在带有Angular的NativeScript中，如何获取接口元素的ID? [英] In NativeScript with Angular, how can I get an interface element the id?

问题描述

我试图避免在NativeScript应用程序中发生意外行为.

I'm trying to avoid unexpected behavior in a NativeScript application.

当我进入具有搜索字段(SearchBar)的任何屏幕时，系统会自动将焦点放在搜索字段上.

When I walk into any screen that has a search field (SearchBar) system puts the focus on the search field automatically.

然后，我得到了一位朋友的帮助，后者为我提供了解决此问题的功能.但是我现在面临的问题是我无法获取接口元素.我有以下代码:

Then I got help with a friend who gave me a function to solve this problem. But the problem I'm facing right now is that I can not get the interface element. I have the following code:

import {Component} from "@angular/core";
import {Page} from "ui/page";
import frame = require("ui/frame");

@Component({
    selector: "clientes",
    templateUrl: "pages/clientes/clientes.html",
    styleUrls: ["pages/clientes/clientes.common.css",
    "pages/clientes/clientes.css"]
})

export class ClientesPage {

    page;

    constructor(private _router: Router) {
        this.page = <Page>frame.topmost().currentPage;
        this.removeSearchFocus();
    }

    removeSearchFocus() {
        var parent = this.page.getViewById('box-lista');
        var searchBar = this.page.getViewById('barra-busca');

        console.log(JSON.stringify(parent)); // UNDEFINED
        console.log(JSON.stringify(searchBar)); // UNDEFINED

        if (parent.android) {
            parent.android.setFocusableInTouchMode(true);
            parent.android.setFocusable(true);
            searchBar.android.clearFocus();
        }

    }
}

然后我有了模板:

<Page.actionBar>
    <ActionBar title="Clientes"></ActionBar>
</Page.actionBar>

<StackLayout orientation="vertical" id="box-lista">
    <SearchBar hint="Buscar" cssClass="mh mv" id="barra-busca"></SearchBar>
</StackLayout>

我的目标是获取搜索字段的自动焦点，但无法获取界面元素.

My goal is to get the auto focus of the search field, but I can not get the interface element.

推荐答案

在此之上扩展Nikolay的答案，以使用@ViewChild将#foo添加到您的堆栈布局中，使其看起来像:

to expand on Nikolay's answer above this to use @ViewChild add #foo to your stack layout so it looks like:

<StackLayout #foo ....

然后:

@ViewChild('foo') stackLayout: ElementRef;

ngAfterViewInit() {
    let yourStackLayoutInstance = this.stackLayout.nativeElement;
} 

它不会通过ID来获取元素，但这是ng2与元素进行交互的方式，它可以使您的代码更松散地耦合到DOM.

it won't get the element by ID but this is the more ng2 way of interacting with elements and keeps your code more loosely coupled to the DOM.

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