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Android屏幕尺寸与度量单位(px,dp,sp)简介

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1.各度量单位的含义

  • px:pixels(像素)。显示器是由一个一个的像素点组成的,例如在通用显示器中,每英寸包括72个像素点;
  • dp:device independent pixels(设备独立像素),不同的设备有不同的显示效果,这个和设备硬件有关;Android中,使用dp可以对目标进行自动缩放,比较方便兼容不同尺寸的设备;详见下面介绍;
  • dip:和dp是一样的,Android的早期版本使用了dip这个称呼,后来改成了dp;
  • pt:point,这个是一个标准的长度单位,注意与px区分,1pt=1/72英寸,主要用于印刷行业
  • sp:scaled pixels,主要用于字体的大小显示,个人理解,sp其实和dp差不多,唯一的区别在于sp可以随系统字体进行放大缩小,,当在设置中选中大字体模式后,使用sp标注的字体大小会自动缩放;
  • in(英寸):长度单位
  • mm(毫米):长度单位
  • PPI:密度单位,表示每英寸包括多少个像素点,如显示器一般为72ppi

2.像素密度

Android设备主要包括以下几种屏幕:

屏幕 宽度 高度 尺寸 屏幕密度
QVGA 240 320 2.6-3.0 LOW
WQVGA 240 400 3.2-3.5 LOW
FWQVGA 240 432 3.5-3.8 LOW
HVGA 320 480 3.0-3.5 MEDIUM
WVGA 480 800 3.3-4.0 high
FWVGA 480 854 3.5-4.0 HIGH
wvga 480 800 4.8-5.5 MEDIUM
FWVGA 480 854 5.0-5.8 MEDIUM
VGA 480 640 2.8 286ppi

备注:目前Android默认的low=120;medium=160;high=240
设备信息有很多,具体的可以参考下面链接:
http://www.xyaz.cn/thread-71-1-1.html

3.px与dp的转换

转换公式为:
px=dp*density/160。denisty表示屏幕密度,即当density=160时,1dp = 1px = 1sp;

转载请注明原文地址:
http://www.cnblogs.com/yanyojun/p/6250383.html

Android屏幕尺寸与度量单位(px,dp,sp)简介