文章转载自：https://blog.csdn.net/student9128/article/details/53932470

众所周知，在Android开发中dp和px,sp和px之间的转换时必不可少的，下面将转换的代码记录下来：

public class DisplayUtils {

    /**
     * convert px to its equivalent dp
     * <p>
     * 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
     * <p>
     * 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
     * <p>
     * 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
     * <p>
     * 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);
    }

}

同时系统也提供了TypedValue类帮助我们转换

/**
 * 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());
}