/
dragdrop.js
670 lines (586 loc) · 21 KB
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dragdrop.js
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/**
* The core drag and drop module for Moodle which extends the YUI drag and
* drop functionality with additional features.
*
* @module moodle-core-dragdrop
*/
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
*
* @class M.core.dragdrop
* @constructor
* @extends Base
*/
var DRAGDROP = function() {
DRAGDROP.superclass.constructor.apply(this, arguments);
};
Y.extend(DRAGDROP, Y.Base, {
/**
* Whether the item is being moved upwards compared with the last
* location.
*
* @property goingup
* @type Boolean
* @default null
*/
goingup: null,
/**
* Whether the item is being moved upwards compared with the start
* point.
*
* @property absgoingup
* @type Boolean
* @default null
*/
absgoingup: null,
/**
* The class for the object.
*
* @property samenodeclass
* @type String
* @default null
*/
samenodeclass: null,
/**
* The class on the parent of the item being moved.
*
* @property parentnodeclass
* @type String
* @default
*/
parentnodeclass: null,
/**
* The label to use with keyboard drag/drop to describe items of the same Node.
*
* @property samenodelabel
* @type Object
* @default null
*/
samenodelabel : null,
/**
* The label to use with keyboard drag/drop to describe items of the parent Node.
*
* @property samenodelabel
* @type Object
* @default null
*/
parentnodelabel : null,
/**
* The groups for this instance.
*
* @property groups
* @type Array
* @default []
*/
groups: [],
/**
* The previous drop location.
*
* @property lastdroptarget
* @type Node
* @default null
*/
lastdroptarget: null,
/**
* The initializer which sets up the move action.
*
* @method initializer
* @protected
*/
initializer: function() {
// 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);
// Add keybaord listeners for accessible drag/drop
Y.one(Y.config.doc.body).delegate('key', this.global_keydown,
'down:32, enter, esc', '.' + MOVEICON.cssclass, this);
// Make the accessible drag/drop respond to a single click.
Y.one(Y.config.doc.body).delegate('click', this.global_keydown,
'.' + MOVEICON.cssclass , this);
},
/**
* Build a new drag handle Node.
*
* @method get_drag_handle
* @param {String} title The title on the drag handle
* @param {String} classname The name of the class to add to the node
* wrapping the drag icon
* @param {String} [iconclass] The class to add to the icon
* @param {Boolean} [large=false] whether to use the larger version of
* the drag icon
* @return Node The built drag handle.
*/
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)
.setAttribute('role', 'button');
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);
drag.get('activeHandle').focus();
},
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) {
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,
info = e.info;
// Check that drag object belongs to correct group
if (!this.in_group(drag)) {
return;
}
// Note, we test both < and > situations here. We don't want to
// effect a change in direction if the user is only moving side
// to side with no Y position change.
// Detect changes in the position relative to the start point.
if (info.start[1] < info.xy[1]) {
// We are going up if our final position is higher than our start position.
this.absgoingup = true;
} else if (info.start[1] > info.xy[1]) {
// Otherwise we're going down.
this.absgoingup = false;
}
// Detect changes in the position relative to the last movement.
if (info.delta[1] < 0) {
// We are going up if our final position is higher than our start position.
this.goingup = true;
} else if (info.delta[1] > 0) {
// Otherwise we're going down.
this.goingup = false;
}
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'),
drop = e.drop.get('node');
// Save last drop target for the case of missed target processing.
this.lastdroptarget = e.drop;
// Are we dropping within the same parent node?
if (drop.hasClass(this.samenodeclass)) {
var where;
if (this.goingup) {
where = "before";
} else {
where = "after";
}
// Add the node contents so that it's moved, otherwise only the drag handle is moved.
drop.insert(drag, where);
} 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.
* @return {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 = '';
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;
// 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);
if (this.samenodelabel && node.hasClass(this.samenodeclass)) {
listitemtext = M.util.get_string(this.samenodelabel.identifier, this.samenodelabel.component, nodetitle);
} else if (this.parentnodelabel && node.hasClass(this.parentnodeclass)) {
listitemtext = M.util.get_string(this.parentnodelabel.identifier, this.parentnodelabel.component, nodetitle);
} else {
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'));
// 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,
center: true,
modal: true
});
M.core.dragdrop.dropui.after('visibleChange', function(e) {
// After the dialogue has been closed, we call the cancel function. This will
// ensure that tidying up happens (e.g. focusing on the start Node).
if (e.prevVal && !e.newVal) {
this.global_cancel_keyboard_drag();
}
}, this);
// 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()
*
* @method 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;
}
if (param === 'activeHandle') {
return this.node.one('.editing_move');
}
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;
// 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);
},
/**
* 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) {
// Focus on the node which was being dragged.
M.core.dragdrop.keydraghandle.focus();
M.core.dragdrop.keydragcontainer = null;
}
},
/**
* Process key events on the drag handles.
*
* @method global_keydown
* @param {EventFacade} e The keydown / click event on the drag handle.
*/
global_keydown: function(e) {
var draghandle = e.target.ancestor('.' + MOVEICON.cssclass, true),
dragcontainer,
draggroups;
if (draghandle === null) {
// The element clicked did not have a a draghandle in it's lineage.
return;
}
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 && e.type !== 'click') {
return;
}
// Check the drag groups to see if we are the handler for this node.
draggroups = draghandle.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.
/**
* Callback to use when dragging starts.
*
* @method drag_start
* @param {EventFacade} e
*/
drag_start: function() {},
/**
* Callback to use when dragging ends.
*
* @method drag_end
* @param {EventFacade} e
*/
drag_end: function() {},
/**
* Callback to use during dragging.
*
* @method drag_drag
* @param {EventFacade} e
*/
drag_drag: function() {},
/**
* Callback to use when dragging ends and is not over a drop target.
*
* @method drag_dropmiss
* @param {EventFacade} e
*/
drag_dropmiss: function() {},
/**
* Callback to use when a drop over event occurs.
*
* @method drop_over
* @param {EventFacade} e
*/
drop_over: function() {},
/**
* Callback to use on drop:hit.
*
* @method drop_hit
* @param {EventFacade} e
*/
drop_hit: function() {}
}, {
NAME: 'dragdrop',
ATTRS: {}
});
M.core = M.core || {};
M.core.dragdrop = DRAGDROP;