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## Sencha Documentation

# Ext.dd.DragTracker

####

    MixinsExt.util.Observable

A DragTracker listens for drag events on an Element and fires events at the start and end of the drag, as well as during the drag. This is useful for components such as Ext.slider.Multi, where there is an element that can be dragged around to change the Slider's value. DragTracker provides a series of template methods that should be overridden to provide functionality in response to detected drag operations. These are onBeforeStart, onStart, onDrag and onEnd. See Ext.slider.Multi's initEvents function for an example implementation.

Defined By

### Config Options

#### CSS Class configs

Ext.dd.DragTracker
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overCls : String
A CSS class to add to the DragTracker's target element when the element (or, if the delegate option is used, when a d...

A CSS class to add to the DragTracker's target element when the element (or, if the delegate option is used, when a delegate element) is mouseovered.

If the delegate option is used, these events fire only when a delegate element is entered of left..

#### Other Configs

Ext.dd.DragTracker
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autoStart : Boolean/Number
Defaults to false. Specify true to defer trigger start by 1000 ms. Specify a Number for the number of milliseconds to...

Defaults to `false`. Specify `true` to defer trigger start by 1000 ms. Specify a Number for the number of milliseconds to defer trigger start.

Ext.dd.DragTracker
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constrainTo : Ext.util.Region/Element
A Region (Or an element from which a Region measurement will be read) which is used to constrain the result of the ge...

A Region (Or an element from which a Region measurement will be read) which is used to constrain the result of the getOffset call.

This may be set any time during the DragTracker's lifecycle to set a dynamic constraining region.

Ext.dd.DragTracker
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delegate : String
Optional. A DomQuery selector which identifies child elements within the DragTracker's encapsulating Element which ar...

Optional.

A DomQuery selector which identifies child elements within the DragTracker's encapsulating Element which are the tracked elements. This limits tracking to only begin when the matching elements are mousedowned.

This may also be a specific child element within the DragTracker's encapsulating element to use as the tracked element.

Ext.util.Observable
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listeners : Object
(optional) A config object containing one or more event handlers to be added to this object during initialization. T...

(optional)

A config object containing one or more event handlers to be added to this object during initialization. This should be a valid listeners config object as specified in the addListener example for attaching multiple handlers at once.

DOM events from ExtJs Components

While some ExtJs Component classes export selected DOM events (e.g. "click", "mouseover" etc), this

is usually only done when extra value can be added. For example the DataView's `click` event passing the node clicked on. To access DOM events directly from a child element of a Component, we need to specify the `element` option to identify the Component property to add a DOM listener to:

    new Ext.panel.Panel({
        width: 400,
        height: 200,
        dockedItems: [{
            xtype: 'toolbar'
        }],
        listeners: {
            click: {
                element: 'el', //bind to the underlying el property on the panel
                fn: function(){ console.log('click el'); }
            },
            dblclick: {
                element: 'body', //bind to the underlying body property on the panel
                fn: function(){ console.log('dblclick body'); }
            }
        }
    });

Ext.dd.DragTracker
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overCls : String
A CSS class to add to the DragTracker's target element when the element (or, if the delegate option is used, when a d...

A CSS class to add to the DragTracker's target element when the element (or, if the delegate option is used, when a delegate element) is mouseovered.

If the delegate option is used, these events fire only when a delegate element is entered of left..

Ext.dd.DragTracker
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preventDefault : Boolean

Specify `false` to enable default actions on onMouseDown events. Defaults to `true`.

Specify `false` to enable default actions on onMouseDown events. Defaults to `true`.

Ext.dd.DragTracker
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stopEvent : Boolean
Specify true to stop the mousedown event from bubbling to outer listeners from the target element (or its delegates)....

Specify `true` to stop the `mousedown` event from bubbling to outer listeners from the target element (or its delegates). Defaults to `false`.

Ext.dd.DragTracker
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tolerance : Number

Number of pixels the drag target must be moved before dragging is considered to have started. Defaults to `5`.

Number of pixels the drag target must be moved before dragging is considered to have started. Defaults to `5`.

Ext.dd.DragTracker
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trackOver : Boolean
Defaults to false. Set to true to fire mouseover and mouseout events when the mouse enters or leaves the target eleme...

Defaults to `false`. Set to true to fire mouseover and mouseout events when the mouse enters or leaves the target element.

This is implicitly set when an overCls is specified.

If the delegate option is used, these events fire only when a delegate element is entered of left..

Defined By

### Properties

Ext.dd.DragTracker
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active : Boolean

Read-only property indicated whether the user is currently dragging this tracker.

Read-only property indicated whether the user is currently dragging this tracker.

Ext.dd.DragTracker
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dragTarget : HtmlElement
Only valid during drag operations. Read-only. The element being dragged. If the delegate option is used, this wil...

Only valid during drag operations. Read-only.

The element being dragged.

If the delegate option is used, this will be the delegate element which was mousedowned.

Defined By

### Methods

Ext.util.Observable
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addEvents( Object/String o, String ) : void

Adds the specified events to the list of events which this Observable may fire.

Adds the specified events to the list of events which this Observable may fire.

### Parameters

- o : Object/String

  Either an object with event names as properties with a value of `true` or the first event name string if multiple event names are being passed as separate parameters.

- : String

  [additional] Optional additional event names if multiple event names are being passed as separate parameters. Usage:

      this.addEvents('storeloaded', 'storecleared');

### Returns

- void

Ext.util.Observable
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addListener( String eventName, Function handler, [Object scope], [Object options]) : void

Appends an event handler to this object.

Appends an event handler to this object.

### Parameters

- eventName : String

  The name of the event to listen for. May also be an object who's property names are event names. See

- handler : Function

  The method the event invokes.

- scope : Object

  (optional) The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.

- options : Object

  (optional) An object containing handler configuration. properties. This may contain any of the following properties:

  - scope : Object
    The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.
  - delay : Number
    The number of milliseconds to delay the invocation of the handler after the event fires.
  - single : Boolean
    True to add a handler to handle just the next firing of the event, and then remove itself.
  - buffer : Number
    Causes the handler to be scheduled to run in an Ext.util.DelayedTask delayed by the specified number of milliseconds. If the event fires again within that time, the original handler is not invoked, but the new handler is scheduled in its place.
  - target : Observable
    Only call the handler if the event was fired on the target Observable, not if the event was bubbled up from a child Observable.
  - element : String
    This option is only valid for listeners bound to Components. The name of a Component property which references an element to add a listener to.

    This option is useful during Component construction to add DOM event listeners to elements of Components which will exist only after the Component is rendered. For example, to add a click listener to a Panel's body:

        new Ext.panel.Panel({
            title: 'The title',
            listeners: {
                click: this.handlePanelClick,
                element: 'body'
            }
        });

    When added in this way, the options available are the options applicable to Ext.core.Element.addListener

  Combining Options
  Using the options argument, it is possible to combine different types of listeners:
  A delayed, one-time listener.

      myPanel.on('hide', this.handleClick, this, {
      single: true,
      delay: 100
      });

  Attaching multiple handlers in 1 call
  The method also allows for a single argument to be passed which is a config object containing properties which specify multiple events. For example:

      myGridPanel.on({
          cellClick: this.onCellClick,
          mouseover: this.onMouseOver,
          mouseout: this.onMouseOut,
          scope: this // Important. Ensure "this" is correct during handler execution
      });

  .

### Returns

- void

Ext.util.Observable
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addManagedListener( Observable/Element item, Object/String ename, Function fn, Object scope, Object opt) : void

Adds listeners to any Observable object (or Element) which are automatically removed when this Component is destroyed.

Adds listeners to any Observable object (or Element) which are automatically removed when this Component is destroyed.

### Parameters

- item : Observable/Element

  The item to which to add a listener/listeners.

- ename : Object/String

  The event name, or an object containing event name properties.

- fn : Function

  Optional. If the `ename` parameter was an event name, this is the handler function.

- scope : Object

  Optional. If the `ename` parameter was an event name, this is the scope (`this` reference) in which the handler function is executed.

- opt : Object

  Optional. If the `ename` parameter was an event name, this is the addListener options.

### Returns

- void

Ext.util.Observable
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capture( Observable o, Function fn, [Object scope]) : void
Starts capture on the specified Observable. All events will be passed to the supplied function with the event name + ...

Starts capture on the specified Observable. All events will be passed to the supplied function with the event name + standard signature of the event before the event is fired. If the supplied function returns false, the event will not fire.

### Parameters

- o : Observable

  The Observable to capture events from.

- fn : Function

  The function to call when an event is fired.

- scope : Object

  (optional) The scope (`this` reference) in which the function is executed. Defaults to the Observable firing the event.

### Returns

- void

Ext.util.Observable
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clearListeners : void

Removes all listeners for this object including the managed listeners

Removes all listeners for this object including the managed listeners

### Returns

- void

Ext.util.Observable
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clearManagedListeners : void

Removes all managed listeners for this object.

Removes all managed listeners for this object.

### Returns

- void

Ext.util.Observable
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enableBubble( String/Array events) : void
Enables events fired by this Observable to bubble up an owner hierarchy by calling this.getBubbleTarget() if present....

Enables events fired by this Observable to bubble up an owner hierarchy by calling `this.getBubbleTarget()` if present. There is no implementation in the Observable base class.

This is commonly used by Ext.Components to bubble events to owner Containers. See Ext.Component.getBubbleTarget. The default implementation in Ext.Component returns the Component's immediate owner. But if a known target is required, this can be overridden to access the required target more quickly.

Example:

    Ext.override(Ext.form.field.Base, {
    //  Add functionality to Field's initComponent to enable the change event to bubble
    initComponent : Ext.Function.createSequence(Ext.form.field.Base.prototype.initComponent, function() {
        this.enableBubble('change');
    }),

    //  We know that we want Field's events to bubble directly to the FormPanel.
    getBubbleTarget : function() {
        if (!this.formPanel) {
            this.formPanel = this.findParentByType('form');
        }
        return this.formPanel;
    }
    });

    var myForm = new Ext.formPanel({
    title: 'User Details',
    items: [{
        ...
    }],
    listeners: {
        change: function() {
            // Title goes red if form has been modified.
            myForm.header.setStyle('color', 'red');
        }
    }
    });

### Parameters

- events : String/Array

  The event name to bubble, or an Array of event names.

### Returns

- void

Ext.util.Observable
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fireEvent( String eventName, Object... args) : Boolean
Fires the specified event with the passed parameters (minus the event name). An event may be set to bubble up an Ob...

Fires the specified event with the passed parameters (minus the event name).

An event may be set to bubble up an Observable parent hierarchy (See Ext.Component.getBubbleTarget) by calling enableBubble.

### Parameters

- eventName : String

  The name of the event to fire.

- args : Object...

  Variable number of parameters are passed to handlers.

### Returns

- Boolean

  returns false if any of the handlers return false otherwise it returns true.

Ext.dd.DragTracker
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getDragTarget : Ext.core.Element
Returns the drag target. This is usually the DragTracker's encapsulating element. If the delegate option is being us...

Returns the drag target. This is usually the DragTracker's encapsulating element.

If the delegate option is being used, this may be a child element which matches the delegate selector.

### Returns

- Ext.core.Element

  The element currently being tracked.

Ext.dd.DragTracker
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getOffset( Object constrainMode) : Array
Returns the X, Y offset of the current mouse position from the mousedown point. This method may optionally constrai...

Returns the X, Y offset of the current mouse position from the mousedown point.

This method may optionally constrain the real offset values, and returns a point coerced in one of two modes:

- `point`
  The current mouse position is coerced into the constrainRegion, and the resulting position is returned.
- `dragTarget`
  The new Region of the dragTarget is calculated based upon the current mouse position, and then coerced into the constrainRegion. The returned mouse position is then adjusted by the same delta as was used to coerce the region.

### Parameters

- constrainMode : Object

  {String} Optional. If omitted the true mouse position is returned. May be passed as `'point'` or `'dragTarget'. See above.`.

### Returns

- Array

  The `X, Y` offset from the mousedown point, optionally constrained.

Ext.util.Observable
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hasListener( String eventName) : Boolean

Checks to see if this object has any listeners for a specified event

Checks to see if this object has any listeners for a specified event

### Parameters

- eventName : String

  The name of the event to check for

### Returns

- Boolean

  True if the event is being listened for, else false

Ext.dd.DragTracker
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initEl( Ext.core.Element/HTMLElement el) : void

Initializes the DragTracker on a given element.

Initializes the DragTracker on a given element.

### Parameters

- el : Ext.core.Element/HTMLElement

  The element

### Returns

- void

Ext.util.Observable
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observe( Function c, Object listeners) : void
Sets observability on the passed class constructor. This makes any event fired on any instance of the passed class a...

Sets observability on the passed class constructor.

This makes any event fired on any instance of the passed class also fire a single event through the class allowing for central handling of events on many instances at once.

Usage:

    Ext.util.Observable.observe(Ext.data.Connection);
    Ext.data.Connection.on('beforerequest', function(con, options) {
        console.log('Ajax request made to ' + options.url);
    });

### Parameters

- c : Function

  The class constructor to make observable.

- listeners : Object

  An object containing a series of listeners to add. See addListener.

### Returns

- void

Ext.util.Observable
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on( String eventName, Function handler, [Object scope], [Object options]) : void

Appends an event handler to this object (shorthand for addListener.)

Appends an event handler to this object (shorthand for addListener.)

### Parameters

- eventName : String

  The type of event to listen for

- handler : Function

  The method the event invokes

- scope : Object

  (optional) The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.

- options : Object

  (optional) An object containing handler configuration.

### Returns

- void

Ext.dd.DragTracker
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onBeforeStart( Ext.EventObject e) : void
Template method which should be overridden by each DragTracker instance. Called when the user first clicks and holds ...

Template method which should be overridden by each DragTracker instance. Called when the user first clicks and holds the mouse button down. Return false to disallow the drag

### Parameters

- e : Ext.EventObject

  The event object

### Returns

- void

Ext.dd.DragTracker
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onDrag( Ext.EventObject e) : void

Template method which should be overridden by each DragTracker instance. Called whenever a drag has been detected.

Template method which should be overridden by each DragTracker instance. Called whenever a drag has been detected.

### Parameters

- e : Ext.EventObject

  The event object

### Returns

- void

Ext.dd.DragTracker
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onEnd( Ext.EventObject e) : void
Template method which should be overridden by each DragTracker instance. Called when a drag operation has been comple...

Template method which should be overridden by each DragTracker instance. Called when a drag operation has been completed (e.g. the user clicked and held the mouse down, dragged the element and then released the mouse button)

### Parameters

- e : Ext.EventObject

  The event object

### Returns

- void

Ext.dd.DragTracker
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onStart( Ext.EventObject e) : void
Template method which should be overridden by each DragTracker instance. Called when a drag operation starts (e.g. th...

Template method which should be overridden by each DragTracker instance. Called when a drag operation starts (e.g. the user has moved the tracked element beyond the specified tolerance)

### Parameters

- e : Ext.EventObject

  The event object

### Returns

- void

Ext.util.Observable
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relayEvents( Object origin, Array events, Object prefix) : void

Relays selected events from the specified Observable as if the events were fired by `this`.

Relays selected events from the specified Observable as if the events were fired by `this`.

### Parameters

- origin : Object

  The Observable whose events this object is to relay.

- events : Array

  Array of event names to relay.

- prefix : Object

### Returns

- void

Ext.util.Observable
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releaseCapture( Observable o) : void

Removes all added captures from the Observable.

Removes all added captures from the Observable.

### Parameters

- o : Observable

  The Observable to release

### Returns

- void

Ext.util.Observable
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removeListener( String eventName, Function handler, [Object scope]) : void

Removes an event handler.

Removes an event handler.

### Parameters

- eventName : String

  The type of event the handler was associated with.

- handler : Function

  The handler to remove. This must be a reference to the function passed into the addListener call.

- scope : Object

  (optional) The scope originally specified for the handler.

### Returns

- void

Ext.util.Observable
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removeManagedListener( Observable|Element item, Object|String ename, Function fn, Object scope) : void

Removes listeners that were added by the mon method.

Removes listeners that were added by the mon method.

### Parameters

- item : Observable|Element

  The item from which to remove a listener/listeners.

- ename : Object|String

  The event name, or an object containing event name properties.

- fn : Function

  Optional. If the `ename` parameter was an event name, this is the handler function.

- scope : Object

  Optional. If the `ename` parameter was an event name, this is the scope (`this` reference) in which the handler function is executed.

### Returns

- void

Ext.util.Observable
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resumeEvents : void
Resume firing events. (see suspendEvents) If events were suspended using the queueSuspended parameter, then all event...

Resume firing events. (see suspendEvents) If events were suspended using the `queueSuspended` parameter, then all events fired during event suspension will be sent to any listeners now.

### Returns

- void

Ext.util.Observable
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suspendEvents( Boolean queueSuspended) : void

Suspend the firing of all events. (see resumeEvents)

Suspend the firing of all events. (see resumeEvents)

### Parameters

- queueSuspended : Boolean

  Pass as true to queue up suspended events to be fired after the resumeEvents call instead of discarding all suspended events;

### Returns

- void

Ext.util.Observable
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un( String eventName, Function handler, [Object scope]) : void

Removes an event handler (shorthand for removeListener.)

Removes an event handler (shorthand for removeListener.)

### Parameters

- eventName : String

  The type of event the handler was associated with.

- handler : Function

  The handler to remove. This must be a reference to the function passed into the addListener call.

- scope : Object

  (optional) The scope originally specified for the handler.

### Returns

- void

Defined By

### Events

Ext.dd.DragTracker
view source
drag( Object this, Object e)

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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dragend( Object this, Object e)

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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dragstart( Object this, Object e)

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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mousedown( Object this, Object e)
Fires when the mouse button is pressed down, but before a drag operation begins. The drag operation begins after eith...

Fires when the mouse button is pressed down, but before a drag operation begins. The drag operation begins after either the mouse has been moved by tolerance pixels, or after the autoStart timer fires.

Return false to veto the drag operation.

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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mousemove( Object this, Object e)

Fired when the mouse is moved. Returning false cancels the drag operation.

Fired when the mouse is moved. Returning false cancels the drag operation.

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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mouseout( Object this, Object e)
Only available when trackOver is true Fires when the mouse exits the DragTracker's target element (or if delegate i...

Only available when trackOver is `true`

Fires when the mouse exits the DragTracker's target element (or if delegate is used, when the mouse exits a delegate element).

### Parameters

- this : Object
- e : Object

  event object

Ext.dd.DragTracker
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mouseover( Object this, Object e, HtmlElement target)
Only available when trackOver is true Fires when the mouse enters the DragTracker's target element (or if delegate ...

Only available when trackOver is `true`

Fires when the mouse enters the DragTracker's target element (or if delegate is used, when the mouse enters a delegate element).

### Parameters

- this : Object
- e : Object

  event object

- target : HtmlElement

  The element mouseovered.

Ext.dd.DragTracker
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mouseup( Object this, Object e)

### Parameters

- this : Object
- e : Object

  event object