以LinearLayout为例，它提供的background属性将会将背景图片拉伸，相当难看。事实上我们只需做少量的修改就可以实现web编程中css背景图片的效果。来试试吧。
Bitmap介绍
A Drawable that wraps a bitmap and can be tiled, stretched, or aligned. You can create a BitmapDrawable from a file path, an input stream, through XML inflation, or from a Bitmap object.
属性 android:tileMode
Defines the tile mode. When the tile mode is enabled, the bitmap is repeated. Gravity is ignored when the tile mode is enabled.
Constant Value Description
disabled -1 Do not tile the bitmap. This is the default value.
clamp 0 Replicates the edge color.
repeat 1 Repeats the bitmap in both direction.
mirror 2 Repeats the shader s image horizontally and vertically, alternating mirror images so that adjacent images always seam.
创建重复的背景图片
在drawable目录下创建一个repeat_bg.xml:
<?xml version="1.0" encoding="utf-8"?>
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:src="@drawable/bg" ;
android:tileMode="repeat" />
然后在布局的xml文件中可以这样引用:
<LinearLayout android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/repeat_bg">
;</LinearLayout>
创建横向重复的背景图repeat-x
创建纵向重复的背景图repeat-y
