# Titanium.UI.ImageView
A view to display a single image or series of animated images.
# Overview
Use the Titanium.UI.createImageView method or <ImageView>
Alloy element to create an ImageView
.
Specifying either a width
or height
property for this view will scale its image(s) with
the aspect ratio maintained, up to a maximum size that does not exceed its parent view.
# Remote Images
You can display both local and remote images in an ImageView. When loading remote images, you should set the defaultImage property to a local image, which will be displayed while the remote image is being downloaded. Remote images are cached automatically on the iOS-, Android- and Windows platform.
Android Note: Android 6 and later uses runtime permissions to secure the user's privacy. Therefore, you should call Titanium.Filesystem.requestStoragePermissions before attempting to load remote images.
Read more about remote images and general best practices in the Image Best Practices Guide (opens new window).
# Android 9-Patch Scaled Images
A nine-patch (9-patch) image is simply a standard png
image with a transparent border of a
single pixel, containing "guides" defined by solid black (#000
) color fills. Guides added to the
top and left edges determine that the image may be stretched in horizontal and vertical planes
respectively. Optionally, the content area may be defined by guides added to the bottom and
right edges.
Although any image editor may be used to create the guides, certain settings can cause the edges
of the graphic to "bleed" into the transparent border, consequently making it non-transparent.
Thus, the draw9patch
utility provided in the Android SDK tools directory is recommended for
this purpose.
For further information about nine-patch images and the Android utility, see the Nine-patch (opens new window) and Draw 9-patch (opens new window) sections of the Android Developer website.
The nine-patch technique may be used with any of Titanium's static image properties. See the "Button with Nine-patch Background Image" example for a demonstration.
# Examples
# Basic Image View
In this example, we create a simple image view:
Ti.UI.backgroundColor = 'white';
var win = Ti.UI.createWindow();
var image = Ti.UI.createImageView({
image:'/images/myimage.png'
});
win.add(image);
win.open();
# Button with Nine-patch Background Image
Create a button with a nine-patch image background, that swaps with another image when selected, and generates a message in the console when clicked.
Note that images are referenced in the code without the .9
part of the filename, and that
the project should be cleaned to ensure that the files are correctly copied to the project.
var win = Ti.UI.createWindow({
backgroundColor: 'white',
exitOnClose: true,
fullscreen: false,
title: 'Click button to test'
});
var button = Ti.UI.createButton({
backgroundImage: '/images/custom-slider-right.png',
backgroundSelectedImage:'/images/custom-slider-left.png',
title: 'Click me!',
top: 10,
width: 300,
height: 200
});
button.addEventListener('click',function(e){
Ti.API.info("You clicked the button");
});
win.add(button);
win.open();
# Alloy XML Markup
Previous basic image view example as an Alloy view.
<Alloy>
<Window id="win" backgroundColor="white">
<ImageView id="image" image="/images/myimage.png" />
</Window>
</Alloy>
# Properties
# accessibilityDisableLongPress CREATION ONLY
Boolean value to remove the long press notification for the device's accessibility service.
Will disable the "double tap and hold for long press" message when selecting an item.
Default: true
Whether the view should be "hidden" from (i.e., ignored by) the accessibility service.
On iOS this is a direct analog of the accessibilityElementsHidden
property defined in the
UIAccessibility
Protocol.
On Android, setting accessibilityHidden
calls the native
View.setImportantForAccessibility
method. The native method is only available in Android 4.1 (API level 16/Jelly Bean) and
later; if this property is specified on earlier versions of Android, it is ignored.
Default: false
# accessibilityHint
Briefly describes what performing an action (such as a click) on the view will do.
On iOS this is a direct analog of the accessibilityHint
property defined in the
UIAccessibility Protocol.
On Android, it is concatenated together with
accessibilityLabel and accessibilityValue in the order: accessibilityLabel
,
accessibilityValue
, accessibilityHint
. The concatenated value is then passed as the
argument to the native View.setContentDescription method.
Default: null
# accessibilityLabel
A succint label identifying the view for the device's accessibility service.
On iOS this is a direct analog of the accessibilityLabel
property defined in the
UIAccessibility Protocol.
On Android, it is concatenated together with
accessibilityValue and accessibilityHint in the order: accessibilityLabel
,
accessibilityValue
, accessibilityHint
. The concatenated value is then passed as the
argument to the native View.setContentDescription method.
Defaults to Title or label of the control.
# accessibilityValue
A string describing the value (if any) of the view for the device's accessibility service.
On iOS this is a direct analog of the accessibilityValue
property defined in the
UIAccessibility Protocol.
On Android, it is concatenated together with
accessibilityLabel and accessibilityHint in the order: accessibilityLabel
,
accessibilityValue
, accessibilityHint
. The concatenated value is then passed as the
argument to the native View.setContentDescription method.
Defaults to State or value of the control.
# anchorPoint
Coordinate of the view about which to pivot an animation.
Used on iOS only. For Android, use anchorPoint.
Anchor point is specified as a fraction of the view's size. For example, {0, 0}
is at
the view's top-left corner, {0.5, 0.5}
at its center and {1, 1}
at its bottom-right
corner.
See the "Using an anchorPoint" example in Titanium.UI.Animation for a demonstration. The default is center of this view.
# animating READONLY
Indicates whether animation is running.
Default: false on creation, true on load (Android), false (iPhone, iPad)
# apiName READONLY
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
.
# autorotate CREATION ONLY
Indicates whether the image should be rotated based on EXIF orientation data.
Before Titanium 10.1.0, this defaulted to false
on Android.
Default: true
# backgroundColor
Background color of the view, as a color name or hex triplet.
For information about color values, see the "Colors" section of Titanium.UI. Defaults to Transparent
.
# backgroundDisabledColor
Disabled background color of the view, as a color name or hex triplet.
For information about color values, see the "Colors" section of Titanium.UI. Defaults to the normal background color of this view.
# backgroundDisabledImage
Disabled background image for the view, specified as a local file path or URL.
If backgroundDisabledImage
is undefined, and the normal background imagebackgroundImage
is set, the normal image is used when this view is disabled.
# backgroundFocusedColor
Focused background color of the view, as a color name or hex triplet.
For information about color values, see the "Colors" section of Titanium.UI.
For normal views, the focused color is only used if focusable
is true
.
Defaults to the normal background color of this view.
# backgroundFocusedImage
Focused background image for the view, specified as a local file path or URL.
For normal views, the focused background is only used if focusable
is true
.
If backgroundFocusedImage
is undefined, and the normal background image backgroundImage
is set, the normal image is used when this view is focused.
# backgroundGradient
A background gradient for the view.
A gradient can be defined as either linear or radial. A linear gradient varies continuously
along a line between the startPoint
and endPoint
.
A radial gradient is interpolated between two circles, defined by startPoint
and
startRadius
and endPoint
and endRadius
respectively.
The start points, end points and radius values can be defined in device units, in the view's coordinates, or as percentages of the view's size. Thus, if a view is 60 x 60, the center point of the view can be specified as:
{ x: 30, y: 30 }
Or:
{ x: '50%', y: '50%' }
When specifying multiple colors, you can specify an offset value for each color, defining how far into the gradient it takes effect. For example, the following color array specifies a gradient that goes from red to blue back to red:
colors: [ { color: 'red', offset: 0.0}, { color: 'blue', offset: 0.25 }, { color: 'red', offset: 1.0 } ]
Android's linear gradients ignores backfillStart
and backfillEnd
, treating them as if
they are true. Android's radial gradients ignore the endPoint
property.
Defaults to no gradient.
# backgroundImage
Background image for the view, specified as a local file path or URL.
Default behavior when backgroundImage
is unspecified depends on the type of view and the platform.
For generic views, no image is used. For most controls (buttons, textfields, and so on), platform-specific default images are used.
# backgroundLeftCap
Size of the left end cap.
See the section on backgroundLeftCap and backgroundTopCap behavior on iOS in Titanium.UI.View.
Default: 0
# backgroundRepeat
Determines whether to tile a background across a view.
Setting this to true
makes the set backgroundImage
repeat across the view as a series
of tiles. The tiling begins in the upper-left corner, where the upper-left corner of the
background image is rendered. The image is then tiled to fill the available space of the
view.
Note that setting this to true
may incur performance penalties for large views or
background images, as the tiling must be redone whenever a view is resized.
On iOS, the following views do not currently support tiled backgrounds:
Default: false
# backgroundSelectedColor
Selected background color of the view, as a color name or hex triplet.
For information about color values, see the "Colors" section of Titanium.UI.
focusable
must be true for normal views.
Defaults to background color of this view.
# backgroundSelectedImage
Selected background image url for the view, specified as a local file path or URL.
For normal views, the selected background is only used if focusable
is true
.
If backgroundSelectedImage
is undefined, and the normal background image backgroundImage
is set
the normal image is used when this view is selected.
# backgroundTopCap
Size of the top end cap.
See the section on backgroundLeftCap and backgroundTopCap behavior on iOS in Titanium.UI.View.
Default: 0
# borderColor
Border color of the view, as a color name or hex triplet.
For information about color values, see the "Colors" section of Titanium.UI.
Defaults to the normal background color of this view (Android), black (iOS).
# borderRadius
Radius for the rounded corners of the view's border.
Each corner is rounded using an arc of a circle.
Values for each corner can be specified. For example, '20px 20px' will set both left and right corners to 20px
.
Specifying '20px 20px 20px 20px' will set top-left, top-right, bottom-right and bottom-left corners in that order.
If you have issues with dark artifacts on Android you can try to disable Hardware acceleration by setting a
backgroundColor
with a small amount of transparency: backgroundColor:"rgba(255,255,255,254)"
.
Default: 0
# borderWidth
Border width of the view.
If borderColor is set without borderWidth, this value will be changed to 1 of the unit declared as 'ti.ui.defaultunit' in tiapp.xml descriptor.
Default: 0
# bottom
View's bottom position, in platform-specific units.
This position is relative to the view's parent. Exact interpretation depends on the parent view's layout property. Can be either a float value or a dimension string (for example, '50%' or '10px').
This is an input property for specifying where the view should be positioned, and does not represent the view's calculated position.
Defaults to undefined
.
# bubbleParent
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
# center
View's center position, in the parent view's coordinates.
This is an input property for specifying where the view should be positioned, and does not represent the view's calculated position.
Defaults to undefined
.
# clipMode
View's clipping behavior.
Setting this to CLIP_MODE_ENABLED enforces all child views to be clipped to this views bounds. Setting this to CLIP_MODE_DISABLED allows child views to be drawn outside the bounds of this view. When set to CLIP_MODE_DEFAULT or when this property is not set, clipping behavior is inferred. See section on iOS Clipping Behavior in Titanium.UI.View.
Defaults to undefined
. Behaves as if set to CLIP_MODE_DEFAULT.
# decodeRetries
Number of times to retry decoding the bitmap at a URL.
Defaults to 2 on Titanium 10.1.0 and higher. Defaults to 5 on older SDK versions.
Default: 2
# defaultImage
Local path to the default image to display while loading a remote image.
# duration
Amount of time in milliseconds to animate one cycle.
Starting with release 2.1.1, the minimum duration is 30 ms and the default duration is 200 ms.
On Android, prior to release 2.1.1, if any images are assigned to the images
property when the animation is
started, duration will be set to the number of images multiplied by 33 ms. If no images
are assigned, duration will be set to 100 ms.
On iOS, prior to release 2.1.1, the default is 30 ms.
On Android, if the value of duration is changed, stop and start need to be called for the new value to take effect.
Default: 200 ms in Release 2.1.1 and later. Platform-specific default in earlier releases.
# elevation
Base elevation of the view relative to its parent in pixels.
The elevation of a view determines the appearance of its shadow. Higher elevations produce larger and softer shadows.
Note: The elevation
property only works on Titanium.UI.View
objects.
Many Android components have a default elevation that cannot be modified.
For more information, see
Google design guidelines: Elevation and shadows.
# enableZoomControls
Show zoom controls when the user touches the image view.
Default: false
# filterTouchesWhenObscured
Discards touch related events if another app's system overlay covers the view.
This is a security feature to protect an app from "tapjacking", where a malicious app can use a system overlay to intercept touch events in your app or to trick the end-user to tap on UI in your app intended for the overlay.
Setting this property to true
causes touch related events (including "click") to not be fired
if a system overlay overlaps the view.
Default: false
# focusable
Whether view should be focusable while navigating with the trackball.
Default: false
# height
View height, in platform-specific units.
Defaults to: If undefined, defaults to either FILL or SIZE depending on the view. See "View Types and Default Layout Behavior" in Transitioning to the New UI Layout System.
Can be either a float value or a dimension string (for example, '50%' or '40dp'). Can also be one of the following special values:
- SIZE. The view should size itself to fit its contents.
- FILL. The view should size itself to fill its parent.
- 'auto'. Represents the default sizing behavior for a given type of
view. The use of 'auto' is deprecated, and should be replaced with the
SIZE
orFILL
constants if it is necessary to set the view's behavior explicitly.
This is an input property for specifying the view's height dimension. To determine the view's size once rendered, use the rect or size properties.
Sets the behavior when hiding an object to release or keep the free space
If setting hiddenBehavior
to HIDDEN_BEHAVIOR_GONE it will automatically release the space the view occupied.
For example: in a vertical layout the views below the object will move up when you hide
an object with hiddenBehavior:Titanium.UI.HIDDEN_BEHAVIOR_GONE
.
- HIDDEN_BEHAVIOR_INVISIBLE. Keeps the space and just hides the object (default).
- HIDDEN_BEHAVIOR_GONE. Releases the space and hides the object.
Defaults to Titanium.UI.HIDDEN_BEHAVIOR_INVISIBLE.
# hires
Set to true
to prevent scaling of 2x/3x-resolution remote images for retina
displays.
Causes images to display at 50%, where one pixel of the graphic maps to one physical pixel on-screen. This functionality is automatically determined for local images via their filenames, and thus this property is only applicable to remote images.
Default: false
# horizontalMotionEffect
Adds a horizontal parallax effect to the view
Note that the parallax effect only happens by tilting the device so results can not be seen on Simulator. To clear all motion effects, use the <Titanium.UI.clearMotionEffects> method.
# horizontalWrap
Determines whether the layout has wrapping behavior.
For more information, see the discussion of horizontal layout mode in the description of the layout property.
Default: true
# id
View's identifier.
The id
property of the Ti.UI.View represents the view's identifier. The identifier string does
not have to be unique. You can use this property with getViewById method.
# image
Image to display.
Image to display, defined using a local filesystem path, a File
object, a remote URL,
or a Blob
object containing image data.
For Android, if there is a redirect and change in protocol, it will not follow. For example, from http to https and vice versa. See Java Bug Database for more information.
# images
Array of images to animate, defined using local filesystem paths, File
objects,
remote URLs (Android only), or Blob
objects containing image data.
When using this property, an initial start()
needs to be called upon the ImageView before any image will show in this imageview.
Related properties/methods to look at: start
, stop
, pause
, reverse
, resume
and repeatCount
# imageTouchFeedback
Enables a ripple effect when the foreground image is touched.
Note that the touchFeedback property applies a ripple effect to the
view's background. If the image is opaque and completely covers the view (such as a photo),
then the background's ripple won't be visible. In this case, you should use this imageTouchFeedback
property to apply a ripple effect to the foreground image assigned via the image
property.
Default: false
# imageTouchFeedbackColor
Optional touch feedback ripple color. This has no effect unless imageTouchFeedback
is true.
Defaults to provided theme color.
# keepScreenOn
Determines whether to keep the device screen on.
When true
the screen will not power down. Note: enabling this feature will use more
power, thereby adversely affecting run time when on battery.
For iOS look at idleTimerDisabled.
Default: false
# layout
Specifies how the view positions its children. One of: 'composite', 'vertical', or 'horizontal'.
There are three layout options:
-
composite
(orabsolute
). Default layout. A child view is positioned based on its positioning properties or "pins" (top
,bottom
,left
,right
andcenter
). If no positioning properties are specified, the child is centered.The child is always sized based on its
width
andheight
properties, if these are specified. If the child's height or width is not specified explicitly, it may be calculated implicitly from the positioning properties. For example, if bothleft
andcenter.x
are specified, they can be used to calculate the width of the child control.Because the size and position properties can conflict, there is a specific precedence order for the layout properties. For vertical positioning, the precedence order is:
height
,top
,center.y
,bottom
.The following table summarizes the various combinations of properties that can be used for vertical positioning, in order from highest precedence to lowest. (For example, if
height
,center.y
andbottom
are all specified, theheight
andcenter.y
values take precedence.)Scenario Behavior height
&top
specifiedChild positioned top
unit from parent's top, using specifiedheight
; anycenter.y
andbottom
values are ignored.height
¢er.y
specifiedChild positioned with center at center.y
, using specifiedheight
; anybottom
value is ignored.height
&bottom
specifiedChild positioned bottom
units from parent's bottom, using specifiedheight
.top
¢er.y
specifiedChild positioned with top edge top
units from parent's top and center atcenter.y
. Height is determined implicitly; anybottom
value is ignored.top
&bottom
specifiedChild positioned with top edge top
units from parent's top and bottom edgebottom
units from parent's bottom. Height is determined implicitly.Only top
specifiedChild positioned top
units from parent's top, and uses the default height calculation for the view type.center.y
andbottom
specifiedChild positioned with center at center.y
and bottom edgebottom
units from parent's bottom. Height is determined implicitly.Only center.y
specifiedChild positioned with center at center.y
, and uses the default height calculation for the view type.Only bottom
specifiedChild positioned with bottom edge bottom
units from parent's bottom, and uses the default height calculation for the view type.height
,top
,center.y
, andbottom
unspecifiedChild entered vertically in the parent and uses the default height calculation for the child view type. Horizontal positioning works like vertical positioning, except that the precedence is
width
,left
,center.x
,right
.For complete details on composite layout rules, see Transitioning to the New UI Layout System in the Titanium Mobile Guides.
-
vertical
. Children are laid out vertically from top to bottom. The first child is laid outtop
units from its parent's bounding box. Each subsequent child is laid out below the previous child. The space between children is equal to the upper child'sbottom
value plus the lower child'stop
value.Each child is positioned horizontally as in the composite layout mode.
-
horizontal
. Horizontal layouts have different behavior depending on whether wrapping is enabled. Wrapping is enabled by default (thehorizontalWrap
property istrue
).With wrapping behavior, the children are laid out horizontally from left to right, in rows. If a child requires more horizontal space than exists in the current row, it is wrapped to a new row. The height of each row is equal to the maximum height of the children in that row.
Wrapping behavior is available on iOS and Android. When the
horizontalWrap
property is set to true, the first row is placed at the top of the parent view, and successive rows are placed below the first row. Each child is positioned vertically within its row somewhat like composite layout mode. In particular:- If neither
top
orbottom
is specified, the child is centered in the row. - If either
top
orbottom
is specified, the child is aligned to either the top or bottom of the row, with the specified amount of padding. - If both
top
andbottom
is specified for a given child, the properties are both treated as padding.
If the
horizontalWrap
property is false, the behavior is more equivalent to a vertical layout. Children are laid or horizontally from left to right in a single row. Theleft
andright
properties are used as padding between the children, and thetop
andbottom
properties are used to position the children vertically.Defaults to Composite layout.
- If neither
# left
View's left position, in platform-specific units.
This position is relative to the view's parent. Exact interpretation depends on the parent view's layout property. Can be either a float value or a dimension string (for example, '50%' or '10px').
This is an input property for specifying where the view should be positioned, and does not represent the view's calculated position.
Defaults to undefined
.
# lifecycleContainer
The Window or TabGroup whose Activity lifecycle should be triggered on the proxy.
If this property is set to a Window or TabGroup, then the corresponding Activity lifecycle event callbacks will also be called on the proxy. Proxies that require the activity lifecycle will need this property set to the appropriate containing Window or TabGroup.
# opacity
Opacity of this view, from 0.0 (transparent) to 1.0 (opaque). Defaults to 1.0 (opaque).
# overrideCurrentAnimation CREATION ONLY
When on, animate call overrides current animation if applicable.
If this property is set to false, the animate call is ignored if the view is currently being animated.
Defaults to undefined
but behaves as false
# preventDefaultImage
Prevent the default image from being displayed while loading a remote image. This property
is ignored when the defaultImage
property is set.
Default: false
# previewContext
The preview context used in the 3D-Touch feature "Peek and Pop".
Preview context to present the "Peek and Pop" of a view. Use an configured instance of Titanium.UI.iOS.PreviewContext here.
Note: This property can only be used on devices running iOS9 or later and supporting 3D-Touch. It is ignored on older devices and can manually be checked using forceTouchSupported.
# pullBackgroundColor
Background color of the wrapper view when this view is used as either pullView or headerPullView.
Defaults to undefined
. Results in a light grey background color on the wrapper view.
# rect READONLY
The bounding box of the view relative to its parent, in system units.
The view's bounding box is defined by its size and position.
The view's size is rect.width
x rect.height
. The view's top-left position relative to
its parent is (rect.x
, rect.y
).
On Android it will also return rect.absoluteX
and 'rect.absoluteY' which are relative to
the main window.
The correct values will only be available when layout is complete. To determine when layout is complete, add a listener for the postlayout event.
# repeatCount
Number of times to repeat the image animation.
Default: 0 (infinite)
# right
View's right position, in platform-specific units.
This position is relative to the view's parent. Exact interpretation depends on the parent view's layout property. Can be either a float value or a dimension string (for example, '50%' or '10px').
This is an input property for specifying where the view should be positioned, and does not represent the view's calculated position.
Defaults to undefined
.
# rotation
Clockwise 2D rotation of the view in degrees.
Translation values are applied to the static post layout value.
# rotationX
Clockwise rotation of the view in degrees (x-axis).
Translation values are applied to the static post layout value.
# rotationY
Clockwise rotation of the view in degrees (y-axis).
Translation values are applied to the static post layout value.
# scaleX
Scaling of the view in x-axis in pixels.
Translation values are applied to the static post layout value.
# scaleY
Scaling of the view in y-axis in pixels.
Translation values are applied to the static post layout value.
# scalingMode
Determines how the image is scaled within the view.
Default: Titanium.Media.IMAGE_SCALING_AUTO
# size READONLY
The size of the view in system units.
Although property returns a Dimension dictionary, only the width
and height
properties are valid. The position properties--x
and y
--are always 0.
To find the position and size of the view, use the rect property instead.
The correct values will only be available when layout is complete. To determine when layout is complete, add a listener for the postlayout event.
# softKeyboardOnFocus
Determines keyboard behavior when this view is focused. Defaults to SOFT_KEYBOARD_DEFAULT_ON_FOCUS.