您好，我正在尝试使用Ionic-v4中的File Opener和Document Viewer插件，它工作正常，但是我在Ionic-v3中实现了TypeError。
我正在共享Ionic的配置和我们的系统。
Ionic:
ionic (Ionic CLI) : 4.5.0 (/usr/local/lib/node_modules/ionic)
Ionic Framework : ionic-angular 3.9.3
@ionic/app-scripts : 3.2.1
Cordova:
cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
Cordova Platforms : android 7.1.4, ios 4.5.5
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 3.1.2, (and 7 other plugins)
System:
Android SDK Tools : 26.1.1 (/Users/apple/Library/Android/sdk)
ios-deploy : 1.9.4
NodeJS : v10.14.1 (/usr/local/bin/node)
npm : 6.5.0
OS : macOS Mojave
Xcode : Xcode 10.1 Build version 10B61
我在下面分享错误：
[Error] ERROR – TypeError: Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"]) is not a function. (In 'Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"])(this, "documentsDirectory")', 'Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"])' is an instance of Object)
TypeError: Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"]) is not a function. (In 'Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"])(this, "documentsDirectory")', 'Object(__WEBPACK_IMPORTED_MODULE_1__ionic_native_core__["cordovaPropertyGet"])' is an instance of Object)get — index.js:697downloadOpenPdf — home.ts:46(anonymous function)callWithDebugContext — core.js:15098dispatchEvent — core.js:10004(anonymous function) — platform-browser.js:2628onInvokeTask — core.js:4751runTask — polyfills.js:3:10845invokeTask — polyfills.js:3:16802p — polyfills.js:2:27655v — polyfills.js:2:27895
error
View_HomePage_0 (HomePage.ngfactory.js:25)
logError (vendor.js:15363)
(anonymous function)
handleError (vendor.js:1835)
handleError (vendor.js:122728)
dispatchEvent (vendor.js:10333)
(anonymous function) (vendor.js:39445)
onInvokeTask (vendor.js:5076)
runTask (polyfills.js:3:10845)
invokeTask (polyfills.js:3:16802)
p (polyfills.js:2:27655)
v (polyfills.js:2:27895)
那我该怎么办？
谢谢！