android 字体px转sp,Android的计量单位px/dip/dp/sp/pt/in/mm，及相互转换

px   ：原始像素点(raw Pixel)。 dip  ：设备独立点(Device Independent Pixel)，会根据屏幕的密度(density)进行缩放。dp   ：同dip，是其简写。 sp   ：缩放像素点(Scaled Pixel)，会根据用户选择的字体大小(scaledDensity)进行缩放。

pt    ：英磅(Point)，英寸的1/72。

in    ：英寸(Inch)。

mm ：毫米(Millimeter)

建议：文字尺寸使用sp，其他尺寸使用dp。

//android.util.TypedValue

/**  complex unit: Value is raw pixels. */

public static final int COMPLEX_UNIT_PX = 0;

/**  complex unit: Value is Device Independent Pixels. */

public static final int COMPLEX_UNIT_DIP = 1;

/**  complex unit: Value is a scaled pixel. */

public static final int COMPLEX_UNIT_SP = 2;

/**  complex unit: Value is in points. */

public static final int COMPLEX_UNIT_PT = 3;

/**  complex unit: Value is in inches. */

public static final int COMPLEX_UNIT_IN = 4;

/**  complex unit: Value is in millimeters. */

public static final int COMPLEX_UNIT_MM = 5;

/**

* Converts an unpacked complex data value holding a dimension to its final

* floating point value. The two parameters unit and value are as in dimension.

*

* @param unit The unit to convert from.

* @param value The value to apply the unit to.

* @param metrics Current display metrics to use in the conversion --

* supplies display density and scaling information.

*

* @return The complex floating point value multiplied by the appropriate

* metrics depending on its unit.

*/

public static float applyDimension(int unit, float value,

DisplayMetrics metrics)

{

switch (unit) {

case COMPLEX_UNIT_PX: //原始像素点

return value;

case COMPLEX_UNIT_DIP: //设备独立点

return value * metrics.density;

case COMPLEX_UNIT_SP: //缩放像素点

return value * metrics.scaledDensity;

case COMPLEX_UNIT_PT: //英磅

return value * metrics.xdpi * (1.0f/72);

case COMPLEX_UNIT_IN: //英寸

return value * metrics.xdpi;

case COMPLEX_UNIT_MM: //毫米

return value * metrics.xdpi * (1.0f/25.4f);

}

return 0;

}