DART somo la 36: Abstract class kweye Dart

Abstract class ni nini?

Hii ni class yenye abstract method walau moja. Abstract method ni method ambayo ina umetajwa jina ila implementtation yake (yaani code zake kwa ajili ya kuifanyisha kazi) zitakuwepo kwenye subclass. Ufupi wa maneno hii ni method ambayo haina body hivyo yenyewe itatengenishwa kwa semicolon (;) na hutengenezwa kwa kutumia keyword abstract.

Mfano:

abstract class gari{

 //abstract method

 tangazo();

 taarifa();

}

Hapo kuna abstract method 2 ambazo ni tangazo()  na taarifa(). Sasa utaona hizo method zina jina tu lakini hazina body. Sasa body yake tutakwenda kuiona kwenye subclass.

abstract class gari{

 //abstract method

 tangazo();

 taarifa();

}

class toyota extends gari{

 @override

 tangazo() {

   // TODO: implement taarifa

   print("Tunauza gari aina ya toyota");

 }

 @override

 taarifa() {

   // TODO: implement taarifa

   print("Toyota imeuzwa");

 }

}

class bugati extends gari{

 @override

 tangazo() {

   // TODO: implement tangazo

   print("Tunauza gari aina ya Bugati");

 }

 @override

 taarifa() {

   // TODO: implement taarifa

   print("Bugati imeuzwa");

 }

}

class tipa extends gari{

 @override

 tangazo() {

   // TODO: implement taarifa

   print("Tunauza gari aina ya Tipa");

 }

 @override

 taarifa() {

   // TODO: implement taarifa

   print("Tipa limeuzwa");

 }

}

void main(){

 bugati bu = bugati();

 bu.tangazo();

 bu.taarifa();

 print(" ");

 toyota to = toyota();

 to.tangazo();

 to.taarifa();

 print(" ");

 tipa ti = tipa();

 ti.tangazo();

 ti.taarifa();

}

Mambo ya kuzingatia:

1. Huwezi kutengeneza object kwa kutumia abstract class
2. Unaweza kuwa na abstract method na method ambazo sio abstract
3. Abstract method inakuwa na signator moja tu.

Angalia mfano mwingine ambao umechanganya constructor ...