Question

我正试图通过ionic V4将图片从互联网下载到手机上，然后使用File插件将其直接从本机文件系统中显示出来。

很遗憾，我无法在V4中使用它，但是在V3中可以使用。我认为V4解释路径以将其绑定到src attribute（？）

的方式可能存在问题。

我编写了一个程序来对其进行测试。

TS文件：

import { Component, OnInit } from '@angular/core';
import { FileTransfer, FileTransferObject } from '@ionic-native/file-transfer/ngx';
import { File } from '@ionic-native/file/ngx'

@Component({
  selector: 'app-scratch2',
  templateUrl: './scratch2.page.html',
  styleUrls: ['./scratch2.page.scss'],
})
export class Scratch2Page implements OnInit {
  private address: string = null;
  private path: string = null;
  private fileNumber = 1;
  private latest = null;
  private toggle = false;

  constructor(
    private fileX: FileTransfer,
    private file: File
  ) { 
    this.path = this.file.dataDirectory + "files/";
  }

  ngOnInit() {
    let filename = this.nameFile()
    this.latest = this.nameFix(filename)
    console.log("1the filename that is returned is ********** ", filename)
  }

  nameFile(){
    let filename = this.path + "file" + this.fileNumber
    return filename
  }

  nameFix(filename){
    return filename.replace(/file:\/\//g, "")
  }

  downloadFile() {
    let filename = this.nameFile();
    console.log("2the filename that is returned is ********** ", filename)
    console.log("Entered download File with url: ", this.address)
    let url = this.address
    const fileTransfer: FileTransferObject = this.fileX.create();
    fileTransfer.download(url, filename).then((entry) => {
        console.log('fileTransfer.download data ** ** ** **:' + JSON.stringify(entry));
        this.fileNumber += 1;
        this.latest = this.nameFix(filename)
    }, (err) => {
      // handle error
      console.log("downloadfile() error: " + JSON.stringify(err));
    });
  }

  toggleToggle(){
    this.toggle = !this.toggle;

  }

}

这是HTML文件：

    <ion-header>
  <ion-toolbar>
      <ion-buttons slot="start">
          <ion-back-button defaultHref="/"></ion-back-button>
        </ion-buttons>
    <ion-title>scratch2</ion-title>
  </ion-toolbar>
  <ion-toolbar>{{latest}} {{toggle}}</ion-toolbar>
</ion-header>

<ion-content padding>
    <ion-item>
        <ion-label>Address</ion-label>
        <ion-input placeholder="Enter address" [(ngModel)]="address"></ion-input>
      </ion-item>
      <ion-button (click)="downloadFile()"> Download from address</ion-button>
      <ion-button (click)="toggleToggle()">Toggle</ion-button>

    <img *ngIf="toggle" [src]="latest"/>
</ion-content>

任何帮助将不胜感激

Answer 1

在这里回答我自己的问题……这就是我所发现的。

文件结构确实发生了变化，并且文件本身可以通过Web服务器访问，而不是直接访问。在以下链接中对此进行了讨论：https://ionicframework.com/docs/wkwebview/

其归结为：当您要将文件下载到手机上时，可以通过以下两个路径进行操作，一个路径用于下载文件，另一个路径用于显示下载的文件：

this.downloadPath = this.file.dataDirectory + "filename.jpg"
this.showFilePath = normalizeURL(this.file.dataDirectory + "filename.jpg")

使用以下方法导入normalizeURL：import {normalizeURL} from“ ionic-angular”;

因此，我重写了上面的代码，使其看起来像这样：

TS文件

import { Component, OnInit } from '@angular/core';
import { FileTransfer, FileTransferObject } from '@ionic-native/file-transfer/ngx';
import { File } from '@ionic-native/file/ngx'
import { normalizeURL } from "ionic-angular";

@Component({
  selector: 'app-scratch2',
  templateUrl: './scratch2.page.html',
  styleUrls: ['./scratch2.page.scss'],
})
export class Scratch2Page implements OnInit {
  private address: string = null;
  private path: string = null;
  private toggle = false;
  private showPath = null;
  private downloadPath = null

  constructor(
    private fileX: FileTransfer,
    private file: File
  ) {
    this.path = this.file.dataDirectory + "files/";
    this.downloadPath = this.path + "beer.jpg"
    this.showPath = normalizeURL(this.path + "beer.jpg")
  }
  ngOnInit() {
  }

  downloadFile() {
    console.log("Entered download File with url: ", this.address)
    let url = this.address
    const fileTransfer: FileTransferObject = this.fileX.create();
    fileTransfer.download(url, this.downloadPath).then((entry) => {
      console.log('fileTransfer.download data ** ** ** **:' + JSON.stringify(entry));
    }, (err) => {
      console.log("downloadfile() error: " + JSON.stringify(err));
    });
  }

  toggleToggle() {
    this.toggle = !this.toggle;
  }
}

HTML文件

<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button defaultHref="/"></ion-back-button>
    </ion-buttons>
    <ion-title>scratch2</ion-title>
  </ion-toolbar>
  <ion-toolbar>toggle:{{toggle}} <br><br> download path:<br>{{downloadPath}} <br><br> Show path:<br>{{showPath}}</ion-toolbar>
</ion-header>
<ion-content padding>
  <ion-item>
    <ion-label>http address of jpg:</ion-label>
    <ion-input placeholder="Enter address" [(ngModel)]="address"></ion-input>
  </ion-item>
  <ion-button (click)="downloadFile()"> download jpg</ion-button>
  <ion-button (click)="toggleToggle()">Toggle</ion-button>
  <img *ngIf="toggle" src="{{showPath}}" />
</ion-content>

在iPhone模拟器上，下载路径开始如下：

file:///Users/myUserName/Library/etc etc etc

，显示文件路径开始如下：

http://localhost:8080/_file_/Users/myUserName/Library/etc etc etc

Ionic V4（测试版11）文件插件似乎不适用于V4

1 个答案: