constructor(props) {
super(props);
console.log("props");
this.state = {
userId : "12345",
};
}
componentDidMount() {
console.log("componentDidMount");
Actions.getProductDetails({userId:"123456"});
Actions.getProductDetails.completed.listen(this.gotProductDetails.bind(this));
Actions.cancelOrder.completed.listen(this.cancelOrderCompleted.bind(this));
}
gotProductDetails(data) {
console.log("gotProductDetails");
}
goBack(data) {
console.log("justgoback");
this.props.back();
}
cancelProduct() {
console.log("SDsadsadsad");
Actions.cancelOrder({
orderId:this.state.order.id,
canelMsg:this.state.selectedReason,
userId:this.state.userId
});
}
cancelOrderCompleted(data) {
console.log("cancelOrderCompleted");
this.goBack();
}
My issue is some functions are mounting twice whenever I change the route and revisit this route again I would show you console.log here
这是我第一次来到这条路线:
props
cancelOrder.js:190 componentDidMount
cancelOrder.js:197 gotProductDetails
现在我将进行 cancelProduct 调用,日志将是
SDsadsadsad
cancelOrder.js:221 cancelOrderCompleted
cancelOrder.js:210 justgoback
这是第二次,即我将从这条路线返回并重新访问:
props
cancelOrder.js:190 componentDidMount
cancelOrder.js:197 gotProductDetails
Warning: setState(...): Can only update a mounted or mounting component. This usually means you called setState() on an unmounted component. This is a no-op. Please check the code for the cancelOrder component.
cancelOrder.js:197 gotProductDetails
现在我将进行 cancelProduct 调用,日志将是
SDsadsadsad
cancelOrder.js:221 cancelOrderCompleted
cancelOrder.js:210 justgoback
cancelOrder.js:221 cancelOrderCompleted
cancelOrder.js:210 justgoback
在上面的日志中,您可以看到第二次行号 197 221 210 执行了两次并出现错误
我无法解决
我正在为 route 使用 React navigator
我也检查了发布版本,但它有与在一个 Github 问题中告诉的相同错误,但现在无法找到。
最佳答案
每次运行此行时
Actions.cancelOrder.completed.listen(this.cancelOrderCompleted.bind(this));
listen
方法每次运行时都会获取一个新的函数实例,因此,如果此页面在应用的生命周期中安装了两次,cancelOrderCompleted
将运行两次,并且其中之一它们可能位于未安装的组件中,这很糟糕。
一般来说,我建议您的 getProductDetails
返回一个 Promise
。如果您不想这样做,请确保在卸载组件时删除监听器。
请注意,cancelOrderCompleted.bind(this)
会创建一个新的委托(delegate)实例,在停止监听器时您无法重新创建该实例。除非您将其保存在数据成员中。
编辑:
代码示例 -
constructor(props) {
super(props);
console.log("props");
this.state={
userId : "12345",
}
this.getProductDetailsBound = this.gotProductDetails.bind(this);
this.cancelOrderCompletedBound = this.cancelOrderCompleted.bind(this);
}
componentDidMount() {
console.log("componentDidMount")
// Listen before you call getProductDetails, not after
Actions.getProductDetails.completed.listen(this.getProductDetailsBound);
Actions.cancelOrder.completed.listen(this.cancelOrderCompletedBound);
Actions.getProductDetails({userId:"123456"});
}
componentWillUnmount() {
Actions.getProductDetails.completed.stopListening(this.getProductDetailsBound);
Actions.cancelOrder.completed.stopListening(this.cancelOrderCompletedBound);
}
关于javascript - React-native componentDidMount 从服务器获取,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43062755/