【已解决】Ionic 3真机中Http subscribe函数无法调用问题

I'm trying to access a local web service from my Ionic app. The service works perfectly in the browser, but when running on a physical Android device, the subscribe function on my Http calls doesn't trigger at all.

Here's what I've tested:

• When I only call get/post without using subscribe, the code runs fine on both browser and device.
• Any code using Observer/subscribe or Promises completely fails on the device—no console output, no toast notifications, nothing. This happens regardless of whether I use ionic cordova run android, Ionic View, or the Ionic Dev app.

Test Code Scenarios #

1. Only calling get (works everywhere)

var result = this.http.get('someurl for list of data'); 
console.log(result);

This outputs [object Object] in both browser console and device logs when the button is clicked.

2. Using subscribe (only works in browser)

var res = this.http.get(this.partnersUrl).subscribe(result => { 
  console.log(result); 
})

This logs the result in the browser console, but on the device, nothing happens when I click the button—no console output, no toast (I added a toast test which only shows up in the browser).

Update: Root Cause Found #

Sorry for the trouble everyone. I've identified the issue: the local subdomain I'm using is configured in my server's hosts file, but the Android device's hosts file doesn't have that entry. That's why the requests were failing silently on the device. Thanks to everyone who took the time to look into this.

I'm stuck and can't proceed with development until this is resolved. Any help would be greatly appreciated!

Environment Info #

• cli packages: (C:\Users\danis\AppData\Roaming\nvm\v6.11.5\node_modules)
  • @ionic/cli-utils : 1.19.0
  • ionic (Ionic CLI) : 3.19.0
• global packages:
  • cordova (Cordova CLI) : 7.1.0
• local packages:
  • @ionic/app-scripts : 3.1.2
  • Cordova Platforms : android 6.3.0
  • Ionic Framework : ionic-angular 3.9.2
• System:
  • Android SDK Tools : 26.0.1
  • Node : v6.11.5
  • npm : 3.10.10
  • OS : Windows 10
• Environment Variables:
  • ANDROID_HOME : C:\Users\danis\AppData\Local\Android\sdk
• Misc:
  • backend : pro

Ionic Plugins List #

cordova-plugin-add-swift-support 1.7.1 "AddSwiftSupport"
cordova-plugin-device 1.1.4 "Device"
cordova-plugin-ionic 2.0.4 "IonicCordova"
cordova-plugin-ionic-webview 1.1.16 "cordova-plugin-ionic-webview"
cordova-plugin-splashscreen 4.0.3 "Splashscreen"
cordova-plugin-whitelist 1.3.1 "Whitelist"
ionic-plugin-keyboard 2.2.1 "Keyboard"

config.xml #

<?xml version='1.0' encoding='utf-8'?>
<widget id="io.ionic.starter" version="0.0.1" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
<name>Some app</name>
<description>An awesome Ionic/Cordova app.</description>
<author email="hi@ionicframework" href="http://ionicframework.com/">Ionic Framework Team</author>
<content src="index.html" />
<access origin="*" />
<allow-intent href="http://*/*" />
<allow-intent href="https://*/*" />
<allow-intent href="tel:*" />
<allow-intent href="sms:*" />
<allow-intent href="mailto:*" />
<allow-intent href="geo:*" />
<preference name="ScrollEnabled" value="false" />
<preference name="android-minSdkVersion" value="16" />
<preference name="BackupWebStorage" value="none" />
<preference name="SplashMaintainAspectRatio" value="true" />
<preference name="FadeSplashScreenDuration" value="300" />
<preference name="SplashShowOnlyFirstTime" value="false" />
<preference name="SplashScreen" value="screen" />
<preference name="SplashScreenDelay" value="3000" />
<platform name="android">
<allow-intent href="market:*" />
<icon density="ldpi" src="resources/android/icon/drawable-ldpi-icon.png" />
<icon density="mdpi" src="resources/android/icon/drawable-mdpi-icon.png" />
<icon density="hdpi" src="resources/android/icon/drawable-hdpi-icon.png" />
<icon density="xhdpi" src="resources/android/icon/drawable-xhdpi-icon.png" />
<icon density="xxhdpi" src="resources/android/icon/drawable-xxhdpi-icon.png" />
<icon density="xxxhdpi" src="resources/android/icon/drawable-xxxhdpi-icon.png" />
<splash density="land-ldpi" src="resources/android/splash/drawable-land-ldpi-screen.png" />
<splash density="land-mdpi" src="resources/android/splash/drawable-land-mdpi-screen.png" />
<splash density="land-hdpi" src="resources/android/splash/drawable-land-hdpi-screen.png" />
<splash density="land-xhdpi" src="resources/android/splash/drawable-land-xhdpi-screen.png" />
<splash density="land-xxhdpi" src="resources/android/splash/drawable-land-xxhdpi-screen.png" />
<splash density="land-xxxhdpi" src="resources/android/splash/drawable-land-xxxhdpi-screen.png" />
<splash density="port-ldpi" src="resources/android/splash/drawable-port-ldpi-screen.png" />
<splash density="port-mdpi" src="resources/android/splash/drawable-port-mdpi-screen.png" />
<splash density="port-hdpi" src="resources/android/splash/drawable-port-hdpi-screen.png" />
<splash density="port-xhdpi" src="resources/android/splash/drawable-port-xhdpi-screen.png" />
<splash density="port-xxhdpi" src="resources/android/splash/drawable-port-xxhdpi-screen.png" />
<splash density="port-xxxhdpi" src="resources/android/splash/drawable-port-xxxhdpi-screen.png" />
</platform>
<platform name="ios">
<allow-intent href="itms:*" />
<allow-intent href="itms-apps:*" />
<icon height="57" src="resources/ios/icon/icon.png" width="57" />
<icon height="114" src="resources/ios/icon/icon@2x.png" width="114" />
<icon height="40" src="resources/ios/icon/icon-40.png" width="40" />
<icon height="80" src="resources/ios/icon/icon-40@2x.png" width="80" />
<icon height="120" src="resources/ios/icon/icon-40@3x.png" width="120" />
<icon height="50" src="resources/ios/icon/icon-50.png" width="50" />
<icon height="100" src="resources/ios/icon/icon-50@2x.png" width="100" />
<icon height="60" src="resources/ios/icon/icon-60.png" width="60" />
<icon height="120" src="resources/ios/icon/icon-60@2x.png" width="120" />
<icon height="180" src="resources/ios/icon/icon-60@3x.png" width="180" />
<icon height="72" src="resources/ios/icon/icon-72.png" width="72" />
<icon height="144" src="resources/ios/icon/icon-72@2x.png" width="144" />
<icon height="76" src="resources/ios/icon/icon-76.png" width="76" />
<icon height="152" src="resources/ios/icon/icon-76@2x.png" width="152" />
<icon height="167" src="resources/ios/icon/icon-83.5@2x.png" width="167" />
<icon height="29" src="resources/ios/icon/icon-small.png" width="29" />
<icon height="58" src="resources/ios/icon/icon-small@2x.png" width="58" />
<icon height="87" src="resources/ios/icon/icon-small@3x.png" width="87" />
<icon height="1024" src="resources/ios/icon/icon-1024.png" width="1024" />
<splash height="1136" src="resources/ios/splash/Default-568h@2x~iphone.png" width="640" />
<splash height="1334" src="resources/ios/splash/Default-667h.png" width="750" />
<splash height="2208" src="resources/ios/splash/Default-736h.png" width="1242" />
<splash height="1242" src="resources/ios/splash/Default-Landscape-736h.png" width="2208" />
<splash height="1536" src="resources/ios/splash/Default-Landscape@2x~ipad.png" width="2048" />
<splash height="2048" src="resources/ios/splash/Default-Landscape@~ipadpro.png" width="2732" />
<splash height="768" src="resources/ios/splash/Default-Landscape~ipad.png" width="1024" />
<splash height="2048" src="resources/ios/splash/Default-Portrait@2x~ipad.png" width="1536" />
<splash height="2732" src="resources/ios/splash/Default-Portrait@~ipadpro.png" width="2048" />
<splash height="1024" src="resources/ios/splash/Default-Portrait~ipad.png" width="768" />
<splash height="960" src="resources/ios/splash/Default@2x~iphone.png" width="640" />
<splash height="480" src="resources/ios/splash/Default~iphone.png" width="320" />
<splash height="2732" src="resources/ios/splash/Default@2x~universal~anyany.png" width="2732" />
</platform>
<plugin name="cordova-plugin-whitelist" spec="1.3.1" />
<plugin name="cordova-plugin-device" spec="1.1.4" />
<plugin name="cordova-plugin-splashscreen" spec="~4.0.1" />
<plugin name="cordova-plugin-ionic-webview" spec="^1.1.11" />
<plugin name="ionic-plugin-keyboard" spec="^2.2.1" />
<engine name="android" spec="~6.3.0" />
<allow-navigation href="http://localhost:8100" />
<allow-navigation href="http://192.168.0.10:8100" />
<allow-navigation href="http://*/*" />
<allow-navigation href="https://*/*" />
<plugin name="cordova-plugin-ionic" spec="^2.0.4">
<variable name="APP_ID" value="84027630" />
<variable name="CHANNEL_NAME" value="Master" />
<variable name="UPDATE_METHOD" value="background" />
<variable name="UPDATE_API" value="https://api.ionicjs.com" />
<variable name="MAX_STORE" value="2" />
</plugin>
</widget>

内容的提问来源于stack exchange，提问作者Danish Jamil