Add Layer buttons above the keyboard

src/main-app.component.ts

@@ -1,15 +1,84 @@
-import { Component, OnInit } from 'angular2/core';
+import { Component, OnInit, AfterViewInit, Renderer, ViewChildren, QueryList, ElementRef} from 'angular2/core';
 
 import {SvgKeyboardComponent} from './components/svg-keyboard.component';
 
 @Component({
     selector: 'main-app',
-    template: '<svg-keyboard></svg-keyboard>',
+    template:
+    `   <div>
+            <button #baseButton type="button" class="btn btn-default btn-lg btn-primary" (click)="selectLayer(0)">
+                Base
+            </button>
+            <button #modButton type="button" class="btn btn-default btn-lg" (click)="selectLayer(1)">
+                Mod
+            </button>
+            <button #fnButton type="button" class="btn btn-default btn-lg" (click)="selectLayer(2)">
+                Fn
+            </button>
+            <button #mouseButton type="button" class="btn btn-default btn-lg" (click)="selectLayer(3)">
+                Mouse
+            </button>
+        </div>
+        <div>
+            <svg-keyboard></svg-keyboard>
+        </div>
+    `,
+    styles:
+    [`
+        :host {
+            display: flex;
+            flex-direction: column;
+        }
+
+        :host > div:first-child {
+            display: flex;
+            flex: 1;
+            align-items: center;
+            justify-content: center;
+        }
+
+        button {
+            margin: 2px;
+        }
+
+        :host > div:last-child {
+            display: flex;
+            flex: 5;
+            justify-content: center;
+        }
+
+       :host > div:last-child > svg-keyboard {
+           width: 80%;
+       }
+    `],
     directives: [SvgKeyboardComponent]
 })
-export class MainAppComponent implements OnInit {
-    constructor() { }
+export class MainAppComponent implements OnInit, AfterViewInit {
+    @ViewChildren('baseButton,modButton,fnButton,mouseButton')
+    buttonsQueryList: QueryList<ElementRef>;
+
+    private buttons: ElementRef[];
+    private selectedLayerIndex: number;
+
+    constructor(private renderer: Renderer) {
+        this.buttons = [];
+        this.selectedLayerIndex = -1;
+    }
 
     ngOnInit() { }
 
+    ngAfterViewInit() {
+        this.buttons = this.buttonsQueryList.toArray();
+        this.selectedLayerIndex = 0;
+    }
+
+    /* tslint:disable:no-unused-variable */
+    /* selectLayer is used in the template string */
+    private selectLayer(index: number): void {
+        /* tslint:enable:no-unused-variable */
+        this.renderer.setElementClass(this.buttons[this.selectedLayerIndex].nativeElement, 'btn-primary', false);
+        this.renderer.setElementClass(this.buttons[index].nativeElement, 'btn-primary', true);
+        this.selectedLayerIndex = index;
+    }
+
 }