反应 setState 不更新状态 [英] React setState not updating state

问题描述

所以我有这个:

let total = newDealersDeckTotal.reduce(function(a, b) {
  return a + b;
},
0);

console.log(total, 'tittal'); //outputs correct total
setTimeout(() => {
  this.setState({ dealersOverallTotal: total });
}, 10);

console.log(this.state.dealersOverallTotal, 'dealersOverallTotal1'); //outputs incorrect total

newDealersDeckTotal 只是一个数字数组 [1, 5, 9] 例如但是 this.state.dealersOverallTotal 没有给出正确的总数，但 total 有吗?我什至设置了超时延迟，看看这是否解决了问题.任何明显的还是我应该发布更多代码?

newDealersDeckTotal is just an array of numbers [1, 5, 9] e.g. however this.state.dealersOverallTotal does not give the correct total but total does? I even put in a timeout delay to see if this solved the problem. any obvious or should I post more code?

推荐答案

setState() 通常是异步的，这意味着你在 console.log 时的状态，还没更新.尝试将日志放入 setState() 方法的回调中.状态改变完成后执行:

setState() is usually asynchronous, which means that at the time you console.log the state, it's not updated yet. Try putting the log in the callback of the setState() method. It is executed after the state change is complete:

this.setState({ dealersOverallTotal: total }, () => {
  console.log(this.state.dealersOverallTotal, 'dealersOverallTotal1');
}); 

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