Auto hide show expand collapse icon in Angular Treeview component
13 Feb 20237 minutes to read
You can display the expand icon by hovering the mouse over TreeView and hide the expand icon by leaving the mouse from TreeView. Refer to the following code sample to hide/show the expand/collapse icon automatically using the mouse.
import { Component, Inject, ViewChild } from '@angular/core';
import { TreeViewComponent} from '@syncfusion/ej2-angular-navigations';
/**
* TreeView Auto hide/show expand/collapse icons
*/
@Component({
selector: 'app-container',
template: `<div id='treeparent'><ejs-treeview id='treeElement' #treevalidate [fields]='field' (created)='onCreate($event)'></ejs-treeview></div>`
})
export class AppComponent {
// Data source for TreeView component
public countries: Object[] = [
{ id: 1, name: 'India', hasChild: true },
{ id: 2, pid: 1, name: 'Assam' },
{ id: 3, pid: 1, name: 'Bihar' },
{ id: 4, pid: 1, name: 'Tamil Nadu' },
{ id: 6, pid: 1, name: 'Punjab' },
{ id: 7, name: 'Brazil', hasChild: true },
{ id: 8, pid: 7, name: 'ParanĂ¡' },
{ id: 9, pid: 7, name: 'CearĂ¡' },
{ id: 10, pid: 7, name: 'Acre' },
{ id: 11, name: 'France', hasChild: true },
{ id: 12, pid: 11, name: 'Pays de la Loire' },
{ id: 13, pid: 11, name: 'Aquitaine' },
{ id: 14, pid: 11, name: 'Brittany' },
{ id: 15, pid: 11, name: 'Lorraine' },
{ id: 16, name: 'Australia', hasChild: true },
{ id: 17, pid: 16, name: 'New South Wales' },
{ id: 18, pid: 16, name: 'Victoria' },
{ id: 19, pid: 16, name: 'South Australia' },
{ id: 20, pid: 16, name: 'Western Australia' },
{ id: 21, name: 'China', hasChild: true },
{ id: 22, pid: 21, name: 'Guangzhou' },
{ id: 23, pid: 21, name: 'Shanghai' },
{ id: 24, pid: 21, name: 'Beijing' },
{ id: 25, pid: 21, name: 'Shantou' }
];
public field:Object ={ dataSource: this.countries, id: 'id', text: 'name', parentID: 'pid', hasChildren: 'hasChild' };
@ViewChild ('treevalidate') tree: TreeViewComponent;
public onCreate(): void {
let collapse: NodeListOf<Element> = this.tree.element.querySelectorAll('.e-icons.e-icon-collapsible');
let expand: NodeListOf<Element> = this.tree.element.querySelectorAll('.e-icons.e-icon-expandable');
this.hideIcon(expand, collapse);
this.tree.element.addEventListener('mouseenter', (event:any) => {
this.showIcon(expand, collapse);
});
this.tree.element.addEventListener('mouseleave', (event:any) => {
this.hideIcon(expand, collapse);
});
}
// hides expand/collapse icon on hovering the mouse
public hideIcon(expand: NodeListOf<Element>, collapse: NodeListOf<Element>) {
for(let i: number = 0; i < collapse.length; i++ ){
collapse[i].setAttribute('style','visibility: hidden');
}
for(let j: number = 0; j < expand.length; j++ ){
expand[j].setAttribute('style','visibility: hidden');
}
}
// shows expand/collapse icon while leaving the mouse
public showIcon(expand: NodeListOf<Element>, collapse: NodeListOf<Element>) {
for(let i: number = 0; i < collapse.length; i++ ){
collapse[i].setAttribute('style',"visibility", "");
}
for(let j: number = 0; j < expand.length; j++ ){
expand[j].setAttribute('style',"visibility", "");
}
}
}
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { TreeViewModule } from '@syncfusion/ej2-angular-navigations';
/**
* Module
*/
@NgModule({
imports: [
BrowserModule,FormsModule,TreeViewModule
],
declarations: [AppComponent],
bootstrap: [AppComponent]
})
export class AppModule { }
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';
enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);