Oraclize 隨機數只工作一次，然後不觸發事件，需要大量的 ETH

所以我使用下面的程式碼

contract Damble is usingOraclize{

function Damble() {
   getRandomNumber();

}
   function __callback(bytes32 _queryId, string _result, bytes _proof) { 
   if (msg.sender != oraclize_cbAddress()) throw;

   if (oraclize_randomDS_proofVerify__returnCode(_queryId, _result, _proof) != 0) {
       // the proof verification has failed, do we need to take any action here? (depends on the use case)
   } else {
       // the proof verification has passed
       // now that we know that the random number was safely generated, let's use it..

       newRandomNumber_bytes(bytes(_result)); // this is the resulting random number (bytes)

       // for simplicity of use, let's also convert the random bytes to uint if we need
       uint maxRange = 10000000; // this is the highest uint we want to get. It should never be greater than 2^(8*N), where N is the number of random bytes we had asked the datasource to return
       uint randomNumber = uint(sha3(_result)) % maxRange; // this is an efficient way to get the uint out in the [0, maxRange] range

       newRandomNumber_uint(randomNumber); // this is the resulting random number (uint)
   }
}

function getRandomNumber() payable{ 
   oraclize_setProof(proofType_Ledger); // sets the Ledger authenticity proof
   uint N = 4; // number of random bytes we want the datasource to return
   uint delay = 0; // number of seconds to wait before the execution takes place
   uint callbackGas = 200000; // amount of gas we want Oraclize to set for the callback function
   bytes32 queryId = oraclize_newRandomDSQuery(delay, N, callbackGas);
}

第一次getRandomNumber()從建構子呼叫一切正常。當我想用某個值手動呼叫 getRandomNumber（以支付 Oraclize 值）時，我需要投入價值超過 5 美元的 eth，否則交易會失敗，但會稀釋我的合約乙太幣餘額。除此之外，當我getRandomNumber()在從建構子呼叫的建構子之後呼叫時，即使事務來自 Oraclize 地址，也不會觸發任何事件。

編輯：這是我的契約的連結：https ://ropsten.etherscan.io/address/0x92f0dbf8b218e03f288da42c0f6d4df7de40c3f2

問題似乎已經解決了，可能是通過在契約本身內取得一些平衡。

引用自：https://ethereum.stackexchange.com/questions/50101