Force child classes to implement protocol swift -

-

how can forced child class implement protocol declared in parent class?

i tried this:

protocol myprotocol {     var myvar : string { } }  class parentclass: myprotocol {     var myvar = "parent" }  class childclass: parentclass { }

but child class doesn't force me override myvar.

this possible ?

thank much,

morgan

as far knowledge not possible in swift. if try conforming parent class's protocol, leads error "cannot override stored property". since protocol conformed in parentclass. 

protocol myprotocol {     var myvar : string {  } }  class parentclass: myprotocol {     var myvar = "parent"  }  class childclass: parentclass {     var myvar = "hello"     // throws compilation error, "cannot override stored property" since it's conformed parentclass itself. }

added:

in general words multi-level implementation of interface not possible, in ios words protocol's should implemented @ single level only. since you've inherited parentclass, childclass has scope access parentclass members.

class childclass: parentclass, myprotocol {     func printvalue(){         println("newvalue : \(myvar)")         myvar = "hello"     }  }

hope helps...!


Comments

Post a Comment

Popular posts from this blog

matlab - "Contour not rendered for non-finite ZData" -

-
i'm trying plot frequency characteristic equation using ezplot, matlab gives following warning, "contour not rendered non-finite zdata". have used command plot frequency equations warning , plot display empty , not change axis range well. can please help. appreciated. here's code i'm using. % transfer matrix case-i, thin rotor clear all; clc; ei = 1626; l = 0.15; m = 0.44108; = 2.178*10^-4; i_p = 2.205*10^-5; itr = 0.24; i_pr = 0.479; syms p n; f = [1 l*1i l^2/(2*ei)*1i l^3/(6*ei); 0 1 l/ei -l^2/(2*ei)*1i; 0 0 1 -l*1i; 0 0 0 l]; p = [ 1 0 0 0; 0 1 0 0; 0 -it*p^2+i_p*n*p 1 0; -m*p^2 0 0 1]; p_r = [1 0 0 0; 0 1 0 0; 0 -itr*p^2+i_pr*n*p 1 0; -m*p^2 0 0 1]; = f*p*f*p*f*p*f; b = p_r*f*p*f*p*f; r = a(1,2)/a(1,4); a12_p = 0; a22_p = a(2,2)-r*a(2,4); a32_p = a(3,2)-r*a(3,4); a42_p = a(4,2)-r*a(4,4); ap(2,2) = a22_p; ap(3,2) = a32_p; ap(4,2) = a42_p; ap(4,4) = 1; c = b*ap; m = [c(3,2) c(3,4); c(4,2) c(4,...
Read more

delphi - Indy UDP Read Contents of Adata -

-
i using indy udp server read string of data. however, not know how work adata parameter. can around converting binary using bytetobin function below , convert hex using bintohex1 . feel stupid , works slow. know how can directly results without 2 conversions? thanks!! here codes: procedure tform1.idudpserver1udpread(athread: tidudplistenerthread; const adata: tidbytes; abinding: tidsockethandle); var buf: tidbytes; buffer: string; data_received: string; begin if bytestostring(adata) <> 'hello' begin buffer := hextostring('00'); setlength(buf, length(buffer)); copytidstring(buffer, buf, 0); abinding.sendto(abinding.peerip, abinding.peerport, buf); data_received := bintohex1(bytetobin(adata[1]) + bytetobin(adata[2]) + bytetobin(adata[3]) + bytetobin(adata[4]) + bytetobin(adata[5]) + bytetobin(adata[6]) + bytetobin(adata[7]) + bytetobin(adata[8]) + bytetobin(adata[9]) + bytetobin(adata[10]) + bytetobin(adata[11...
Read more

javascript - Any ideas when Firefox is likely to implement lengthAdjust and textLength? -

-
any ideas when firefox implement lengthadjust andtextlength?..... working svg application. lengthadjust , textlength working fine in chrome not working in fire fox . <svg viewbox = "0 0 500 300" version = "1.1"> <defs> <path id="s3" d="m 10,90 q 100,15 200,70" /> </defs> <g> <text font-size = "20"> <textpath xlink:href="#s3" textlength="205"> short text</textpath> </text> <use xlink:href="#s3" fill="none" stroke="black" stroke-width="1"/> </g> </svg> this implemented in firefox text elements (not textpath or tspan) in case that's ok though can move attribute text element. <svg viewbox = "0 0 500 300" version = "1.1"> <defs> ...
Read more