import android.content.Context;  
    import android.util.TypedValue;  
      
    //常用单位转换的辅助类  
    public class DensityUtils  
    {  
        private DensityUtils()  
        {  
            /* cannot be instantiated */  
            throw new UnsupportedOperationException("cannot be instantiated");  
        }  
      
        /** 
         * dp转px 
         *  
         * @param context 
         * @param val 
         * @return 
         */  
        public static int dp2px(Context context, float dpVal)  
        {  
            return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,  
                    dpVal, context.getResources().getDisplayMetrics());  
        }  
      
        /** 
         * sp转px 
         *  
         * @param context 
         * @param val 
         * @return 
         */  
        public static int sp2px(Context context, float spVal)  
        {  
            return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,  
                    spVal, context.getResources().getDisplayMetrics());  
        }  
      
        /** 
         * px转dp 
         *  
         * @param context 
         * @param pxVal 
         * @return 
         */  
        public static float px2dp(Context context, float pxVal)  
        {  
            final float scale = context.getResources().getDisplayMetrics().density;  
            return (pxVal / scale);  
        }  
      
        /** 
         * px转sp 
         *  
         * @param fontScale 
         * @param pxVal 
         * @return 
         */  
        public static float px2sp(Context context, float pxVal)  
        {  
            return (pxVal / context.getResources().getDisplayMetrics().scaledDensity);  
        }  
      
    }