在每个子组件中，添加输出:

In each of your child components, add an output:

@Output
initialized = new EventEmitter<boolean>();

并在您确定组件已初始化(或如您的问题所述已加载)时发出一个事件，因此可以显示下一个事件:

and emit an event when you decide that the component is initialized (or loaded, as your question says), and that the next one can thus be displayed:

ngOnInit() {
  ...
  this.initialized.emit(true);
}

在父组件中，有一个计数器:

In the parent component, have a counter:

counter = 0;

每次初始化组件时都增加计数器，直到计数器允许显示组件时才显示组件:

Increment the counter every time a component is initialized, and don't display a component until the counter is allowing it to be displayed:

<child1-component (initialized)="counter++"></child1-component>
<child2-component (initialized)="counter++" *ngIf="counter > 0"></child2-component>
<child3-component (initialized)="counter++" *ngIf="counter > 1"></child3-component>
<child4-component (initialized)="counter++" *ngIf="counter > 2"></child4-component>