Read and Write permission for storage and gallery - open failed: EACCES (Permission denied) Cordova

After Android OS upgrade to Marshmallow(6.0), permission has categorized into two sections "Normal and Dangerous Permissions". On this version on wards, users have to grant permission when the app is running but not at the time of app installation via play store. Also app developers have to request permission on "Dangerous Permission" at the time of using device resources such as Camera, Location, Gallery, External Storage.

Normal permissions do not directly risk the user's privacy. If your app lists a normal permission in its manifest, the system grants the permission automatically.

Dangerous permissions can give the app access to the user's confidential data. If your app lists a normal permission in its manifest, the system grants the permission automatically. If you list a dangerous permission, the user has to explicitly give approval to your app.
(Reference: Android API)


Let's create a sample Ionic project using Visual Studio 2015 to see how it is get done beginning of Marshmallow(API Level 23).

Step 01:- Create a Iconic tab template

Step 02:- Install File, FileTransfer, Permission plugins

cordova plugin add cordova-plugin-file
cordova plugin add cordova-plugin-file-transfer
cordova plugin add cordova-plugin-android-permissions@0.10.0

Please refer more details for the API urls listed below:

• file (https://github.com/apache/cordova-plugin-file)
• file-transfer (https://github.com/apache/cordova-plugin-file-transfer)
• permissions (https://github.com/NeoLSN/cordova-plugin-android-permission)

Step 03:- Add a button to your UI and create a method in your control.

angular.module('starter.controllers', ['ionic'])

.controller('DashCtrl', function ($scope, $ionicPlatform) {

    $scope.downloadFile = function () {

        $ionicPlatform.ready(function () {
       // File for download
       var url = "http://www.gajotres.net/wp-content/uploads/2015/04/logo_radni.png";

       // File name only
       var filename = url.split("/").pop();

       // Save location
        var targetPath = cordova.file.externalRootDirectory + 'Download/' + filename;

       var fileTransfer = new FileTransfer();
       var uri = encodeURI(url);
       var trustHosts = true
       var options = {};


            fileTransfer.download(
                uri,
                targetPath,
                function (entry) {
                    console.log("download complete: " + entry.toURL());
                },
                function (error) {
                    console.log("download error source " + error.source);
                    console.log("download error target " + error.target);
                    console.log("download error code" + error.code);
                },
                trustHosts,
                options
            );
        });
    };
})

If you run this code without requesting permission for external storage, it will throw  open failed: EACCES (Permission denied) error message.

Step 04:-  Let's modify the code to request permission for storage.

Note: Go through the API documentation for more details.

//var permissions = cordova.plugins.permissions;
//permissions.hasPermission(permission, successCallback, errorCallback);
//permissions.requestPermission(permission, successCallback, errorCallback);
//permissions.requestPermissions(permissions, successCallback, errorCallback);


var permissions = cordova.plugins.permissions;
permissions.hasPermission(permissions.READ_EXTERNAL_STORAGE, checkPermissionCallback, null);

        function checkPermissionCallback(status) {
            if (!status.hasPermission) {
                var errorCallback = function () {
                    console.warn('Storage permission is not turned on');
                }
                permissions.requestPermission(
                  permissions.READ_EXTERNAL_STORAGE,
                  function (status) {
                      if (!status.hasPermission) {
                          errorCallback();
                      } else {
                          // continue with downloading/ Accessing operation 
                          $scope.downloadFile();
                      }
                  },
                  errorCallback);
            }
        }

Deferred long-running timer task(s) to improve scrolling smoothness : IONIC

I recently encountered this warring message during the ionic application deployment. In the application console
Deferred long-running timer task(s) to improve scrolling smoothness warring message was keep popping out. After an investigation I found that error was throwing due
$timeout service in angular.


$scope.searchTimer = $timeout(function () { 
    $scope.initiateSearch(true); 
 }, 500); //wait .5 seconds after the user finished typing.

The reason was I was doing a task using a timer. To get rid of this warning message, I had to destroy it after using it. Therefore I used $destroy event to kill the timer.

$scope.$on( 
   "$destroy", 
    function( event ) { 
    $timeout.cancel( timer ); 
 });