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Android的资源类型之Drawable

2016-07-13 18:17 459 查看

Drawable资源概述：

一种可以通过getDrawable(int)方法获取到的，或者可以通过android:drawable和android:icon属性应用到XML文件的资源。个人理解，可以转成Drawable对象的资源。

Drawable资源分类：

可当做drawable处理的资源有一下几类：

1、图片文件，包括.9图片文件。

2、LayerDrawable类，或者以<layer-list>为根节点，<item>为子节点的xml文件。

如：ProgressBar的一级进度色和二级进度色，用的就是这种资源。

3、StateListDrawable类，或者以<selector>为根节点，<item>为子节点的xml文件。<item>节点内通过android:state_pressed等属性判断该item的显示与否。

如：按钮的点击效果。

4、LevelListDrawable类，或者以<level-list>为根节点，<item>为子节点的xml文件。<item>节点内通过android:maxLevel属性判断等级范围来决定item的显示与否。

如：活动类型图标，可通过ImageView的setImageLevel方法，通过设置等级来显示不同图标。

5、TransitionDrawable类，或者以<transition>为根节点，<item>为子节点的XML文件。通过TransitionDrawable的startTransition(int seconds)来执行item依次渐变。

如：常用嵌入其他节点使用。

6、InsetDrawable类，或者以<inset>为根节点的XML文件。通过android:insetTop等属性设置距背景图顶部的距离，类似于paddingTop。

如：常用嵌入其他节点使用。

7、ClipDrawable类，或者以<clip>为根节点的XML文件。通过android:clipOrientation等属性设置裁剪方向。

如：ProgressBar的进度条，就是通过裁剪实现的。通过drawable.setLevel设置裁剪，默认level是0，完全裁剪，图片不显示；当level为10,000时，不裁剪。

8、ScaleDrawable类，或者以<scale>为根节点的XML文件。通过android:scaleHeight等属性设置缩放方向和比例。

9、GradientDrawable类，或者以<shape>为根节点，<corners><gradient><padding><size><solid><stroke>为子节点的XML文件。

如：圆角描边的按钮。<solid>表示填充，只能设置颜色；stroke表示描边,可设置粗细和颜色等。

10、AnimationDrawable类，或者以<animation-list>为根节点，<item>为子节点的XML文件。通过animationDrawable.start()方法，依次显示item的图片，俗称帧动画。

如：正在加载的提示动画，每个item设置的android:duration为50的话，那么表示每秒加载20帧。而电视机播放的动画影片，不过每秒25帧左右，每帧对应一张图画。

<gradient>元素属性解释：

android:angle integer 渐变梯度的角度，以度为单位。0表示从左至右渐变，90表示从下至上渐变。该值需为45的倍数，默认为0。

android:centerX Float 渐变梯度(0~1.0)的中心位置的X坐标。

android:centerY Float 渐变梯度(0~1.0)的中心位置的Y坐标。

Drawable Resources

Bitmap

A bitmap image. Android supports bitmap files in three formats:

.png

(preferred),

.jpg

(acceptable),

.gif

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

Note: Bitmap files may be automatically optimized with lossless image compression by the

aapt

tool during the build process. For example, a true-color PNG that does not require more than 256 colors may be converted to
an 8-bit PNG with a color palette. This will result in an image of equal quality but which requires less memory. So be aware that the image binaries placed in this directory can change during the build. If you plan on reading an image as a bit stream in order
to convert it to a bitmap, put your images in the

res/raw/

folder instead, where they will not be optimized.

Bitmap File

A bitmap file is a

.png

.jpg

, or

.gif

file. Android creates a

Drawable

resource
for any of these files when you save them in the

res/drawable/

directory.
FILE LOCATION:

res/drawable/filename.png

(

.png

.jpg

, 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 a

Drawable

Resources res = [code]getResources()

;
Drawable drawable = res.

getDrawable

(R.drawable.myimage);[/code]
SEE ALSO:

2D Graphics

BitmapDrawable

XML Bitmap

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

Note: You can use a

<bitmap>

element as a child of an

<item>

element. For example, when creating a state
list or layer list, you can exclude the

android:drawable

attribute
from an

<item>

element and nest a

<bitmap>

inside it that defines 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:mipMap=["true" | "false"]
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 is required only if the

<bitmap>

is the root element—it is not needed
when the

<bitmap>

is nested inside 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 bitmap if the bitmap does not have the same pixel configuration as the screen (for instance: a ARGB 8888 bitmap with an RGB 565 screen).

android:filter

Boolean. Enables or disables bitmap filtering. Filtering is used when the bitmap is shrunk or stretched to smooth its apperance.

android:gravity

Keyword. Defines the gravity for the bitmap. The gravity indicates where to position the drawable in its container if the bitmap is smaller than the container.
Must be one or more (separated by '|') of the following constant values:

Value	Description
top	Put the object at the top of its container, not changing its size.
bottom	Put the object at the bottom of its container, not changing its size.
left	Put the object at the left edge of its container, not changing its size.
right	Put the object at the right edge of its container, not changing its size.
center_vertical	Place object in the vertical center of its container, not changing its size.
fill_vertical	Grow the vertical size of the object if needed so it completely fills its container.
center_horizontal	Place object in the horizontal center of its container, not changing its size.
fill_horizontal	Grow the horizontal size of the object if needed so it completely fills its container.
center	Place the object in the center of its container in both the vertical and horizontal axis, not changing its size.
fill	Grow the horizontal and vertical size of the object if needed so it completely fills its container. This is the default.
clip_vertical	Additional option that can be set to have the top and/or bottom edges of the child clipped to its container's bounds. The clip is based on the vertical gravity: a top gravity clips the bottom edge, a bottom gravity clips the top edge, and neither clips both edges.
clip_horizontal	Additional option that can be set to have the left and/or right edges of the child clipped to its container's bounds. The clip is based on the horizontal gravity: a left gravity clips the right edge, a right gravity clips the left edge, and neither clips both edges.

android:mipMap

Boolean. Enables or disables the mipmap hint. See

setHasMipMap()

for
more information. Default value is false.

android:tileMode

Keyword. Defines the tile mode. When the tile mode is enabled, the bitmap is repeated. Gravity is ignored when the tile mode 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 its original 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:

BitmapDrawable

Creating alias resources

Nine-Patch

NinePatch

is a PNG image in which
you can define stretchable regions that Android scales when content within the View exceeds the normal image bounds. You typically assign this type of image as the background of a View that has at least one dimension set to

"wrap_content"

,
and when the View grows to accomodate the content, the Nine-Patch image is also scaled to match the size of the View. An example use of a Nine-Patch image is the background used by Android's standard

Button

widget,
which must stretch to accommodate the text (or image) inside the button.
Same as with a normal bitmap, you can reference
a Nine-Patch file directly or from a resource defined by XML.
For a complete discussion about how to create a Nine-Patch file with 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 XML applies the Nine-Patch to a View:

<Button
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:background="@drawable/myninepatch" />

XML Nine-Patch

An XML Nine-Patch is a resource defined in XML that points to a Nine-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 XML namespace, 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 bitmap if the bitmap does not have the same pixel configuration as the screen (for instance: a ARGB 8888 bitmap with an RGB 565 screen).

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

LayerDrawable

is a drawable
object that manages an array of other drawables. Each drawable in the list is drawn in the order of the list—the last drawable in the list is drawn on top.
Each drawable is represented by an

<item>

element inside a single

<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 XML namespace, which must be

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

<item>

Defines a drawable to place in the layer drawable, in a position 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 that this should be created as
a new ID. You can use this identifier to retrieve and modify the drawable with

View.findViewById()

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 containing View, by default. Thus, placing your images in a layer list at different positions might increase the size of the View and some images scale as appropriate.
To avoid scaling items in the list, use a

<bitmap>

element inside the

<item>

element to specify the drawable and define the gravity to something that 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 with centered 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 to define the drawable resource for each item with a "center" gravity. This ensures that none of the images are scaled to fit the size
of the 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:

LayerDrawable

State List

StateListDrawable

is
a drawable object defined in XML that 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 different states (pressed, focused, or neither) and, using a state list drawable, you can provide a different background image for each state.
You can describe the state list in an XML file. Each graphic is represented by an

<item>

element inside a single

<selector>

element. Each

<item>

uses
various attributes to describe the state in which it should be used as the graphic for the drawable.
During each state change, the state list is traversed top to bottom and the first item that matches the current state is used—the selection is not based on the "best match," but simply the first item that
meets the minimum criteria of the state.
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_hovered=["true" | "false"]
android:state_selected=["true" | "false"]
android:state_checkable=["true" | "false"]
android:state_checked=["true" | "false"]
android:state_enabled=["true" | "false"]
android:state_activated=["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 XML namespace, which must be

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

android:constantSize

Boolean. "true" if the drawable's reported internal size remains constant as the state changes (the size is the maximum of all of the states); "false" if the size varies based on the current state. Default is false.

android:dither

Boolean. "true" to enable dithering of the bitmap if the 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 should change based on the current state that is selected; "false" if the padding should stay the same (based on the maximum padding of all the states). Enabling this feature
requires that you deal with performing layout when the state changes, which is often not supported. Default is false.

<item>

Defines a drawable to use during certain states, as described by 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 the object is pressed (such as when a button is touched/clicked); "false" if this item should be used in the default, non-pressed state.

android:state_focused

Boolean. "true" if this item should be used when the object has input focus (such as when the user selects a text input); "false" if this item should be used in the default, non-focused state.

android:state_hovered

Boolean. "true" if this item should be used when the object is being hovered by a cursor; "false" if this item should be used in the default, non-hovered state. Often, this drawable may be the same drawable used
for the "focused" state.
Introduced in API level 14.

android:state_selected

Boolean. "true" if this item should be used when the object is the current user selection when navigating with a directional control (such as when navigating through a list with a d-pad); "false" if this item should
be used when the object is not selected.
The selected state is used when focus (

android:state_focused

) is not sufficient (such as when list view has focus and an item within it is selected with a d-pad).

android:state_checkable

Boolean. "true" if this item should be used when the object is checkable; "false" if this item should be used when the object is not checkable. (Only useful if the object can transition between a checkable and non-checkable
widget.)

android:state_checked

Boolean. "true" if this item should be used when the object is checked; "false" if it should be used when the object is un-checked.

android:state_enabled

Boolean. "true" if this item should be used when the object is enabled (capable of receiving touch/click events); "false" if it should be used when the object is disabled.

android:state_activated

Boolean. "true" if this item should be used when the object is activated as the persistent selection (such as to "highlight" the previously selected list item in a persistent navigation view); "false" if it should
be used when the object is not activated.
Introduced in API level 11.

android:state_window_focused

Boolean. "true" if this item should be used when the application window has focus (the application is in the foreground), "false" if this item should be used when the application window does not have focus (for
example, if the notification shade is pulled down or a dialog appears).

Note: Remember that Android applies the first item in the state list that matches the current state of the object. So, if the first item in the list contains none of the state attributes above, then it is applied every time, which is why your
default value should always be last (as demonstrated 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:state_hovered="true"
android:drawable="@drawable/button_focused" /> <!-- hovered -->
<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:

StateListDrawable

Level List

A Drawable that manages a number of alternate Drawables, each assigned a maximum numerical value. Setting the level value of the drawable with

setLevel()

loads
the drawable resource in the level list that has a

android:maxLevel

value greater than or equal 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 XML namespace, 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()

setImageLevel()

.
SEE ALSO:

LevelListDrawable

Transition Drawable

TransitionDrawable

is
a drawable object that can cross-fade between the two drawable resources.
Each drawable is represented by an

<item>

element inside a single

<transition>

element. No more than two items are supported. To transition forward, call

startTransition()

.
To transition backward, call

reverseTransition()

.
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 XML namespace, 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 that this should be created as
a new ID. You can use this identifier to retrieve and modify the drawable with

View.findViewById()

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 the first item to the second:

ImageButton button = (ImageButton) findViewById(R.id.button);
TransitionDrawable drawable = (TransitionDrawable) button.getDrawable();
drawable.startTransition(500);

SEE ALSO:

TransitionDrawable

Inset Drawable

A drawable defined in XML that insets another drawable by a specified distance. This is useful when a View needs a background that 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 XML namespace, 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:

InsetDrawable

Clip Drawable

A drawable defined in XML that clips another drawable based on this Drawable's current level. You can control how much the child drawable gets clipped in width and height based on the level, as well as a gravity
to control where it is placed in its overall container. Most often used to implement things like progress bars.
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 XML namespace, 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 constant values:

Value	Description
top	Put the object at the top of its container, not changing its size. When clipOrientation is "vertical" , clipping occurs at the bottom of the drawable.
bottom	Put the object at the bottom of its container, not changing its size. When clipOrientation is "vertical" , clipping occurs at the top of the drawable.
left	Put the object at the left edge of its container, not changing its size. This is the default. When clipOrientation is "horizontal" , clipping occurs at the right side of the drawable. This is the default.
right	Put the object at the right edge of its container, not changing its size. When clipOrientation is "horizontal" , clipping occurs at the left side of the drawable.
center_vertical	Place object in the vertical center of its container, not changing its size. Clipping behaves the same as when gravity is "center" .
fill_vertical	Grow the vertical size of the object if needed so it completely fills its container. When clipOrientation is "vertical" , no clipping occurs because the drawable fills the vertical space (unless the drawable level is 0, in which case it's not visible).
center_horizontal	Place object in the horizontal center of its container, not changing its size. Clipping behaves the same as when gravity is "center" .
fill_horizontal	Grow the horizontal size of the object if needed so it completely fills its container. When clipOrientation is "horizontal" , no clipping occurs because the drawable fills the horizontal space (unless the drawable level is 0, in which case it's not visible).
center	Place the object in the center of its container in both the vertical and horizontal axis, not changing its size. When clipOrientation is "horizontal" , clipping occurs on the left and right. When clipOrientation is "vertical" , clipping occurs on the top and bottom.
fill	Grow the horizontal and vertical size of the object if needed so it completely fills its container. No clipping occurs because the drawable fills the horizontal and vertical space (unless the drawable level is 0, in which case it's not visible).
clip_vertical	Additional option that can be set to have the top and/or bottom edges of the child clipped to its container's bounds. The clip is based on the vertical gravity: a top gravity clips the bottom edge, a bottom gravity clips the top edge, and neither clips both edges.
clip_horizontal	Additional option that can be set to have the left and/or right edges of the child clipped to its container's bounds. The clip is based on the horizontal gravity: a left gravity clips the right edge, a right gravity clips the left edge, and neither clips both edges.

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" />

The following layout XML applies the clip drawable to a View:

<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 of clipping in order to progressively reveal the image:

ImageView imageview = (ImageView) findViewById(R.id.image);
ClipDrawable drawable = (ClipDrawable) imageview.getBackground();
drawable.setLevel(drawable.getLevel() + 1000);

Increasing the level reduces the amount of clipping and slowly reveals 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 level is 10,000, the image is not clipped and completely visible.
SEE ALSO:

ClipDrawable

Scale Drawable

A drawable defined in XML that changes the size of another drawable 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 XML namespace, 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 constant values:

Value	Description
top	Put the object at the top of its container, not changing its size.
bottom	Put the object at the bottom of its container, not changing its size.
left	Put the object at the left edge of its container, not changing its size. This is the default.
right	Put the object at the right edge of its container, not changing its size.
center_vertical	Place object in the vertical center of its container, not changing its size.
fill_vertical	Grow the vertical size of the object if needed so it completely fills its container.
center_horizontal	Place object in the horizontal center of its container, not changing its size.
fill_horizontal	Grow the horizontal size of the object if needed so it completely fills its container.
center	Place the object in the center of its container in both the vertical and horizontal axis, not changing its size.
fill	Grow the horizontal and vertical size of the object if needed so it completely fills its container.
clip_vertical	Additional option that can be set to have the top and/or bottom edges of the child clipped to its container's bounds. The clip is based on the vertical gravity: a top gravity clips the bottom edge, a bottom gravity clips the top edge, and neither clips both edges.
clip_horizontal	Additional option that can be set to have the left and/or right edges of the child clipped to its container's bounds. The clip is based on the horizontal gravity: a left gravity clips the right edge, a right gravity clips the left edge, and neither clips both edges.

android:scaleHeight

Percentage. The scale height, expressed as a percentage of the drawable's bound. The value's format is XX%. For instance: 100%, 12.5%, etc.

android:scaleWidth

Percentage. The scale width, expressed as a percentage of the drawable's bound. The value's format is XX%. For instance: 100%, 12.5%, etc.

EXAMPLE:

<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/logo"
android:scaleGravity="center_vertical|center_horizontal"
android:scaleHeight="80%"
android:scaleWidth="80%" />

SEE ALSO:

ScaleDrawable

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

GradientDrawable

.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="float"
android:centerY="float"
android:centerColor="integer"
android:endColor="color"
android:gradientRadius="integer"
android:startColor="color"
android:type=["linear" | "radial" | "sweep"]
android:useLevel=["true" | "false"] />
<padding
android:left="integer"
android:top="integer"
android:right="integer"
android:bottom="integer" />
<size
android:width="integer"
android:height="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 XML namespace, 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 default shape.
"oval"	An oval shape that fits the dimensions of the containing View.
"line"	A horizontal line that spans the width of the containing View. This shape requires the <stroke> element to define the width of the line.
"ring"	A ring shape.

The following attributes are used only when

android: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 radius equals 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 dimension value or dimension
resource.

android:thicknessRatio

Float. The thickness of the ring, expressed as a ratio of the ring's width. For instance, if

android:thicknessRatio="2"

, then the thickness equals the 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" or your shape may not appear.

<corners>

Creates rounded corners for the shape. Applies only when the shape is a rectangle.
attributes:

android:radius

Dimension. The radius for all corners, as a dimension value or dimension
resource. This is overridden for each corner by the following attributes.

android:topLeftRadius

Dimension. The radius for the top-left corner, as a dimension value or dimension
resource.

android:topRightRadius

Dimension. The radius for the top-right corner, as a dimension value or dimension
resource.

android:bottomLeftRadius

Dimension. The radius for the bottom-left corner, as a dimension value or dimension
resource.

android:bottomRightRadius

Dimension. The radius for the bottom-right corner, as a dimension value or dimension
resource.

Note: Every corner must (initially) be provided a corner radius greater than 1, or else no corners are rounded. If you want specific corners to not be rounded, a work-around is to use

android:radius

to set a default
corner radius greater than 1, but then override each and 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 is left 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 the gradient (0 - 1.0).

android:centerY

Float. The relative Y-position for the center of the gradient (0 - 1.0).

android:centerColor

Color. Optional color that comes between the start and end 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. Valid values 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 the position 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 dimension value or dimension
resource.

android:width

Dimension. The width of the shape, as a dimension value or dimension
resource.

Note: The shape scales to the size of 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 the

android:scaleType

"center"

<solid>

A solid color to fill the shape.
attributes:

android:color

Color. The color to apply to the shape, as a hexadecimal value or color
resource.

<stroke>

A stroke line for the shape.
attributes:

android:width

Dimension. The thickness of the line, as a dimension value or dimension
resource.

android:color

Color. The color of the line, as a hexadecimal value or color
resource.

android:dashGap

Dimension. The distance between line dashes, as a dimension value or dimension
resource. Only valid if

android:dashWidth

is set.

android:dashWidth

Dimension. The size of each dash line, as a dimension value or dimension
resource. Only valid if

android:dashGap

is 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 to a View:

Resources res = [code]getResources()

;
Drawable shape = res.

getDrawable

(R.drawable.gradient_box);

TextView tv = (TextView)findViewByID(R.id.textview);
tv.setBackground(shape);[/code]
SEE ALSO:

ShapeDrawable

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Android的资源类型之Drawable

Drawable Resources

See also

Bitmap

Bitmap File

XML Bitmap

Nine-Patch

Nine-Patch File

XML Nine-Patch

Layer List

State List

Level List

Transition Drawable

Inset Drawable

Clip Drawable

Scale Drawable

Shape Drawable