不使用框架搭建投票Dapp

一、开发环境

• Ganache
• Remix
• web3.js

二、编写智能合约

pragma solidity ^0.5.0;

contract Voting {

  mapping (bytes32 => uint8) public votesReceived;

  bytes32[3] public candidateList;

  constructor() public {
    candidateList[0] = 'Rama';
    candidateList[1] = 'Nick';
    candidateList[2] = 'Jose';
  }

  function totalVotesFor(bytes32 candidate) view public returns (uint8) {
    require(validCandidate(candidate));
    return votesReceived[candidate];
  }

  function voteForCandidate(bytes32 candidate) public {
    require(validCandidate(candidate));
    votesReceived[candidate] += 1;
  }

  function validCandidate(bytes32 candidate) view public returns (bool) {
    for(uint i = 0; i < candidateList.length; i++) {
      if (candidateList[i] == candidate) {
        return true;
      }
    }
    return false;
  }
}

三、编译智能合约

四、开启本地节点

五、部署智能合约

• 选择web3 provider
• 点击deploy部署

• 部署成功后，复制下合约地址以及abi

六、web3.js与合约交互

• index.html

  
  


  
A Simple Hello World Voting Application
  

    

      

        

          
Candidate
          
Votes
        
      
      

        

          
Rama
          

        
        

          
Nick
          

        
        

          
Jose
          

        
      
    
  
  
  Vote

• 效果如下