element_text
* @param {Node} n The node to start searching for a valid text node.
* @returns {string} The text of the first text-like child node of n.
*/
find_element_text : function(n) {
// The valid node types to get text from.
var nodes = n.all('h2, h3, h4, h5, span, p, div.no-overflow, div.dimmed_text');
var text = '';
debugger;
nodes.each(function () {
if (text == '') {
if (Y.Lang.trim(this.get('text')) != '') {
text = this.get('text');
}
}
});
if (text != '') {
return text;
}
return M.util.get_string('emptydragdropregion', 'moodle');
},
/**
* This is used to initiate a keyboard version of a drag and drop.
* A dialog will open listing all the valid drop targets that can be selected
* using tab, tab, tab, enter.
* @method global_start_keyboard_drag
* @param {Event} e The keydown / click event on the grab handle.
* @param {Node} dragcontainer The resolved draggable node (an ancestor of the drag handle).
* @param {Node} draghandle The node that triggered this action.
*/
global_start_keyboard_drag : function(e, draghandle, dragcontainer) {
M.core.dragdrop.keydragcontainer = dragcontainer;
M.core.dragdrop.keydraghandle = draghandle;
// Indicate to a screenreader the node that is selected for drag and drop.
dragcontainer.setAttribute('aria-grabbed', 'true');
// Get the name of the thing to move.
var nodetitle = this.find_element_text(dragcontainer);
var dialogtitle = M.util.get_string('movecontent', 'moodle', nodetitle);
// Build the list of drop targets.
var droplist = Y.Node.create('<ul></ul>');
droplist.addClass('dragdrop-keyboard-drag');
var listitem;
var listitemtext;
// Search for possible drop targets.
var droptargets = Y.all('.' + this.samenodeclass + ', .' + this.parentnodeclass);
droptargets.each(function (node) {
var validdrop = false, labelroot = node;
if (node.drop && node.drop.inGroup(this.groups) && node.drop.get('node') != dragcontainer) {
// This is a drag and drop target with the same class as the grabbed node.
validdrop = true;
} else {
var elementgroups = node.getAttribute('data-draggroups').split(' ');
var i, j;
for (i = 0; i < elementgroups.length; i++) {
for (j = 0; j < this.groups.length; j++) {
if (elementgroups[i] == this.groups[j]) {
// This is a parent node of the grabbed node (used for dropping in empty sections).
validdrop = true;
// This node will have no text - so we get the first valid text from the parent.
labelroot = node.get('parentNode');
break;
}
}
if (validdrop) {
break;
}
}
}
if (validdrop) {
// It is a valid drop target - create a list item for it.
listitem = Y.Node.create('<li></li>');
listlink = Y.Node.create('<a></a>');
nodetitle = this.find_element_text(labelroot);
listitemtext = M.util.get_string('tocontent', 'moodle', nodetitle);
listlink.setContent(listitemtext);
// Add a data attribute so we can get the real drop target.
listlink.setAttribute('data-drop-target', node.get('id'));
// Notify the screen reader this is a valid drop target.
listlink.setAttribute('aria-dropeffect', 'move');
// Allow tabbing to the link.
listlink.setAttribute('tabindex', '0');
// Set the event listeners for enter, space or click.
listlink.on('click', this.global_keyboard_drop, this);
listlink.on('key', this.global_keyboard_drop, 'down:enter,32', this);
// Add to the list or drop targets.
listitem.append(listlink);
droplist.append(listitem);
}
}, this);
// Create the dialog for the interaction.
M.core.dragdrop.dropui = new M.core.dialogue({
headerContent : dialogtitle,
bodyContent : droplist,
draggable : true,
visible : true
});
// Focus the first drop target.
if (droplist.one('a')) {
droplist.one('a').focus();
}
},
/**
* This is used as a simulated drag/drop event in order to prevent any
* subtle bugs from creating a real instance of a drag drop event. This means
* there are no state changes in the Y.DD.DDM and any undefined functions
* will trigger an obvious and fatal error.
* The end result is that we call all our drag/drop handlers but do not bubble the
* event to anyone else.
*
* The functions/properties implemented in the wrapper are:
* e.target
* e.drag
* e.drop
* e.drag.get('node')
* e.drop.get('node')
* e.drag.addHandle()
* e.drag.removeHandle()
*
* @class simulated_drag_drop_event
* @param {Node} dragnode The drag container node
* @param {Node} dropnode The node to initiate the drop on
*/
simulated_drag_drop_event : function(dragnode, dropnode) {
// Subclass for wrapping both drag and drop.
var dragdropwrapper = function(node) {
this.node = node;
}
// Method e.drag.get() - get the node.
dragdropwrapper.prototype.get = function(param) {
if (param == 'node' || param == 'dragNode' || param == 'dropNode') {
return this.node;
}
return null;
};
// Method e.drag.inGroup() - we have already run the group checks before triggering the event.
dragdropwrapper.prototype.inGroup = function() {
return true;
};
// Method e.drag.addHandle() - we don't want to run this.
dragdropwrapper.prototype.addHandle = function() {};
// Method e.drag.removeHandle() - we don't want to run this.
dragdropwrapper.prototype.removeHandle = function() {};
// Create instances of the dragdropwrapper.
this.drop = new dragdropwrapper(dropnode);
this.drag = new dragdropwrapper(dragnode);
this.target = this.drop;
},
/**
* This is used to complete a keyboard version of a drag and drop.
* A drop event will be simulated based on the drag and drop nodes.
* @method global_keyboard_drop
* @param {Event} e The keydown / click event on the proxy drop node.
*/
global_keyboard_drop : function(e) {
// The drag node was saved.
var dragcontainer = M.core.dragdrop.keydragcontainer;
dragcontainer.setAttribute('aria-grabbed', 'false');
// The real drop node is stored in an attribute of the proxy.
var droptarget = Y.one('#' + e.target.getAttribute('data-drop-target'));
// Close the dialog.
M.core.dragdrop.dropui.hide();
// Cancel the event.
e.preventDefault();
// Convert to drag drop events.
var dragevent = new this.simulated_drag_drop_event(dragcontainer, dragcontainer);
var dropevent = new this.simulated_drag_drop_event(dragcontainer, droptarget);
// Simulate the full sequence.
this.drag_start(dragevent);
this.global_drop_over(dropevent);
this.global_drop_hit(dropevent);
M.core.dragdrop.keydraghandle.focus();
},
/**
* This is used to cancel a keyboard version of a drag and drop.
*
* @method global_cancel_keyboard_drag
*/
global_cancel_keyboard_drag : function() {
if (M.core.dragdrop.keydragcontainer) {
M.core.dragdrop.keydragcontainer.setAttribute('aria-grabbed', 'false');
M.core.dragdrop.keydraghandle.focus();
M.core.dragdrop.keydragcontainer = null;
}
},
/**
* Process key events on the drag handles.
* @method global_keydown
* @param {Event} e The keydown / click event on the drag handle.
*/
global_keydown : function(e) {
var draghandle = e.target,
dragcontainer,
draggroups;
if (e.keyCode == 27 ) {
// Escape to cancel from anywhere.
this.global_cancel_keyboard_drag();
e.preventDefault();
return;
}
// Only process events on a drag handle.
if (!draghandle.hasClass(MOVEICON.cssclass)) {
return;
}
// Do nothing if not space or enter.
if (e.keyCode != 13 && e.keyCode != 32) {
return;
}
// Check the drag groups to see if we are the handler for this node.
draggroups = e.target.getAttribute('data-draggroups').split(' ');
var i, j, validgroup = false;
for (i = 0; i < draggroups.length; i++) {
for (j = 0; j < this.groups.length; j++) {
if (draggroups[i] == this.groups[j]) {
validgroup = true;
break;
}
}
if (validgroup) {
break;
}
}
if (!validgroup) {
return;
}
// Valid event - start the keyboard drag.
dragcontainer = draghandle.ancestor('.yui3-dd-drop');
this.global_start_keyboard_drag(e, draghandle, dragcontainer);
e.preventDefault();
},
/*
* Abstract functions definitions
*/
drag_start : function(e) {},
drag_end : function(e) {},
drag_drag : function(e) {},
drag_dropmiss : function(e) {},
drop_over : function(e) {},
drop_hit : function(e) {}
}, {
NAME : 'dragdrop',
ATTRS : {}
});
M.core = M.core || {};
M.core.dragdrop = DRAGDROP;
}, '@VERSION@', {requires:['base', 'node', 'io', 'dom', 'dd', 'event-key', 'event-focus', 'moodle-core-notification']});