Drawable Resources

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Drawable Resources

@H_404_3@ @H_404_3@

See also

  1. 2D Graphics

A drawable resource is a general concept for a graphic that canbe drawn to the screen and which you can retrieve with APIs such asgetDrawable(int) or apply to another XML resource withattributes such as android:drawable andandroid:icon. There are several different types ofdrawables:

Bitmap File

A bitmap graphic file ( .png,.jpg,or .gif). Creates a BitmapDrawable.
Nine-Patch File
A PNG file with stretchable regions to allow image resizingbased on content ( .9.png). Creates a NinePatchDrawable.
Layer List
A Drawable that manages an array of other Drawables. These aredrawn in array order,so the element with the largest index is bedrawn on top. Creates a LayerDrawable.
State List
An XML file that references different bitmap graphics fordifferent states (for example,to use a different image when abutton is pressed). Creates a StateListDrawable.
Level List
An XML file that defines a drawable that manages a number ofalternate Drawables,each assigned a maximum numerical value.Creates a LevelListDrawable.
Transition Drawable
An XML file that defines a drawable that can cross-fade betweentwo drawable resources. Creates a TransitionDrawable.
Inset Drawable
An XML file that defines a drawable that insets anotherdrawable by a specified distance. This is useful when a View needsa background drawble that is smaller than the View's actualbounds.
Clip Drawable
An XML file that defines a drawable that clips another Drawablebased on this Drawable's current level value. Creates a ClipDrawable.
Scale Drawable
An XML file that defines a drawable that changes the size ofanother Drawable based on its current level value. Creates a ScaleDrawable
Shape Drawable
An XML file that defines a geometric shape,including colorsand gradients. Creates a ShapeDrawable.

Also see the Animation Resource document for how to create an AnimationDrawable.

Note: A color resource can also be used as a drawable in XML. Forexample,when creating a state list drawable,you can reference a color resource for theandroid:drawable attribute(android:drawable="@color/green").

Bitmap

A bitmap image. Android supports bitmap files in a threeformats: .png (preferred),.jpg(acceptable),.gif (discouraged).

You can reference a bitmap file directly,using the filename asthe resource ID,or create an alias resource ID in XML.

Note: Bitmap files may beautomatically optimized with lossless image compression by theaapt tool. For example,a true-color PNG that does not requiremore than 256 colors may be converted to an 8-bit PNG with a colorpalette. This will result in an image of equal quality but whichrequires less memory. So be aware that the image binaries placed inthis directory can change during the build. If you plan on readingan image as a bit stream in order to convert it to a bitmap,putyour images in the res/raw/ folder instead,where theywill not be optimized.

Bitmap File

A bitmap file is a .png,or.gif file. Android creates a Drawable resource for any of these files when you savethem in the res/drawable/ directory.

file location:
res/drawable/filename.png( .png,or .gif)
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a BitmapDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
example:
With an image saved at res/drawable/myimage.png,this layout XML applies the image to a View: 
<ImageView

  android:layout_height="wrap_content"

  android:layout_width="wrap_content"

  android:src="@drawable/myimage" />

The following application code retrieves the image as aDrawable:

Resources res = ;
Drawable drawable = res.(R.drawable.myimage);
getResources()getDrawable
see also:

XML Bitmap

An XML bitmap is a resource defined in XML that points to abitmap file. The effect is an alias for a raw bitmap file. The XMLcan specify additional properties for the bitmap such as ditheringand tiling.

Note: You can use a<bitmap> element as achild of an <item>element. For example,when creating a state list or layer list,you can exclude the android:drawableattribute from an <item>element and nest a<bitmap> inside it thatdefines the drawable item.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a BitmapDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<bitmap

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:src="@[package:]drawable/drawable_resource"

  android:antialias=["true" | "false"]

  android:dither=["true" | "false"]

  android:filter=["true" | "false"]

  android:gravity=["top" | "bottom" | "left" | "right" | "center_vertical" |

           "fill_vertical" | "center_horizontal" | "fill_horizontal" |

           "center" | "fill" | "clip_vertical" | "clip_horizontal"]

  android:tileMode=["disabled" | "clamp" | "repeat" | "mirror"] />
elements:
<bitmap>
Defines the bitmap source and its properties.

attributes:

xmlns:android
String. Defines the XML namespace,which must be "http://schemas.android.com/apk/res/android". This isrequired only if the <bitmap> is the rootelement—it is not needed when the <bitmap> is nestedinside an <item>.
android:src
Drawable resource. required.Reference to a drawable resource.
android:antialias
Boolean. Enables or disables antialiasing.
android:dither
Boolean. Enables or disables dithering of the bitmapif the bitmap does not have the same pixel configuration as thescreen (for instance: a ARGB 8888 bitmap with an RGB 565screen).
android:filter
Boolean. Enables or disables bitmap filtering.Filtering is used when the bitmap is shrunk or stretched to smoothits apperance.
android:gravity
Keyword. Defines the gravity for the bitmap. Thegravity indicates where to position the drawable in its containerif the bitmap is smaller than the container.

Must be one or more (separated by '|') of the following constantvalues:

Value Description
top Put the object at the top of its container,not changing itssize.
bottom Put the object at the bottom of its container,not changing itssize.
left Put the object at the left edge of its container,not changingits size.
right Put the object at the right edge of its container,not changingits size.
center_vertical Place object in the vertical center of its container,notchanging its size.
fill_vertical Grow the vertical size of the object if needed so it completelyfills its container.
center_horizontal Place object in the horizontal center of its container,notchanging its size.
fill_horizontal Grow the horizontal size of the object if needed so itcompletely fills its container.
center Place the object in the center of its container in both thevertical and horizontal axis,not changing its size.
fill Grow the horizontal and vertical size of the object if neededso it completely fills its container. This is the default.
clip_vertical Additional option that can be set to have the top and/or bottomedges of the child clipped to its container's bounds. The clip isbased on the vertical gravity: a top gravity clips the bottom edge,a bottom gravity clips the top edge,and neither clips bothedges.
clip_horizontal Additional option that can be set to have the left and/or rightedges of the child clipped to its container's bounds. The clip isbased on the horizontal gravity: a left gravity clips the rightedge,a right gravity clips the left edge,and neither clips bothedges.
android:tileMode
Keyword. Defines the tile mode. When the tile mode isenabled,the bitmap is repeated. Gravity is ignored when the tilemode is enabled.

Must be one of the following constant values:

Value Description
disabled Do not tile the bitmap. This is the default value.
clamp Replicates the edge color if the shader draws outside of itsoriginal bounds
repeat Repeats the shader's image horizontally and vertically.
mirror Repeats the shader's image horizontally and vertically,alternating mirror images so that adjacent images always seam.
example: 
<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"

  android:src="@drawable/icon"

  android:tileMode="repeat" />
see also:

Nine-Patch

A NinePatch is a PNG image in which you can definestretchable regions that Android scales when content within theView exceeds the normal image bounds. You typically assign thistype of image as the background of a View that has at least onedimension set to "wrap_content",and when the Viewgrows to accomodate the content,the Nine-Patch image is alsoscaled to match the size of the View. An example use of aNine-Patch image is the background used by Android's standardButton widget,which must stretch to accommodate thetext (or image) inside the button.

Same as with a normal bitmap,you can reference a Nine-Patch file directly or from aresource defined by XML.

For a complete discussion about how to create a Nine-Patch filewith stretchable regions,see the 2D Graphics document.

Nine-Patch File

file location:
res/drawable/filename.9.png
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a NinePatchDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
example:
With an image saved at res/drawable/myninepatch.9.png,this layout XMLapplies the Nine-Patch to a View: 
<Button

  android:layout_height="wrap_content"

  android:layout_width="wrap_content"

  android:background="@drawable/myninepatch" />
see also:

XML Nine-Patch

An XML Nine-Patch is a resource defined in XML that points to aNine-Patch file. The XML can specify dithering for the image.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a NinePatchDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<nine-patch

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:src="@[package:]drawable/drawable_resource"

  android:dither=["true" | "false"] />
elements:
<nine-patch>
Defines the Nine-Patch source and its properties.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:src
Drawable resource. required.Reference to a Nine-Patch file.
android:dither
Boolean. Enables or disables dithering of the bitmapif the bitmap does not have the same pixel configuration as thescreen (for instance: a ARGB 8888 bitmap with an RGB 565screen).
example: 
<?xml version="1.0" encoding="utf-8"?>
<nine-patch xmlns:android="http://schemas.android.com/apk/res/android"

  android:src="@drawable/myninepatch"

  android:dither="false" />

Layer List

A LayerDrawable is a drawable object that manages an arrayof other drawables. Each drawable in the list is drawn in the orderof the list—the last drawable in the list is drawn on top.

Each drawable is represented by an<item> element inside asingle <layer-list>element.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a LayerDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<layer-list

  xmlns:android="http://schemas.android.com/apk/res/android" >

  <item

    android:drawable="@[package:]drawable/drawable_resource"

    android:id="@[+][package:]id/resource_name"

    android:top="dimension"

    android:right="dimension"

    android:bottom="dimension"

    android:left="dimension" />
</layer-list>
elements:
<layer-list>
required. This must be the root element.Contains one or more <item> elements.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
<item>
Defines a drawable to place in the layer drawable,in aposition defined by its attributes. Must be a child of a <selector> element.Accepts child <bitmap>elements.

attributes:

android:drawable
Drawable resource. required.Reference to a drawable resource.
android:id
Resource ID. A unique resource ID for this drawable.To create a new resource ID for this item,use the form: "@+id/name". The plus symbol indicates thatthis should be created as a new ID. You can use this identifier toretrieve and modify the drawable with View.findViewById() or Activity.findViewById().
android:top
Integer. The top offset in pixels.
android:right
Integer. The right offset in pixels.
android:bottom
Integer. The bottom offset in pixels.
android:left
Integer. The left offset in pixels.

All drawable items are scaled to fit the size of the containingView,by default. Thus,placing your images in a layer list atdifferent positions might increase the size of the View and someimages scale as appropriate. To avoid scaling items in the list,use a <bitmap> elementinside the <item>element to specify the drawable and define the gravity to somethingthat does not scale,such as "center". For example,the following <item>defines an item that scales to fit its container View:

<item android:drawable="@drawable/image" />

To avoid scaling,the following example uses a<bitmap> element withcentered gravity:

<item>

 <bitmap android:src="@drawable/image"

     android:gravity="center" />
</item>
example:
XML file saved at res/drawable/layers.xml: 
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

  <item>

   <bitmap android:src="@drawable/android_red"

    android:gravity="center" />

  </item>

  <item android:top="10dp" android:left="10dp">

   <bitmap android:src="@drawable/android_green"

    android:gravity="center" />

  </item>

  <item android:top="20dp" android:left="20dp">

   <bitmap android:src="@drawable/android_blue"

    android:gravity="center" />

  </item>
</layer-list>

Notice that this example uses a nested<bitmap> element todefine the drawable resource for each item with a "center" gravity.This ensures that none of the images are scaled to fit the size ofthe container,due to resizing caused by the offset images.

This layout XML applies the drawable to a View:

<ImageView

  android:layout_height="wrap_content"

  android:layout_width="wrap_content"

  android:src="@drawable/layers" />

The result is a stack of increasingly offset images:

see also:

State List

A StateListDrawable is a drawable object defined in XMLthat uses a several different images to represent the same graphic,depending on the state of the object. For example,a Button widget can exist in one of several differentstates (pressed,focused,or niether) and,using a state listdrawable,you can provide a different background image for eachstate.

You can describe the state list in an XML file. Each graphic isrepresented by an <item>element inside a single<selector> element. Each<item> uses varIoUsattributes to describe the state in which it should be used as thegraphic for the drawable.

During each state change,the state list is traversed top tobottom and the first item that matches the current state isused—the selection is not based on the "best match," butsimply the first item that meets the minimum criteria of thestate.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a StateListDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"

  android:constantSize=["true" | "false"]

  android:dither=["true" | "false"]

  android:variablePadding=["true" | "false"] >

  <item

    android:drawable="@[package:]drawable/drawable_resource"

    android:state_pressed=["true" | "false"]

    android:state_focused=["true" | "false"]

    android:state_selected=["true" | "false"]

    android:state_checkable=["true" | "false"]

    android:state_checked=["true" | "false"]

    android:state_enabled=["true" | "false"]

    android:state_window_focused=["true" | "false"] />
</selector>
elements:
<selector>
required. This must be the root element.Contains one or more <item> elements.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:constantSize
Boolean. "true" if the drawable's reported internalsize remains constant as the state changes (the size is the maximumof all of the states); "false" if the size varies based on thecurrent state. Default is false.
android:dither
Boolean. "true" to enable dithering of the bitmap ifthe bitmap does not have the same pixel configuration as the screen(for instance,an ARGB 8888 bitmap with an RGB 565 screen); "false"to disable dithering. Default is true.
android:variablePadding
Boolean. "true" if the drawable's padding shouldchange based on the current state that is selected; "false" if thepadding should stay the same (based on the maximum padding of allthe states). Enabling this feature requires that you deal withperforming layout when the state changes,which is often notsupported. Default is false.
<item>
Defines a drawable to use during certain states,as describedby its attributes. Must be a child of a <selector> element.

attributes:

android:drawable
Drawable resource. required.Reference to a drawable resource.
android:state_pressed
Boolean. "true" if this item should be used when theobject is pressed (such as when a button is touched/clicked);"false" if this item should be used in the default,non-pressedstate.
android:state_focused
Boolean. "true" if this item should be used when theobject is focused (such as when a button is highlighted using thetrackball/d-pad); "false" if this item should be used in thedefault,non-focused state.
android:state_selected
Boolean. "true" if this item should be used when theobject is selected (such as when a tab is opened); "false" if thisitem should be used when the object is not selected.
android:state_checkable
Boolean. "true" if this item should be used when theobject is checkable; "false" if this item should be used when theobject is not checkable. (Only useful if the object can transitionbetween a checkable and non-checkable widget.)
android:state_checked
Boolean. "true" if this item should be used when theobject is checked; "false" if it should be used when the object isun-checked.
android:state_enabled
Boolean. "true" if this item should be used when theobject is enabled (capable of receiving touch/click events);"false" if it should be used when the object is disabled.
android:state_window_focused
Boolean. "true" if this item should be used when theapplication window has focus (the application is in theforeground),"false" if this item should be used when theapplication window does not have focus (for example,if thenotification shade is pulled down or a dialog appears).

Note: Remember that Androidapplies the first item in the state list that matches the currentstate of the object. So,if the first item in the list containsnone of the state attributes above,then it is applied every time,which is why your default value should always be last (asdemonstrated in the following example).

example:
XML file saved at res/drawable/button.xml: 
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:state_pressed="true"

     android:drawable="@drawable/button_pressed" /> <!-- pressed -->

  <item android:state_focused="true"

     android:drawable="@drawable/button_focused" /> <!-- focused -->

  <item android:drawable="@drawable/button_normal" /> <!-- default -->
</selector>

This layout XML applies the state list drawable to a Button:

<Button

  android:layout_height="wrap_content"

  android:layout_width="wrap_content"

  android:background="@drawable/button" />
see also:

Level List

A Drawable that manages a number of alternate Drawables,eachassigned a maximum numerical value. Setting the level value of thedrawable with setLevel() loads the drawable resource in the level listthat has a android:maxLevel value greater than orequal to the value passed to the method.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a LevelListDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<level-list

  xmlns:android="http://schemas.android.com/apk/res/android" >

  <item

    android:drawable="@drawable/drawable_resource"

    android:maxLevel="integer"

    android:minLevel="integer" />
</level-list>
elements:
<level-list>
This must be the root element. Contains one or more <item> elements.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
<item>
Defines a drawable to use at a certain level.

attributes:

android:drawable
Drawable resource. required.Reference to a drawable resource to be inset.
android:maxLevel
Integer. The maximum level allowed for this item.
android:minLevel
Integer. The minimum level allowed for this item.
example: 
<?xml version="1.0" encoding="utf-8"?>
<level-list xmlns:android="http://schemas.android.com/apk/res/android" >

  <item

    android:drawable="@drawable/status_off"

    android:maxLevel="0" />

  <item

    android:drawable="@drawable/status_on"

    android:maxLevel="1" />
</level-list>

Once this is applied to a View,the level can be changed with setLevel() or setImageLevel().

see also:

Transition Drawable

A TransitionDrawable is a drawable object that cancross-fade between the two drawable resources.

Each drawable is represented by an<item> element inside asingle <transition>element. No more than two items are supported. To transitionforward,call startTransition(). To transition backward,callreverseTransition().

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a TransitionDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<transition
xmlns:android="http://schemas.android.com/apk/res/android" >

  <item

    android:drawable="@[package:]drawable/drawable_resource"

    android:id="@[+][package:]id/resource_name"

    android:top="dimension"

    android:right="dimension"

    android:bottom="dimension"

    android:left="dimension" />
</transition>
elements:
<transition>
required. This must be the root element.Contains one or more <item> elements.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
<item>
Defines a drawable to use as part of the drawable transition.Must be a child of a <transition> element.Accepts child <bitmap>elements.

attributes:

android:drawable
Drawable resource. required.Reference to a drawable resource.
android:id
Resource ID. A unique resource ID for this drawable.To create a new resource ID for this item,use the form: "@+id/name". The plus symbol indicates thatthis should be created as a new ID. You can use this identifier toretrieve and modify the drawable with View.findViewById() or Activity.findViewById().
android:top
Integer. The top offset in pixels.
android:right
Integer. The right offset in pixels.
android:bottom
Integer. The bottom offset in pixels.
android:left
Integer. The left offset in pixels.
example:
XML file saved at res/drawable/transition.xml: 
<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:drawable="@drawable/on" />

  <item android:drawable="@drawable/off" />
</transition>

This layout XML applies the drawable to a View:

<ImageButton

  android:id="@+id/button"

  android:layout_height="wrap_content"

  android:layout_width="wrap_content"

  android:src="@drawable/transition" />

And the following code performs a 500ms transition from thefirst item to the second:

ImageButton button = (ImageButton) findViewById(R.id.button);
TransitionDrawable drawable = (TransitionDrawable) button.getDrawable();

drawable.startTransition(500);
see also:

Inset Drawable

A drawable defined in XML that insets another drawable by aspecified distance. This is useful when a View needs a backgroundthat is smaller than the View's actual bounds.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a InsetDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<inset

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/drawable_resource"

  android:insetTop="dimension"

  android:insetRight="dimension"

  android:insetBottom="dimension"

  android:insetLeft="dimension" />
elements:
<inset>
Defines the inset drawable. This must be the root element.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:drawable
Drawable resource. required.Reference to a drawable resource to be inset.
android:insetTop
Dimension. The top inset,as a dimension value or dimension resource
android:insetRight
Dimension. The right inset,as a dimension value or dimension resource
android:insetBottom
Dimension. The bottom inset,as a dimension value or dimension resource
android:insetLeft
Dimension. The left inset,as a dimension value or dimension resource
example: 
<?xml version="1.0" encoding="utf-8"?>
<inset xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/background"

  android:insetTop="10dp"

  android:insetLeft="10dp" />
see also:

Clip Drawable

A drawable defined in XML that clips another drawable based onthis Drawable's current level. You can control how much the childdrawable gets clipped in width and height based on the level,aswell as a gravity to control where it is placed in its overallcontainer. Most often used to implement things like progressbars.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a ClipDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<clip

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/drawable_resource"

  android:clipOrientation=["horizontal" | "vertical"]

  android:gravity=["top" | "bottom" | "left" | "right" | "center_vertical" |

          "fill_vertical" | "center_horizontal" | "fill_horizontal" |

          "center" | "fill" | "clip_vertical" | "clip_horizontal"] />
elements:
<clip>
Defines the clip drawable. This must be the root element.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:drawable
Drawable resource. required.Reference to a drawable resource to be clipped.
android:clipOrientation
Keyword. The orientation for the clip.

Must be one of the following constant values:

Value Description
horizontal Clip the drawable horizontally.
vertical Clip the drawable vertically.
android:gravity
Keyword. Specifies where to clip within the drawable.

Must be one or more (separated by '|') of the following constantvalues:

Value Description
top Put the object at the top of its container,not changing itssize. When clipOrientation is "vertical",clipping occurs at the bottom of the drawable.
bottom Put the object at the bottom of its container,clipping occurs at the top of the drawable.
left Put the object at the left edge of its container,not changingits size. This is the default. When clipOrientation is"horizontal",clipping occurs at the right side of thedrawable. This is the default.
right Put the object at the right edge of its container,not changingits size. When clipOrientation is"horizontal",clipping occurs at the left side of thedrawable.
center_vertical Place object in the vertical center of its container,notchanging its size. Clipping behaves the same as when gravity is"center".
fill_vertical Grow the vertical size of the object if needed so it completelyfills its container. When clipOrientation is"vertical",no clipping occurs because the drawablefills the vertical space (unless the drawable level is 0,in whichcase it's not visible).
center_horizontal Place object in the horizontal center of its container,notchanging its size. Clipping behaves the same as when gravity is"center".
fill_horizontal Grow the horizontal size of the object if needed so itcompletely fills its container. When clipOrientationis "horizontal",no clipping occurs because thedrawable fills the horizontal space (unless the drawable level is0,in which case it's not visible).
center Place the object in the center of its container in both thevertical and horizontal axis,not changing its size. WhenclipOrientation is "horizontal",clippingoccurs on the left and right. When clipOrientation is"vertical",clipping occurs on the top andbottom.
fill Grow the horizontal and vertical size of the object if neededso it completely fills its container. No clipping occurs becausethe drawable fills the horizontal and vertical space (unless thedrawable level is 0,in which case it's not visible).
clip_vertical Additional option that can be set to have the top and/or bottomedges of the child clipped to its container's bounds. The clip isbased on the vertical gravity: a top gravity clips the bottom edge,and neither clips bothedges.
example:
XML file saved at res/drawable/clip.xml: 
<?xml version="1.0" encoding="utf-8"?>
<clip xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/android"

  android:clipOrientation="horizontal"

  android:gravity="left" />
</clip>

The following layout XML applies the clip drawable to aView:

<ImageView

  android:id="@+id/image"

  android:background="@drawable/clip"

  android:layout_height="wrap_content"

  android:layout_width="wrap_content" />

The following code gets the drawable and increases the amount ofclipping in order to progressively reveal the image:

ImageView imageview = (ImageView) findViewById(R.id.image);
ClipDrawable drawable = (ClipDrawable) imageview.getDrawable();

drawable.setLevel(drawable.getLevel() + 1000);

Increasing the level reduces the amount of clipping and slowlyreveals the image. Here it is at a level of 7000:

Note: The default level is 0,which is fully clipped so the image is not visible. When the levelis 10,000,the image is not clipped and completely visible.

see also:

Scale Drawable

A drawable defined in XML that changes the size of anotherdrawable based on its current level.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a ScaleDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<scale

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/drawable_resource"

  android:scaleGravity=["top" | "bottom" | "left" | "right" | "center_vertical" |

             "fill_vertical" | "center_horizontal" | "fill_horizontal" |

             "center" | "fill" | "clip_vertical" | "clip_horizontal"]

  android:scaleHeight="percentage"

  android:scaleWidth="percentage" />
elements:
<scale>
Defines the scale drawable. This must be the root element.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:drawable
Drawable resource. required.Reference to a drawable resource.
android:scaleGravity
Keyword. Specifies the gravity position after scaling.

Must be one or more (separated by '|') of the following constantvalues:

Value Description
top Put the object at the top of its container,not changingits size. This is the default.
right Put the object at the right edge of its container,not changing its size.
fill Grow the horizontal and vertical size of the object if neededso it completely fills its container.
clip_vertical Additional option that can be set to have the top and/or bottomedges of the child clipped to its container's bounds. The clip isbased on the vertical gravity: a top gravity clips the bottom edge,and neither clips bothedges.
android:scaleHeight
Percentage. The scale height,expressed as apercentage of the drawable's bound. The value's format is XX%. Forinstance: 100%,12.5%,etc.
android:scaleWidth
Percentage. The scale width,expressed as a percentageof the drawable's bound. The value's format is XX%. For instance:100%,etc.
example: 
<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"

  android:drawable="@drawable/@R_301_395@"

  android:scaleGravity="center_vertical|center_horizontal"

  android:scaleHeight="80%"

  android:scaleWidth="80%" />
see also:

Shape Drawable

This is a generic shape defined in XML.

file location:
res/drawable/filename.xml
The filename is used as the resource ID.
compiled resource datatype:
Resource pointer to a ShapeDrawable.
resource reference:
In Java: R.drawable.filename
In XML: @[package:]drawable/filename
Syntax: 
<?xml version="1.0" encoding="utf-8"?>
<shape

  xmlns:android="http://schemas.android.com/apk/res/android"

  android:shape=["rectangle" | "oval" | "line" | "ring"] >

  <corners

    android:radius="integer"

    android:topLeftRadius="integer"

    android:topRightRadius="integer"

    android:bottomLeftRadius="integer"

    android:bottomRightRadius="integer" />

  <gradient

    android:angle="integer"

    android:centerX="integer"

    android:centerY="integer"

    android:centerColor="integer"

    android:endColor="color"

    android:gradientRadius="integer"

    android:startColor="color"

    android:type=["linear" | "radial" | "sweep"]

    android:usesLevel=["true" | "false"] />

  <padding

    android:left="integer"

    android:top="integer"

    android:right="integer"

    android:bottom="integer" />

  <size

    android:width="integer"

    android:color="color"

    android:dashWidth="integer"

    android:dashGap="integer" />

  <solid

    android:color="color" />

  <stroke

    android:width="integer"

    android:color="color"

    android:dashWidth="integer"

    android:dashGap="integer" />
</shape>
elements:
<shape>
The shape drawable. This must be the root element.

attributes:

xmlns:android
String. required. Defines the XMLnamespace,which must be "http://schemas.android.com/apk/res/android".
android:shape
Keyword. Defines the type of shape. Valid values are:
Value Desciption
"rectangle" A rectangle that fills the containing View. This is the defaultshape.
"oval" An oval shape that fits the dimensions of the containingView.
"line" A horizontal line that spans the width of the containing View.This shape requires the<stroke> element todefine the width of the line.
"ring" A ring shape.

The following attributes are used only whenandroid:shape="ring":

android:innerRadius
Dimension. The radius for the inner part of the ring(the hole in the middle),as a dimension value or dimension resource.
android:innerRadiusRatio
Float. The radius for the inner part of the ring,expressed as a ratio of the ring's width. For instance,if android:innerRadiusRatio="5",then the inner radiusequals the ring's width divided by 5. This value is overridden by android:innerRadius. Default value is 9.
android:thickness
Dimension. The thickness of the ring,as a dimensionvalue or dimension resource.
android:thicknessRatio
Float. The thickness of the ring,expressed as a ratioof the ring's width. For instance,if android:thicknessRatio="2",then the thickness equalsthe ring's width divided by 2. This value is overridden by android:innerRadius. Default value is 3.
android:useLevel
Boolean. "true" if this is used as a LevelListDrawable. This should normally be "false" oryour shape may not appear.
<corners>
Creates rounded corners for the shape. Applies only when theshape is a rectangle.

attributes:

android:radius
Dimension. The radius for all corners,as a dimensionvalue or dimension resource. This is overridden for each corner by thefollowing attributes.
android:topLeftRadius
Dimension. The radius for the top-left corner,as adimension value or dimension resource.
android:topRightRadius
Dimension. The radius for the top-right corner,as adimension value or dimension resource.
android:bottomLeftRadius
Dimension. The radius for the bottom-left corner,as adimension value or dimension resource.
android:bottomRightRadius
Dimension. The radius for the bottom-right corner,asa dimension value or dimension resource.

Note: Every corner must(initially) be provided a corner radius greater than 1,or else nocorners are rounded. If you want specific corners to notbe rounded,a work-around is to use android:radius toset a default corner radius greater than 1,but then override eachand every corner with the values you really want,providing zero("0dp") where you don't want rounded corners.

<gradient>
Specifies a gradient color for the shape.

attributes:

android:angle
Integer. The angle for the gradient,in degrees. 0 isleft to right,90 is bottom to top. It must be a multiple of 45.Default is 0.
android:centerX
Float. The relative X-position for the center of thegradient (0 - 1.0). Does not apply when android:type="linear".
android:centerY
Float. The relative Y-position for the center of thegradient (0 - 1.0). Does not apply when android:type="linear".
android:centerColor
Color. Optional color that comes between the start andend colors,as a hexadecimal value or color resource.
android:endColor
Color. The ending color,as a hexadecimal value or color resource.
android:gradientRadius
Float. The radius for the gradient. Only applied when android:type="radial".
android:startColor
Color. The starting color,as a hexadecimal value or color resource.
android:type
Keyword. The type of gradient pattern to apply. Validvalues are:
Value Description
"linear" A linear gradient. This is the default.
"radial" A radial gradient. The start color is the center color.
"sweep" A sweeping line gradient.
android:useLevel
Boolean. "true" if this is used as a LevelListDrawable.
<padding>
Padding to apply to the containing View element (this pads theposition of the View content,not the shape).

attributes:

android:left
Dimension. Left padding,as a dimension value or dimension resource.
android:top
Dimension. Top padding,as a dimension value or dimension resource.
android:right
Dimension. Right padding,as a dimension value or dimension resource.
android:bottom
Dimension. Bottom padding,as a dimension value or dimension resource.
<size>
The size of the shape.

attributes:

android:height
Dimension. The height of the shape,as a dimensionvalue or dimension resource.
android:width
Dimension. The width of the shape,as a dimensionvalue or dimension resource.

Note: The shape scales to the sizeof the container View proportionate to the dimensions defined here,by default. When you use the shape in an ImageView,you can restrict scaling by setting theandroid:scaleType to "center".

<solid>
A solid color to fill the shape.

attributes:

android:color
Color. The color to apply to the shape,as ahexadecimal value or color resource.
<stroke>
A stroke line for the shape.

attributes:

android:width
Dimension. The thickness of the line,as a dimensionvalue or dimension resource.
android:color
Color. The color of the line,as a hexadecimal valueor color resource.
android:dashGap
Dimension. The distance between line dashes,as adimension value or dimension resource. Only valid if android:dashWidth is set.
android:dashWidth
Dimension. The size of each dash line,as a dimensionvalue or dimension resource. Only valid if android:dashGapis set.
example:
XML file saved at res/drawable/gradient_Box.xml: 
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"

  android:shape="rectangle">

  <gradient

    android:startColor="#FFFF0000"

    android:endColor="#80FF00FF"

    android:angle="45"/>

  <padding android:left="7dp"

    android:top="7dp"

    android:right="7dp"

    android:bottom="7dp" />

  <corners android:radius="8dp" />
</shape>

This layout XML applies the shape drawable to a View:

<TextView

  android:background="@drawable/gradient_Box"

  android:layout_height="wrap_content"

  android:layout_width="wrap_content" />

This application code gets the shape drawable and applies it toa View:

Resources res = ;
Drawable shape = res. (R.drawable.gradient_Box);


TextView tv = (TextView)findViewByID(R.id.textview);

tv.setBackground(shape);
getResources()getDrawable
原文链接：https://www.f2er.com/xml/298137.html

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