title: Ionic 2, how to properly use alert
body: <p>I am programming using Ionic 2, and I want to show a pop-up alert when a button is clicked.</p>
  
  <p>This is the code in my <em>home.html</em>:</p>
  
  <pre><code>&lt;button (click)='openFilters()'&gt;CLICK&lt;/button&gt;
  </code></pre>
  
  <p>And in my <em>home.ts</em></p>
  
  <pre><code>import {Component} from '@angular/core';
  import {Page, NavController, Alert} from 'ionic-angular';
  
  @Component({
    templateUrl: 'build/pages/home/home.html'
  })
  export class HomePage {
    constructor(nav: NavController, alertCtrl: AlertController) {
  
    }
  
    openFilters() {
      let alert = this.alertCtrl.create({
          title: 'Low battery',
          subTitle: '10% of battery remaining',
          buttons: ['Dismiss']
      });
      alert.present();
    }
  }
  </code></pre>
  
  <p>I have read some StackOverflow questions on this topic and tried to implement it like this:</p>
  
  <pre><code>openFilters() {
      let alert:Alert = Alert.create({
          title: 'Low battery',
          subTitle: '10% of battery remaining',
          buttons: ['Dismiss']
      });
      this.nav.present(alert);
    }
  </code></pre>
  
  <p>Still, I accomplished nothing; I get errors.</p>