Android dp，px，sp之間的轉換

官方方法

float dp = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 20f, getResources().getDisplayMetrics());      

該方法源碼:

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;
}      

其他方法

public class SizeUtil {
    /**
     * DP轉PX
     * @param context
     * @param dpValue
     * @return
     */
    public static int dip2px(Context context, float dpValue) {
        float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    /**
     * sp轉px
     * @param spValue
     * @return
     */
    public static int sp2px(Context context, float spValue) {
        final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
        return (int) (spValue * fontScale + 0.5f);
    }

    /**
     * PX轉DP
     * @param context
     * @param pxValue
     * @return
     */
    public static int px2dip(Context context, float pxValue) {
        float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

    /**
     * px轉sp值
     * @param pxValue
     * @return
     */

    public static int px2sp(Context context, float pxValue) {
        final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
        return (int) (pxValue / fontScale + 0.5f);
    }
}