NativeScript/tests/app/ui/tab-view/tab-view-tests-native.android.ts

import * as tabViewModule from "ui/tab-view";

export function getNativeTabCount(tabView: tabViewModule.TabView): number {
    var pagerAdapter: android.support.v4.view.PagerAdapter = (<any>tabView)._pagerAdapter;
    return pagerAdapter ? pagerAdapter.getCount() : 0;
}

export function selectNativeTab(tabView: tabViewModule.TabView, index: number): void {
    var viewPager: android.support.v4.view.ViewPager = (<any>tabView)._viewPager;
    if (viewPager) {
        viewPager.setCurrentItem(index);
    }
}

export function getNativeSelectedIndex(tabView: tabViewModule.TabView): number {
    var viewPager: android.support.v4.view.ViewPager = (<any>tabView)._viewPager;
    return viewPager ? viewPager.getCurrentItem() : -1;
}