# Titanium.UI.iOS.DynamicItemBehavior

Base dynamic configuration for an item.

Availability
3.2.0
9.2.0

# Overview

A dynamic item behavior configures the physics attributes for one or more items. These attributes, such as density and resistance, affects the behavior of the object when other behaviors, such as push forces or collisions, are applied to it. To define a dynamic behavior for an item:

  1. Use the Titanium.UI.iOS.createDynamicItemBehavior method to create and define the behavior.
  2. Use the Titanium.UI.iOS.DynamicItemBehavior.addItem method to add items to the behavior.
  3. Add the behavior to an Titanium.UI.iOS.Animator.

# Examples

# Simple Example

The following example create two blocks, which are pushed towards each other. Because the red block is more dense and has higher resistance than the blue block, the red block moves steadily to the left, while the blue block spins around unpredictably.

var win = Ti.UI.createWindow({backgroundColor: 'white', fullscreen: true});

// Create an Animator object using the window as the coordinate system
var animator = Ti.UI.iOS.createAnimator({referenceView: win});

// Create a red block
var redBlock = Ti.UI.createView({
    backgroundColor: 'red',
    width: 25,
    height: 25,
    top: 25,
    left: 25
});

// Change the physics attributes of the red block
var redDynamic = Ti.UI.iOS.createDynamicItemBehavior({
    density: 20.0,
    angularResistance: 1.0,
    friction: 1.0,
    resistance: 1.0,
    allowsRotation: false
});
redDynamic.addItem(redBlock);

// Apply a left push to the red block
var redPush = Ti.UI.iOS.createPushBehavior({
    pushDirection: {x: 2.0, y: 0.0}
});
redPush.addItem(redBlock);

// Create a blue block
var blueBlock = Ti.UI.createView({
    backgroundColor: 'blue',
    width: 50,
    height: 50,
    top: 25,
    right: 25
});

// Change the physics attributes of the blue block
var blueDynamic = Ti.UI.iOS.createDynamicItemBehavior({
    elasticity: 1.0,
});
blueDynamic.addItem(blueBlock);

// Apply a right push to the blue block
var bluePush = Ti.UI.iOS.createPushBehavior({
    pushDirection: {x: -2.0, y: 0.0}
});
bluePush.addItem(blueBlock);

// Create the collision behavior so the items can collide
var collision = Ti.UI.iOS.createCollisionBehavior();
collision.addItem(redBlock);
collision.addItem(blueBlock);

animator.addBehavior(redDynamic);
animator.addBehavior(redPush);
animator.addBehavior(blueDynamic);
animator.addBehavior(bluePush);
animator.addBehavior(collision);

// Start the animation when the window opens
win.addEventListener('open', function(e){
    animator.startAnimator();
});

win.add(redBlock);
win.add(blueBlock);
win.open();

# Properties

# allowsRotation

Availability
3.2.0
9.2.0
allowsRotation :Boolean

Specifies if this item can rotate.

Set to true to enable this behavior or false to disable.

Default: true


# angularResistance

Availability
3.2.0
9.2.0
angularResistance :Number

Specifies the angular resistance of this item.

The greater the value, the greater the angular damping and rotation slows to a stop faster.

Default: 0


# apiName READONLY

Availability
3.2.0
9.2.0
apiName :String

The name of the API that this proxy corresponds to.

The value of this property is the fully qualified name of the API. For example, Titanium.UI.Button returns Ti.UI.Button.


# bubbleParent

Availability
3.2.0
9.2.0
bubbleParent :Boolean

Indicates if the proxy will bubble an event to its parent.

Some proxies (most commonly views) have a relationship to other proxies, often established by the add() method. For example, for a button added to a window, a click event on the button would bubble up to the window. Other common parents are table sections to their rows, table views to their sections, and scrollable views to their views. Set this property to false to disable the bubbling to the proxy's parent.

Default: true


# density

Availability
3.2.0
9.2.0
density :Number

Specifies the relative mass density of this item.

An item's density along with its size determines its effective mass and affects its dynamic behavior.

Default: 1


# elasticity

Availability
3.2.0
9.2.0
elasticity :Number

Specifies the elasticity applied to collisions for this item.

A value of 0.0 indicates no bounce upon collision, while 1.0 indicates a completely elastic collision.

Default: 0


# friction

Availability
3.2.0
9.2.0
friction :Number

Specifies the linear resistance of the item when it slides against another item.

A value of 0.0 indicates no friction, while 1.0 indicates strong friction. Use higher numbers to apply even higher friction.

Default: 0


# items READONLY

Availability
3.2.0
9.2.0
items :Array<Titanium.UI.View>

Items added to this behavior.


# resistance

Availability
3.2.0
9.2.0
resistance :Number

Specifies the linear resistance of this item which reduces linear velocity over time.

A value of 0.0 indicates no velocity damping.

Default: 0

# Methods

# addAngularVelocityForItem

Availability
3.2.0
9.2.0
addAngularVelocityForItem(item, velocity) void

Adds a specified angular velocity for the item.

Parameters

Name Type Description
item Titanium.UI.View

Item to add the velocity for.

velocity Number

Velocity to add or subtract in radians per second. If the current velocity is positive, the item spins clockwise. A negative value means the item spins counter-clockwise.

Returns

Type
void

# addEventListener

Availability
3.2.0
9.2.0
addEventListener(name, callback) void

Adds the specified callback as an event listener for the named event.

Parameters

Name Type Description
name String

Name of the event.

callback Callback<Titanium.Event>

Callback function to invoke when the event is fired.

Returns

Type
void

# addItem

Availability
3.2.0
9.2.0
addItem(item) void

Adds an item to this behavior.

Parameters

Name Type Description
item Titanium.UI.View

View object to add to the behavior.

Returns

Type
void

# addLinearVelocityForItem

Availability
3.2.0
9.2.0
addLinearVelocityForItem(item, velocity) void

Adds a specified linear velocity for the item.

Parameters

Name Type Description
item Titanium.UI.View

Item to add the velocity for.

velocity Point

Velocity to add or substract in points per second in the x and y directions.

Returns

Type
void

# angularVelocityForItem

Availability
3.2.0
9.2.0
angularVelocityForItem(item) Number

Returns the angular velocity of the item.

Parameters

Name Type Description
item Titanium.UI.View

Item to retrieve the velocity of.

Returns

Type
Number

# applyProperties

Availability
3.2.0
9.2.0
applyProperties(props) void

Applies the properties to the proxy.

Properties are supplied as a dictionary. Each key-value pair in the object is applied to the proxy such that myproxy[key] = value.

Parameters

Name Type Description
props Dictionary

A dictionary of properties to apply.

Returns

Type
void

# fireEvent

Availability
3.2.0
9.2.0
fireEvent(name[, event]) void

Fires a synthesized event to any registered listeners.

Parameters

Name Type Description
name String

Name of the event.

event Dictionary

A dictionary of keys and values to add to the Titanium.Event object sent to the listeners.

Returns

Type
void

# linearVelocityForItem

Availability
3.2.0
9.2.0
linearVelocityForItem(item) Point

Returns the linear velocity of the item.

Parameters

Name Type Description
item Titanium.UI.View

Item to retrieve the velocity of.

Returns

Type
Point

# removeEventListener

Availability
3.2.0
9.2.0
removeEventListener(name, callback) void

Removes the specified callback as an event listener for the named event.

Multiple listeners can be registered for the same event, so the callback parameter is used to determine which listener to remove.

When adding a listener, you must save a reference to the callback function in order to remove the listener later:

var listener = function() { Ti.API.info("Event listener called."); }
window.addEventListener('click', listener);

To remove the listener, pass in a reference to the callback function:

window.removeEventListener('click', listener);

Parameters

Name Type Description
name String

Name of the event.

callback Callback<Titanium.Event>

Callback function to remove. Must be the same function passed to addEventListener.

Returns

Type
void

# removeItem

Availability
3.2.0
9.2.0
removeItem(item) void

Removes the specified item from this behavior.

Parameters

Name Type Description
item Titanium.UI.View

Item to remove.

Returns

Type
void