Question

尝试从checkPermissions()返回值后执行setState，但是 async-await 没做。

我在这里找不到任何不正确的地方，您能指出我的错误吗？仅供参考checkPermissions()接受回调函数作为参数。

async componentDidMount() {
    let authorizationStatus = false;
    await PushNotification.checkPermissions(function(permissions) { 
      console.log(permissions); 
      authorizationStatus = permissions.alert
      console.log('Run first')
    });

    console.log('Run after')
    this.setState({
     authorizationStatus,
    });
  }

检查权限代码（Android）

@ReactMethod
    public void checkPermissions(Promise promise) {
      ReactContext reactContext = getReactApplicationContext();
      NotificationManagerCompat managerCompat = NotificationManagerCompat.from(reactContext);
      promise.resolve(managerCompat.areNotificationsEnabled());
    }

解决方案尝试但失败了：仅打印出Run first，没有打印出Run after。

async componentDidMount() {
    let authorizationStatus = false;
    PushNotification.checkPermissions(function(permissions) { 
      console.log(permissions); 
      authorizationStatus = permissions.alert
      console.log('Run first')
      this.setState({
       authorizationStatus,
      },()=>{console.log('Run after')});

    });
  }

Answer 1

您大概正在寻找

async componentDidMount() {
  const permissions = await PushNotification.checkPermissions();
  console.log(permissions); 
  const authorizationStatus = permissions.alert
  console.log('Run first');

  console.log('Run after')
  this.setState({authorizationStatus});
}

您只能await个承诺，不想传递回调。

在“等待”方法完成之前执行的方法

1 个答案: