android中px和dp,px和sp之间的转换方法

public class DisplayUtils {  /**   * convert px to its equivalent dp   * 将px转换为与之相等的dp   */  public static int px2dp(Context context, float pxValue) {    final float scale = context.getResources().getDisplayMetrics().density;    return (int) (pxValue / scale + 0.5f);  }  /**   * convert dp to its equivalent px   * 将dp转换为与之相等的px   */  public static int dp2px(Context context, float dipValue) {    final float scale = context.getResources().getDisplayMetrics().density;    return (int) (dipValue * scale + 0.5f);  }  /**   * convert px to its equivalent sp    * 将px转换为sp   */  public static int px2sp(Context context, float pxValue) {    final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;    return (int) (pxValue / fontScale + 0.5f);  }  /**   * convert sp to its equivalent px   * 将sp转换为px   */  public static int sp2px(Context context, float spValue) {    final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;    return (int) (spValue * fontScale + 0.5f);  }}

/*** convert dp to its equivalent px*/protected int dp2px(int dp){    return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,getResources().getDisplayMetrics());}/*** convert sp to its equivalent px*/protected int sp2px(int sp){    return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, sp,getResources().getDisplayMetrics());}public class TypedValue {  ...  /** {@link #TYPE_DIMENSION} complex unit: Value is raw pixels. */  public static final int COMPLEX_UNIT_PX = 0;  /** {@link #TYPE_DIMENSION} complex unit: Value is Device Independent   * Pixels. */  public static final int COMPLEX_UNIT_DIP = 1;  /** {@link #TYPE_DIMENSION} complex unit: Value is a scaled pixel. */  public static final int COMPLEX_UNIT_SP = 2;  /** {@link #TYPE_DIMENSION} complex unit: Value is in points. */  public static final int COMPLEX_UNIT_PT = 3;  /** {@link #TYPE_DIMENSION} complex unit: Value is in inches. */  public static final int COMPLEX_UNIT_IN = 4;  /** {@link #TYPE_DIMENSION} 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 <var>unit</var> and <var>value</var>   * are as in {@link #TYPE_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:      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;  }  ...}