Android Drawable Resource学习（十）、ScaleDrawable



另一个drawable资源，基于当前的level，进行尺寸变换的drawable。

文件位置：

res/drawable/filename.xml
文件名即资源名

编译数据类型：

指向 ScaleDrawable的指针。

资源引用：

In Java: R.drawable.filename
In XML: @[package:]drawable/filename

语法：

<span class="pun"><?</span><span class="pln">xml version</span><span class="pun">=</span><span class="str">"1.0"</span><span class="pln"> encoding</span><span class="pun">=</span><span class="str">"utf-8"</span><span class="pun">?></span><span class="pln"></span><span class="tag"><</span><a><span class="tag">scale</span></a><span class="pln">    </span><span class="atn">xmlns:android</span><span class="pun">=</span><span class="atv">"http://schemas.android.com/apk/res/android"</span><span class="pln">    </span><span class="atn">android:drawable</span><span class="pun">=</span><span class="atv">"@drawable/</span><em><span class="atv">drawable_resource</span></em><span class="atv">"</span><span class="pln">    </span><span class="atn">android:scaleGravity</span><span class="pun">=</span><span class="atv">["top"</span><span class="pln"> | </span><span class="atv">"bottom"</span><span class="pln"> | </span><span class="atv">"left"</span><span class="pln"> | </span><span class="atv">"right"</span><span class="pln"> | </span><span class="atv">"center_vertical"</span><span class="pln"> |                          </span><span class="atv">"fill_vertical"</span><span class="pln"> | </span><span class="atv">"center_horizontal"</span><span class="pln"> | </span><span class="atv">"fill_horizontal"</span><span class="pln"> |                          </span><span class="atv">"center"</span><span class="pln"> | </span><span class="atv">"fill"</span><span class="pln"> | </span><span class="atv">"clip_vertical"</span><span class="pln"> | </span><span class="atv">"clip_horizontal"</span><span class="pln">]    </span><span class="atn">android:scaleHeight</span><span class="pun">=</span><span class="atv">"</span><em><span class="atv">percentage</span></em><span class="atv">"</span><span class="pln">    </span><span class="atn">android:scaleWidth</span><span class="pun">=</span><span class="atv">"</span><em><span class="atv">percentage</span></em><span class="atv">"</span><span class="pln"> </span><span class="tag">/></span>

元素：

<scale>

定义一个ScaleDrawable，必须作为根元素。

属性：

xmlns:android

String类型。 必须的。定义XML文件的命名空间。必须是 "http://schemas.android.com/apk/res/android".

android:drawable

Drawable 资源。必须的。引用一个drawable资源。

android:scaleGravity

关键字。指定缩放后的gravity的位置。

必须是下面的一个或多个值（多个值之间用”|“分隔），下面的值和描述和上一篇的ClipDrawable一样。

值描述topPut the object at the top of its container, not changing its size.bottomPut the object at the bottom of its container, not changing its size.leftPut the object at the left edge of its container, not changing its size. This is thedefault.rightPut the object at the right edge of its container, not changing its size.center_verticalPlace object in the vertical center of its container, not changing its size.fill_verticalGrow the vertical size of the object if needed so it completely fills its container.center_horizontalPlace object in the horizontal center of its container, not changing its size.fill_horizontalGrow the horizontal size of the object if needed so it completely fills its container.centerPlace the object in the center of its container in both the vertical and horizontal axis, notchanging its size.fillGrow the horizontal and vertical size of the object if needed so it completely fills itscontainer.clip_verticalAdditional option that can be set to have the top and/or bottom edges of the child clipped toits container's bounds. The clip is based on the vertical gravity: a top gravity clips thebottom edge, a bottom gravity clips the top edge, and neither clips both edges.clip_horizontalAdditional option that can be set to have the left and/or right edges of the child clipped toits container's bounds. The clip is based on the horizontal gravity: a left gravity clipsthe right edge, a right gravity clips the left edge, and neither clips both edges.

android:scaleHeight

Percentage（百分比）缩放的高度，以百分比的方式表示drawable的缩放。形式例如：100%，12.5%。

android:scaleWidth

Percentage（百分比）缩放的宽度，以百分比的方式表示drawable的缩放。形式例如：100%，12.5%。

示例：

<span class="pun"><?</span><span class="pln">xml version</span><span class="pun">=</span><span class="str">"1.0"</span><span class="pln"> encoding</span><span class="pun">=</span><span class="str">"utf-8"</span><span class="pun">?></span><span class="pln"></span><span class="tag"><scale</span><span class="pln"> </span><span class="atn">xmlns:android</span><span class="pun">=</span><span class="atv">"http://schemas.android.com/apk/res/android"</span><span class="pln">    </span><span class="atn">android:drawable</span><span class="pun">=</span><span class="atv">"@drawable/logo"</span><span class="pln">    </span><span class="atn">android:scaleGravity</span><span class="pun">=</span><span class="atv">"center_vertical|center_horizontal"</span><span class="pln">    </span><span class="atn">android:scaleHeight</span><span class="pun">=</span><span class="atv">"80%"</span><span class="pln"> //表示从高度80% 开始缩放，80%为图片高度最小值。level 0不可见。    </span><span class="atn">android:scaleWidth</span><span class="pun">=</span><span class="atv">"80%"</span><span class="tag">/></span><span class="pln"> </span><span class="pln">//表示从宽度80% 开始缩放，80%为图片宽度最小值。level 0不可见。</span>

参考：

• ScaleDrawable

示例：

在scale.xml中：

[java] view plaincopyprint?

1. <?xml version="1.0" encoding="utf-8"?>  
2. <scale xmlns:android="http://schemas.android.com/apk/res/android"  
3.     android:scaleWidth="50%"  
4.     android:scaleHeight="50%"  
5.     android:drawable="@drawable/image1"   
6.     android:scaleGravity="center_vertical|center_horizontal"  
7.     >  
8. </scale>  

<?xml version="1.0" encoding="utf-8"?><scale xmlns:android="http://schemas.android.com/apk/res/android"    android:scaleWidth="50%"    android:scaleHeight="50%"    android:drawable="@drawable/image1"     android:scaleGravity="center_vertical|center_horizontal"    ></scale>

在layout中使用：

[java] view plaincopyprint?

1. <ImageView   
2.     android:id="@+id/imgView"  
3.     android:src="@drawable/scale"  
4.     android:layout_width="wrap_content"  
5.     android:layout_height="wrap_content"/>  

    <ImageView         android:id="@+id/imgView"        android:src="@drawable/scale"        android:layout_width="wrap_content"        android:layout_height="wrap_content"/>

在代码中设置level：

[java] view plaincopyprint?

1.  ImageView imageView=(ImageView)findViewById(R.id.imgView);  
2.         ScaleDrawable scaleDrawable=(ScaleDrawable)imageView.getDrawable();  
3.         scaleDrawable.setLevel(1);  //level 1的时候就是50%  
4. <pre class="java" name="code">        //scaleDrawable.setLevel(0); //level 0不可见</pre><br>  
5. <pre></pre>  
6. <p></p>  
7. <pre></pre>  
8. <br>  
9. <img alt="" src="http://img.my.csdn.net/uploads/201212/03/1354516551_4610.jpg"><br>  
10. <p></p>  
11. <p><br>  
12. </p>  
13. <pre></pre>