说明：  引用 Android上dip、dp、px、sp等单位说明 dip: device independent pixels(设备独立像素). 不同设备有不同的显示效果,这个和设备硬件有关，一般我们为了支持WVGA、HVGA和QVGA 推荐使用这个，不依赖像素。 px: pixels(像素). 不同设备显示效果相同，一般我们HVGA代表320x480像素，这个用的比较多。 pt: point，是一个标准的长度单位，1pt＝1/72英寸，用于印刷业，非常简单易用； sp: scaled pixels(放大像素). 主要用于字体显示best for textsize。
(Quoted on Android dip, dp, px, sp, and other units instructions Dip: device independent pixels (equipment independent pixels. Different equipment have different display effect, this and equipment hardware, generally we in order to support WVGA, HVGA and recommended the QVGA, do not depend on the pixels. Px: pixels (pixel). Different equipment to display the same, generally we HVGA represents 320 x480 pixels, the use of more. Pt: point, is a standard length, the 1 pt = 1/72 ", used for printing, very easy to use Sp: scaled pixels (enlarge pixels). Mainly used for best for textsize font. )