Gearóid's Dev Blog

Update (February 15th, 2016): I have updated the hook with an improved version which prevents issues on a machine where the Android platform has not been added.

Recently I came across a problem where an updated version of Cordova (5.0) added the ACCESS_WIFI_STATE permission to C25K Trainer. Digging into the Cordova git history, I found that this was added to support Crosswalk, used to embed an entire instance of Webkit with your app. Shortly after uploading C25K Trainer with this new update, a user emailed asking about this new permission. I always try to be up front about what information my apps access, so it started to annoy me that users were being asked to accept this permission for no reason.

A friend of mine recently faced the same issue when using a social sharing plugin. One of its features is to share images, which means it requires access to the device’s storage. However, if your app does not use the image sharing feature, it is annoying to have this permission added to your app for no reason.

Permissions for Android apps are defined in the app’s AndroidManifest.xml. This is automatically generated by Cordova based on what you have defined in your config.xml file, as well as the config files of all your plugins. When the app is built, the contents of this file are read and the app’s permissions are set accordingly. So, if we want to remove a permission, we simply remove it from this file. The file we are interested in will be located at platforms/android/AndroidManifest.xml. As this is automatically generated, editing it manually is no good – we need a way to automate permission removal.

Cordova Hooks

Cordova allows you to automatically run scripts before or after most Cordova-related commands – these are called hooks, You can find a full list of all possible hooks here, but the most common tend to be before and after build. To make hooks work, create a folder named hooks in the base of your app. Inside here you can create a folder for each type of hook e.g. a folder named before_build. Inside each of these folders, you can have as many scripts as you want, named whatever you want. It is best practice to write these scripts in node.js so that they can be used cross-platform.

For removing permissions I use the after_prepare hook. You may not be familiar with the Cordova prepare command as it is rarely used by itself. However, when you run cordova build, what this actually does is run cordova prepare followed by cordova compile. Since the prepare command can cause the manifest file to be changed, I remove the permissions after this process is done.

The Code

The result is the following code. Add the permissions you want to remove to the PERMISSIONS_TO_REMOVE array. You should not need to edit anything else. It’s important to only remove permissions that you are sure your app won’t need. If you remove a permission that it does need, your app will crash when it tries to do something that requires that permission.

hooks/after_prepare/remove-permissions.js

#!/usr/bin/env node
var fs = require('fs');

if(fs.existsSync('platforms/android')) {
    const PERMISSIONS_TO_REMOVE = ['ACCESS_WIFI_STATE'],
        MANIFEST = 'platforms/android/AndroidManifest.xml';

        manifestLines = fs.readFileSync(MANIFEST).toString().split('\n'),
        newManifestLines = [];

    const permissions_regex = PERMISSIONS_TO_REMOVE.join('|');

    manifestLines.forEach(function(line) {
        if(!line.match(permissions_regex)) {
            newManifestLines.push(line);
        }
    });

    fs.writeFileSync(MANIFEST, newManifestLines.join('\n'));
}

This file can be named whatever you want, so it’s best to give it a descriptive name. After saving this file, if you are running Linux or OSX, you will need to make the file executable. Do this by running chmod +x hooks/after_prepare/remove-permissions.js.

Now run cordova build and check platforms/android/AndroidManifest.xml to confirm the permission has been removed. That’s it! You’ll never need to worry about removing that permission again as it will always be removed before your project is built.

Re-Adding Permissions

If you find down the line that you now need a permission that you had previously removed, then edit the script above so that it no longer removes the permission you need. To re-add the permission, run cordova platform remove android followed by cordova platform add android. As of Cordova 5.0, this is the only consistent way to ensure that the permissions get added. Though this is slightly annoying, it should not make a difference to your project, as everything inside the platforms folder should always be auto-generated.

Last updated for Phonegap 3.4.0

Phonegap is a program which provides the framework you need to run HTML-based apps across various mobile platforms. It saves you having to write platform-specific code for the vast majority of cases, and plugins are available in most other cases.

In this post I’ll outline the steps to getting a basic app running on Android. It assumes some familiarity with the command line, though I’ll try to explain as much as possible along the way, so don’t be afraid to jump in.

Before I begin, it is worth taking time to clear up any confusion between Cordova and Phonegap. Cordova and Phonegap are almost interchangeable as terms. Phonegap has integration with an online build system called Phonegap Build, but not necessary. I prefer to use Cordova as it has given me fewer issues in the past!

Before we begin

To make things easier, create a folder somewhere and name it “development”. Place any files related to this tutorial there, and also run commands here unless otherwise specified.

Install npm

To make the following steps a lot easier, we need to install npm (Node Package Manager). Install node from http://nodejs.org/download/, which will also install npm for you.

Install Phonegap

Open up the command line / terminal and run the following command to install Phonegap.

npm install -g phonegap

On Mac and Linux you may need to put “sudo” in front of this to run the command with administrator privileges.

Create a new project

phonegap create foldername me.gearoid.test AppName

This will create a new app in “foldername”. Its identifier will be me.gearoid.test. This is a standard way of naming apps — your domain name in reverse with the app name after it. You can name it whatever you want though. It is important to note that this must be unique. You won’t be able to upload your app to app stores if another app exists with the same identifier. Finally AppName is the name of the App that will be displayed in menus, but this can be changed later.

Install Android SDK and ant

Download the Android SDK ADT (Android Developer Tools) Bundle from https://developer.android.com/sdk/index.html and extract this to the “development” folder mentioned earlier.

You will also need to install ant, which is used to build projects.

npm install -g ant

Now you must add a few folders to your PATH. This is where your computer checks for files when you type in programs to execute on the command line. The reason we need to do this is so that typing “android” will run the Android development software, so Phonegap can make the appropriate Android code.

__ ADD PATH INSTRUCTIONS HERE __

Add Android to project

Now that we have all the files needed to make an Android app, we need to tell Phonegap that this project is going to be used on android. On the command line, go to the foldername folder.

phonegap platform add android

Plugins

You can use your app now, but it won’t do very much at all because Phonegap does very little by itself. To achieve anything you will need to add plugins. This is new for Phonegap 3. Older versions had a lot of this automatically built in. Below is how you install the most basic plugin. A full list is available at http://docs.phonegap.com/en/3.4.0/guide_cli_index.md.html#The%20Command-Line%20Interface_add_plugin_features

phonegap local plugin add org.apache.cordova.device

If you are using Cordova, leave out the “local” above. This relates to Phonegap Build, which is not supported by Cordova.