feat(data): show skeleton screens before data is loaded

Closes #4

src/app/_helpers/fake-backend.interceptor.ts

@@ -17,7 +17,7 @@ import {HTTP_INTERCEPTORS, HttpClient,
 import {Injectable} from '@angular/core';
 import {SCIndexResponse, SCThingType} from '@openstapps/core';
 import {Observable, of} from 'rxjs';
-import {map} from 'rxjs/operators';
+import {map, delay} from 'rxjs/operators';
 import {SampleThings} from './data/sample-things';
 
 const sampleIndexResponse: SCIndexResponse = {
@@ -150,12 +150,12 @@ export class FakeBackendInterceptor implements HttpInterceptor {
             return this.sampleFetcher.getSampleThing(request.body.filter.arguments.value)
                     .pipe(map((sampleData: any) => {
               return new HttpResponse({status: 200, body: {data: sampleData}});
-            }));
+            }), delay(1000)); // add delay for skeleton screens to be seen (see !16)
           }
         }
         return this.sampleFetcher.getSampleThings().pipe(map((sampleData: any) => {
           return new HttpResponse({status: 200, body: {data: sampleData}});
-        }));
+        }), delay(1000)); // add delay for skeleton screens to be seen (see !16)
       }
     }
     return next.handle(request);

src/app/modules/data/data.module.ts

@@ -60,6 +60,8 @@ import {SemesterDetailContentComponent} from './types/semester/semester-detail-c
 import {SemesterListItem} from './types/semester/semester-list-item.component';
 import {VideoDetailContentComponent} from './types/video/video-detail-content.component';
 import {VideoListItem} from './types/video/video-list-item.component';
+import {SkeletonListItem} from './elements/skeleton-list-item.component';
+import {SkeletonSimpleCard} from './elements/skeleton-simple-card.component';
 
 @NgModule({
   declarations: [
@@ -69,6 +71,7 @@ import {VideoListItem} from './types/video/video-list-item.component';
     ArticleDetailContentComponent,
     ArticleListItem,
     SimpleCardComponent,
+    SkeletonSimpleCard,
     CatalogDetailContentComponent,
     CatalogListItem,
     DataDetailComponent,
@@ -96,6 +99,7 @@ import {VideoListItem} from './types/video/video-list-item.component';
     PlaceListItem,
     SemesterDetailContentComponent,
     SemesterListItem,
+    SkeletonListItem,
     VideoDetailContentComponent,
     VideoListItem,
   ],

src/app/modules/data/detail/data-detail.component.ts

@@ -28,36 +28,37 @@ export class DataDetailComponent {
   dataProvider: DataProvider;
   item: SCThing;
   language: SCLanguageCode;
+
   constructor(private route: ActivatedRoute, dataProvider: DataProvider, translateService: TranslateService) {
     this.dataProvider = dataProvider;
     this.language = translateService.currentLang as SCLanguageCode;
-
-    // alert(translateService.currentLang);
-
     translateService.onLangChange.subscribe((event: LangChangeEvent) => {
       this.language = event.lang as SCLanguageCode;
     });
   }
+
   /**
    * Provides data item with given UID
    *
    * @param uid Unique identifier of a thing
    */
-  async getItem(uid: SCUuid): Promise<SCThing> {
-    return (await this.dataProvider.get(uid, DataScope.Remote));
+  async getItem(uid: SCUuid): Promise<void> {
+    this.dataProvider.get(uid, DataScope.Remote).then((data) => {
+        this.item = data;
+    });
   }
 
-  async ngOnInit() {
-    this.item = await this.getItem(this.route.snapshot.paramMap.get('uid') || '');
+  ngOnInit() {
+    this.getItem(this.route.snapshot.paramMap.get('uid') || '');
   }
 
   /**
    * Updates the shown thing
    *
-   * @param refresher Refresher component the triggers the update
+   * @param refresher Refresher component that triggers the update
    */
   async refresh(refresher: IonRefresher) {
-    this.item = await this.getItem(this.item.uid);
+    await this.getItem(this.item.uid);
     refresher.complete();
   }
 }

src/app/modules/data/detail/data-detail.html

@@ -7,12 +7,18 @@
     <ion-title text-center>{{'data.detail.TITLE' | translate}}</ion-title>
   </ion-toolbar>
 </ion-header>
-<ion-content padding *ngIf="item">
+<ion-content padding>
   <ion-refresher slot="fixed" (ionRefresh)="refresh($event.target)">
     <ion-refresher-content pullingIcon="arrow-dropdown" pullingText="{{'data.REFRESH_ACTION' | translate}}"
       refreshingText="{{'data.REFRESHING' | translate}}">
     </ion-refresher-content>
   </ion-refresher>
-  <stapps-data-list-item [item]="item"></stapps-data-list-item>
-  <stapps-data-detail-content [item]="item"></stapps-data-detail-content>
+  <ng-container *ngIf="!item">
+    <stapps-skeleton-list-item></stapps-skeleton-list-item>
+    <stapps-skeleton-simple-card></stapps-skeleton-simple-card>
+  </ng-container>
+  <ng-container *ngIf="item">
+    <stapps-data-list-item [item]="item"></stapps-data-list-item>
+    <stapps-data-detail-content [item]="item"></stapps-data-detail-content>
+  </ng-container>
 </ion-content>

src/app/modules/data/elements/skeleton-list-item.component.ts

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2019 StApps
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+import {Component} from '@angular/core';
+
+@Component({
+  selector: 'stapps-skeleton-list-item',
+  templateUrl: 'skeleton-list-item.html',
+})
+export class SkeletonListItem {
+}

src/app/modules/data/elements/skeleton-list-item.html

@@ -0,0 +1,14 @@
+<ion-item>
+<ion-thumbnail slot="start">
+  <ion-skeleton-text animated></ion-skeleton-text>
+</ion-thumbnail>
+  <ion-grid>
+    <ion-row>
+      <ion-col>
+        <h2 class="name"><ion-skeleton-text animated style="width: 80%"></ion-skeleton-text></h2>
+        <p><ion-skeleton-text animated style="width: 80%;"></ion-skeleton-text></p>
+        <ion-note><ion-skeleton-text animated style="width: 20%"></ion-skeleton-text></ion-note>
+      </ion-col>
+    </ion-row>
+  </ion-grid>
+</ion-item>

src/app/modules/data/elements/skeleton-simple-card.component.ts

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2019 StApps
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+import {Component} from '@angular/core';
+
+@Component({
+  selector: 'stapps-skeleton-simple-card',
+  templateUrl: 'skeleton-simple-card.html',
+})
+export class SkeletonSimpleCard {
+}

src/app/modules/data/elements/skeleton-simple-card.html

@@ -0,0 +1,8 @@
+<ion-card>
+  <ion-card-header>
+    <ion-skeleton-text animated style="width: 15%"></ion-skeleton-text>
+  </ion-card-header>
+  <ion-card-content>
+    <p><ion-skeleton-text animated style="width: 85%;"></ion-skeleton-text></p>
+  </ion-card-content>
+</ion-card>

src/app/modules/data/list/data-list.component.ts

@@ -13,7 +13,7 @@
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
 import {Component} from '@angular/core';
-import {AlertController, LoadingController} from '@ionic/angular';
+import {AlertController} from '@ionic/angular';
 import {SCThing} from '@openstapps/core';
 import {Subject} from 'rxjs';
 import {debounceTime, distinctUntilChanged} from 'rxjs/operators';
@@ -25,8 +25,9 @@ import {DataProvider} from '../data.provider';
 })
 export class DataListComponent {
   dataProvider: DataProvider;
-  items: SCThing[] = [];
+  items: SCThing[];
   selectedItem: any;
+  loaded: boolean = false;
 
   size: number = 30;
   from: number = 0;
@@ -34,10 +35,7 @@ export class DataListComponent {
   query: string;
   queryChanged: Subject<string> = new Subject<string>();
 
-  loading: HTMLIonLoadingElement;
-
   constructor(
-    private loadingController: LoadingController,
     private alertController: AlertController,
     dataProvider: DataProvider,
     ) {
@@ -49,31 +47,19 @@ export class DataListComponent {
       .subscribe((model) => {
         this.from = 0;
         this.query = model;
-        this.items = [];
         this.fetchItems();
       });
-
     this.fetchItems();
   }
 
   private async fetchItems(): Promise<any> {
-    if (this.from === 0) {
-      this.loading = await this.loadingController.create();
-      await this.loading.present();
-    }
-
     return this.dataProvider.search({
       from: this.from,
       query: this.query,
       size: this.size,
     } as any).then((result) => {
-      result.data.forEach((item) => {
-        this.items.push(item);
-      });
-
-      if (this.from === 0) {
-        this.loading.dismiss();
-      }
+        this.items = result.data;
+        this.loaded = true;
     }, async (err) => {
       const alert: HTMLIonAlertElement = await this.alertController.create({
         buttons: ['Dismiss'],
@@ -82,8 +68,6 @@ export class DataListComponent {
       });
 
       await alert.present();
-
-      await this.loading.dismiss();
     });
   }
 

src/app/modules/data/list/data-list.html

@@ -12,10 +12,12 @@
 </ion-header>
 
 <ion-content>
-  <ion-list *ngFor="let item of items">
-      <stapps-data-list-item [item]="item"></stapps-data-list-item>
+  <ion-list *ngIf="items">
+    <stapps-data-list-item [item]="item" *ngFor="let item of items"></stapps-data-list-item>
+  </ion-list>
+  <ion-list *ngIf="!items">
+    <stapps-skeleton-list-item *ngFor="let skeleton of [1, 2, 3, 4, 5]"></stapps-skeleton-list-item>
   </ion-list>
-
   <ion-infinite-scroll (ionInfinite)="loadMore($event)">
     <ion-infinite-scroll-content></ion-infinite-scroll-content>
   </ion-infinite-scroll>