Mastering Angular Material Tooltips: Show and Hide with Grace
Angular Material's tooltips provide an elegant way to display helpful information to users. But what if you need to conditionally show or hide them based on factors like screen size? This is a common challenge, and one that can be solved with a bit of cleverness.
The Problem:
As the user pointed out on Stack Overflow link to original question, the ngIf directive doesn't play nicely with Angular Material's <md-tooltip> component. This makes hiding tooltips dynamically tricky.
The Solution:
There are several approaches you can take to achieve this behavior. Here's a breakdown of the most effective solutions:
1. Using ng-container and *ngIf:
The key to this solution is wrapping the <md-tooltip> component within an ng-container and using the *ngIf directive to control its visibility.
<ng-container *ngIf="isTooltipVisible">
<md-tooltip md-delay="500">
Tooltip content goes here.
</md-tooltip>
</ng-container>
In your component's TypeScript file, you'd define the isTooltipVisible variable and set it based on your desired conditions.
import { Component } from '@angular/core';
@Component({
selector: 'app-my-component',
template: `
<button mat-raised-button>
Hover Me
<ng-container *ngIf="isTooltipVisible">
<md-tooltip md-delay="500">
Tooltip content goes here.
</md-tooltip>
</ng-container>
</button>
`,
})
export class MyComponent {
isTooltipVisible = true;
// ... other component logic
}
This approach allows you to control the tooltip's visibility dynamically based on screen size, user interaction, or any other condition you choose.
2. Implementing a Custom Directive:
For more complex scenarios, you might want to create a custom directive to handle the logic. This directive could listen to events, calculate screen size, and conditionally show or hide the tooltip.
Here's a simplified example:
import { Directive, ElementRef, HostListener, Input, OnInit } from '@angular/core';
@Directive({
selector: '[appShowHideTooltip]'
})
export class ShowHideTooltipDirective implements OnInit {
@Input() appShowHideTooltip: boolean;
constructor(private elementRef: ElementRef) {}
ngOnInit() {
this.updateTooltipVisibility();
}
@HostListener('window:resize', ['$event'])
onResize(event: Event) {
this.updateTooltipVisibility();
}
updateTooltipVisibility() {
if (this.appShowHideTooltip) {
this.elementRef.nativeElement.style.display = 'block';
} else {
this.elementRef.nativeElement.style.display = 'none';
}
}
}
This directive listens for window resize events and uses the appShowHideTooltip input to control the tooltip's visibility.
Additional Considerations:
- Screen Size Detection: You can use libraries like
@angular/cdk/platformor create your own logic to determine when the screen size changes. - Performance: Be mindful of the performance impact of constantly recalculating tooltip visibility. Consider using debouncing or throttling techniques for resize events.
Conclusion:
Mastering conditional tooltips in Angular Material empowers you to create more user-friendly and engaging experiences. By leveraging ng-container, *ngIf, and custom directives, you can ensure your tooltips appear only when they are most helpful, leading to a better user experience.
