Angular

How to convert div containing an image into a png in Ionic/Angular

You can do this by installing the html2canvas library via `npm i html2canvas`
But you have to remember to useCORS if your div includes an externally located image! very important.


html2canvas(this.screen.nativeElement, {
      useCORS: true, //By passing this option in function Cross origin images will be rendered properly in the downloaded version of the PDF
    }).then(canvas => {
      this.canvas.nativeElement.src = canvas.toDataURL();
      this.downloadLink.nativeElement.href = canvas.toDataURL('image/png');
      this.downloadLink.nativeElement.download = new Date() + '.png';
      this.downloadLink.nativeElement.click();
    });

How to fix ion-checkbox stealing clicks on ion-item elements

How to fix ion-checkbox stealing clicks on ion-item elements.

I found this annoying issue with Ionic 5 where clicking on ion-label inside ion-item can’t be clicked if there is also an ion-checkbox element.

You have to change the z-index on the element you want clickable.

// component css
ion-label{
   z-index: 3;
}

You can also disable button property on ion-item, check the docs here.

You can also apply this to any other element you want to use inside ion-item. Good luck!

Implement App Tracking Transparency for Ionic Angular and Cordova iOS app

How to use the https://github.com/chemerisuk/cordova-plugin-idfa plugin in Ionic v3.

I had some issues using the example provided so I had to call the exec directly:

// first install the plugin
// cordova plugin add cordova-plugin-idfa
// npm i cordova-plugin-idfa --save

// add permissions to config.xml under ios platform
<platform name="ios">
    <edit-config target="NSUserTrackingUsageDescription" file="*-Info.plist" mode="merge">
        <string> My tracking usage description </string>
    </edit-config>
</platform>


// has to be called after platform is ready
// this.platform.ready().then(() => {}

askTrackingPermission() {
    if (this.platform.is('cordova') && this.platform.is('ios')) {

      if (window.cordova) {
        console.log('trying to request permission ');
        window.cordova.exec(win, fail, 'idfa', "requestPermission", []);
      }
    }

    function win(res) {
      console.log('success ' + JSON.stringify(res));
    }
    function fail(res) {
      console.log('fail ' + JSON.stringify(res));
    }
  }

readTrackingPermission() {

    if (this.platform.is('cordova') && this.platform.is('ios')) {

      if (window.cordova) {
        window.cordova.exec(win, fail, 'idfa', "getInfo", []);
      }
    }

    function win(res) {
      console.log('success  ' + JSON.stringify(res));
    }
    function fail(res) {
      console.log('fail ' + JSON.stringify(res));
    }
  }

Also, you can only test this from the iOS simulator (or device) running 14.5.1+ iOS. In your iOS device settings check privacy->tracking (setting) it has to be allowed to ask. And you will only be able to ask the user once.

Good luck!

How To Create Downloadable CSV File in JS/Angular

 
import { SecurityContext } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';
private sanitizer: DomSanitizer;

downloadCSV() {

  let blob = new Blob([yourdata], { type: 'text/csv' });
  let urlPath = this.sanitizer.sanitize(SecurityContext.URL,
this.sanitizer.bypassSecurityTrustResourceUrl(window.URL.createObjectURL(blob)));
    
  let tempLink = document.createElement('a');
  tempLink.href = urlPath;
  tempLink.setAttribute('download', 'download.csv');
  tempLink.click();
}

Google Android Play Store Target API Requirement Change

From Google:

Hello Google Play Developer,

This is a reminder that starting November 1, 2019, updates to apps and games on Google Play will be required to target Android 9 (API level 28) or higher. After this date, the Play Console will prevent you from submitting new APKs with a targetSdkVersion less than 28.

Configuring your app to target a recent API level ensures that users benefit from significant security and performance improvements, while still allowing your app to run on older Android versions (down to the minSdkVersion).

Android 9 (API level 28) introduces a number of changes to the Android system. The following behavior changes apply exclusively to apps that are targeting API level 28 or higher. Apps that set targetSdkVersion to API level 28 or higher must modify their apps to support these behaviors properly, where applicable to the app.

To target the api in your Cordova app set these min and target version in config.xml

    <preference name="android-minSdkVersion" value="23" />
    <preference name="android-targetSdkVersion" value="28" />

How to Implement Merge Sort in JavaScript

How to Implement Merge Sort in JavaScript the easy way.


// Split the array into halves and merge them recursively 
function mergeSort (arr) {
  if (arr.length === 1) {
    // return once we hit an array with a single item
    return arr
  }

  const middle = Math.floor(arr.length / 2) // get the middle item of the array rounded down
  const left = arr.slice(0, middle) // items on the left side
  const right = arr.slice(middle) // items on the right side

  return merge(
    mergeSort(left),
    mergeSort(right)
  )
}

// compare the arrays item by item and return the concatenated result
function merge (left, right) {
  let result = []
  let indexLeft = 0
  let indexRight = 0

  while (indexLeft < left.length && indexRight < right.length) {
    if (left[indexLeft] < right[indexRight]) {
      result.push(left[indexLeft])
      indexLeft++
    } else {
      result.push(right[indexRight])
      indexRight++
    }
  }

  return result.concat(left.slice(indexLeft)).concat(right.slice(indexRight))
}

const list = [2, 5, 1, 3, 7, 2, 3, 8, 6, 3];
console.log(mergeSort(list)) // [ 1, 2, 2, 3, 3, 3, 5, 6, 7, 8 ];

iOS Deprecated API Usage Warning Ionic using UIWebView

Apple will no longer support web apps that use UIWebView. The apps and libraries need to be migrated to use WkWebView.

The latest Ionic already uses WkWebView, but several Cordova plugins still rely on UIWebView which is a problem.

https://ionicframework.com/docs/v3/wkwebview/

If you’re using Ionic you need to upgrade to iOS Cordova 5

cordova platform remove ios
cordova platform add ios@5.0.0

Also you might need to remove additional plugins that use UIWebView such as inappbrowser. 

cordova plugin rm cordova-plugin-inappbrowser

More information about the breaking changes can be found here:

https://cordova.apache.org/news/2018/08/01/future-cordova-ios-webview.html

How to Enable Preflight CORS in PHP for Angular HTTP requests

When testing Ionic or Angular app you might need to set CORS policy to access a service on a different domain. One way to do this in PHP for testing is to send OK responses for all OPTIONS requests. (If you are testing POST and GET requests)

In your php file set: 

// change to your app origin
header('Access-Control-Allow-Origin: http://localhost:8100');
header ("Access-Control-Expose-Headers: Content-Length, X-JSON");
header ("Access-Control-Allow-Methods: GET, POST, PATCH, PUT, DELETE, OPTIONS");
header ("Access-Control-Allow-Headers: Content-Type, Authorization, Accept, Accept-Language, X-Authorization");
header('Access-Control-Max-Age: 86400');

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    // The request is using the POST method
    header("HTTP/1.1 200 OK");
    return;

}

Don’t ship this test code, this is just for your internal testing of http requests.

How to mask and unmask input element password type in Ionic / Angluar

How to mask and unmask input element password type in ionic/angular/js:

  
this.togglePasswordField = function () {
     console.log("toggle password field called");
     if (document.getElementById("passwordElement").type == "password") {
        document.getElementById("passwordElement").type = "text";

         document.getElementById("passwordHideIcon").classList.remove("ion-eye");
         document.getElementById("passwordHideIcon").classList.add("ion-eye-disabled");
     }
     else {
          document.getElementById("passwordElement").type = "password";
          document.getElementById("passwordHideIcon").classList.remove("ion-eye-disabled");
          document.getElementById("passwordHideIcon").classList.add("ion-eye");     
          }
    }

This way only uses basic html element manipulation.

passwordHideIcon element is a button that calls the function and uses the ionic icon for eyes and eyes disabled.

How to Disable Android Back Button in Ionic 1 / Angular

To disable back button in Android put one of the codes below in your app.js in the .run function.

// app.js

// Disable Back in Entire App
$ionicPlatform.registerBackButtonAction(function(){
  event.preventDefault();
}, 100);

Or Conditionally Disable Back:

// app.js

$ionicPlatform.registerBackButtonAction(function(){
  if($ionicHistory.currentStateName === 'someStateName'){
    event.preventDefault();
  }else{
    $ionicHistory.goBack();
  }
}, 100);