ionic 3 photo library image not displayed on img tag

Question

I followed the instruction on ionic doc here and Github doc here. Up to now I can retrieve all library item info. But I never succeed in displaying the photos on img tab.

Here are my home.ts:

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';

import { PhotoLibrary } from '@ionic-native/photo-library';
import { Platform } from 'ionic-angular';
import { ChangeDetectorRef } from '@angular/core';
import { DomSanitizer, SafeUrl } from '@angular/platform-browser';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

library:any;

constructor(public navCtrl: NavController, private photoLibrary: PhotoLibrary, private platform: Platform,
    private cd: ChangeDetectorRef, private sanitizer: DomSanitizer) {
    this.library = [];
    this.fetchPhotos();
}

fetchPhotos() {

    this.platform.ready().then(() => {

        this.library = [];
        this.photoLibrary.requestAuthorization().then(() => {
            this.photoLibrary.getLibrary({ 
                thumbnailWidth: 512, 
                thumbnailHeight: 384, 
                itemsInChunk: 100, 
                chunkTimeSec: 0.5, 
                useOriginalFileNames: false
            }).subscribe({
                next: (chunk) => {
                    this.library = this.library.concat(chunk);
                    //this.library = this.library.slice(0, 9); // To take top 10 images
                    this.cd.detectChanges();
                },
                error: (err: string) => {
                    if (err.startsWith('Permission')) {
                        console.log('permissions weren\'t granted')
                    } else { // Real error
                        console.log('getLibrary error: ');
                        console.log(err);
                    }
                },
                complete: () => {
                    // Library completely loaded
                    console.log('done getting photos');
                }
            });
        });
    });

}

imgUrl(imgUrl) {
    let url: SafeUrl = this.sanitizer.bypassSecurityTrustUrl(imgUrl);
    return url;
}

}

Here is home.html:

<ion-content padding>
  <img *ngFor="let libraryItem of library" [src]="imgUrl(libraryItem.thumbnailURL)" />
</ion-content>

I always got empty img box with src=null. If I don't use DomSantinizer, it will show the warning for all photos:

WARNING: sanitizing unsafe URL value cdvphotolibrary://thumbnail?photoId=xxx&width=xx&height=xx&quality=0.5

(see http://g.co/ng/security#xss)

My ionic info is: cli packages: (/usr/local/lib/node_modules)

@ionic/cli-utils  : 1.15.2
ionic (Ionic CLI) : 3.15.2

global packages:

cordova (Cordova CLI) : 7.1.0 

local packages:

@ionic/app-scripts : 3.0.1
Cordova Platforms  : android 6.3.0 ios 4.5.2
Ionic Framework    : ionic-angular 3.8.0

System:

ios-deploy : 1.9.2 
ios-sim    : 5.0.13 
Node       : v7.4.0
npm        : 5.5.1 
OS         : macOS Sierra
Xcode      : Xcode 8.3.2 Build version 8E2002 

Anybody please help?? Thanks!!

Answer 1

I think I've found a solution here - change WKWebView to UIWebView. Then the pictures show up.

I found the reason in this post. Also ionic official doc also proves that currently WKWebView doesn't support local files.

I hope my post will help someone with similar situation, and do hope ionic team could soon improve WKWebView in terms of custom schema file path. Happy coding~!

Answer 2

This works like a charm:-

If you are using wkwebview(which is now default for new apps) then follow below steps,

import { normalizeURL} from ‘ionic-angular’;

store your image path in some new variable.
var imagePath = this.file.dataDirectory + “test.png”;
this.tempImagePath = normalizeURL(imagePath);

then in your html file,
use tempImagePath as image src.

Source: https://forum.ionicframework.com/t/downloaded-image-is-not-displayed-ionic-3-8/110912/2

To see if WKWebview is installed correctly, try adding this to your main app component:

if (window.indexedDB) {
  console.log('I have WKWebview installed!');
} else {
  console.log('I have UIWebView installed!');
}