Drawable资源之ClipDrawable资源

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"?>
<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:

<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 clipOrientationis "horizontal", clipping occurs on the left and right. WhenclipOrientation 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.getDrawable();
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.