fix(nav): correctly set zIndex when there's a previous view

ionic/components/alert/test/dismiss/index.ts

@@ -13,10 +13,6 @@ export class E2EPage {
       title: 'Not logged in',
       message: 'Sign in to continue.',
       buttons: [
-        {
-          text: 'Cancel',
-          role: 'cancel'
-        },
         {
           text: 'Sign in',
           handler: () => {
@@ -45,7 +41,39 @@ export class E2EPage {
     </ion-content>
   `
 })
-class AnotherPage {}
+class AnotherPage {
+
+  constructor(private nav: NavController) {}
+
+  onPageDidEnter() {
+    this.showConfirm();
+  }
+
+  showConfirm() {
+    const alert = Alert.create({
+      title: `Hi there`,
+      buttons: [
+        {
+          text: 'Go Back',
+          role: 'cancel',
+          handler: () => {
+            alert.dismiss().then(() => {
+              this.nav.pop();
+            })
+          }
+        },
+        {
+          text: 'Stay Here',
+          handler: () => {
+            console.log('Stay Here');
+          }
+        }
+      ]
+    });
+    this.nav.present(alert);
+  }
+
+}
 
 
 @App({

ionic/components/nav/nav-controller.ts

@@ -1641,7 +1641,19 @@ export class NavController extends Ion {
     if (enteringView) {
       // get the leaving view, which could be in various states
       if (!leavingView || !leavingView.isLoaded()) {
+        // the leavingView is a mocked view, either we're
+        // actively transitioning or it's the initial load
+
+        var previousView = this.getPrevious(enteringView);
+        if (previousView && previousView.isLoaded()) {
+          // we found a better previous view to reference
+          // use this one instead
+          enteringView.setZIndex(previousView.zIndex + 1, this._renderer);
+
+        } else {
+          // this is the initial view
           enteringView.setZIndex(INIT_ZINDEX, this._renderer);
+        }
 
       } else if (direction === 'back') {
         // moving back

ionic/components/nav/test/nav-controller.spec.ts

@@ -585,7 +585,33 @@ export function run() {
     });
 
     describe('_setZIndex', () => {
-      it('should set zIndex 10 on first entering view', () => {
+
+      it('should set zIndex off of the previous view to the entering view  is loaded and the leavingView is not loaded', () => {
+        let leavingView = new ViewController();
+        leavingView.zIndex = 100;
+        leavingView._loaded = true;
+        let enteringView = new ViewController();
+        enteringView.setPageRef({});
+
+        nav._views = [leavingView, enteringView];
+
+        nav._setZIndex(enteringView, leavingView, 'forward');
+        expect(enteringView.zIndex).toEqual(101);
+      });
+
+      it('should set zIndex 100 when leaving view is not loaded', () => {
+        let leavingView = new ViewController();
+        leavingView._loaded = false;
+        let enteringView = new ViewController();
+        enteringView.setPageRef({});
+
+        nav._views = [leavingView, enteringView];
+
+        nav._setZIndex(enteringView, leavingView, 'forward');
+        expect(enteringView.zIndex).toEqual(100);
+      });
+
+      it('should set zIndex 100 on first entering view', () => {
         let enteringView = new ViewController();
         enteringView.setPageRef({});
         nav._setZIndex(enteringView, null, 'forward');