android屏幕 单位转换

http://www.cnblogs.com/zhouchanwen/archive/2012/10/20/2731984.html

在android内部会使用TypedValue.applyDimension函数将所有单位换算成px。

public static float applyDimension(int unit, float value,                                    DisplayMetrics metrics) {     switch (unit) {     case COMPLEX_UNIT_PX:         return value;     case COMPLEX_UNIT_DIP:         return value * metrics.density;     case COMPLEX_UNIT_SP:         return value * metrics.scaledDensity;     case COMPLEX_UNIT_PT:         return value * metrics.xdpi * (1.0f/72);     case COMPLEX_UNIT_IN:         return value * metrics.xdpi;     case COMPLEX_UNIT_MM:         return value * metrics.xdpi * (1.0f/25.4f);     }     return 0; }

 

public static float applyDimension(int unit, float value, DisplayMetrics metrics)

Since: API Level 1

Converts an unpacked complex data value holding a dimension to its final floating point value. The two parametersunit and value are as in TYPE_DIMENSION.

Parameters

unitThe unit to convert from.valueThe value to apply the unit to.metricsCurrent display metrics to use in the conversion -- supplies display density and scaling information.

Returns

• The complex floating point value multiplied by the appropriate metrics depending on its unit.

 

/**  * Android大小单位转换工具类  *   * @author wader  *   */ public class DisplayUtil {  /**   * 将px值转换为dip或dp值，保证尺寸大小不变   *    * @param pxValue   * @param scale（DisplayMetrics类中属性density）   * @return   */  public static int px2dip(float pxValue, float scale) {   return (int) (pxValue / scale + 0.5f);  }   /**   * 将dip或dp值转换为px值，保证尺寸大小不变   *    * @param dipValue   * @param scale（DisplayMetrics类中属性density）   * @return   */  public static int dip2px(float dipValue, float scale) {   return (int) (dipValue * scale + 0.5f);  }   /**   * 将px值转换为sp值，保证文字大小不变   *    * @param pxValue   * @param fontScale（DisplayMetrics类中属性scaledDensity）   * @return   */  public static int px2sp(float pxValue, float fontScale) {   return (int) (pxValue / fontScale + 0.5f);  }   /**   * 将sp值转换为px值，保证文字大小不变   *    * @param spValue   * @param fontScale（DisplayMetrics类中属性scaledDensity）   * @return   */  public static int sp2px(float spValue, float fontScale) {   return (int) (spValue * fontScale + 0.5f);  } }