<Button x="0" y="0" w="#screen_width" h="#screen_height">
<Triggers>
<Trigger action="double">
<VariableCommand name="id" expression="ifelse(ge(#id,5),0,#id+1)" persist="true"/>
</Trigger>
</Triggers>
</Button>
<!-- 预设的壁纸 -->
<Image src="No_0.png" x="0" y="0" alignV="bottom" visibility="eq(#id,0)"/>
<Image src="No_1.png" x="0" y="0" alignV="bottom" visibility="eq(#id,1)"/>
<Image src="No_2.png" x="0" y="0" alignV="bottom" visibility="eq(#id,2)"/>
<Image src="No_3.png" x="0" y="0" alignV="bottom" visibility="eq(#id,3)"/>
<Image src="No_4.png" x="0" y="0" alignV="bottom" visibility="eq(#id,4)"/>
<Image src="No_5.png" x="0" y="0" alignV="bottom" visibility="eq(#id,5)"/>
双击切换壁纸,No_1.png,No_2.png是预设壁纸。 action是按钮指令 double是双击 up是抬起 down是按下