Automating Builds on Android - Part 2

In the previous post, Automating Builds on Android - Part 1, we saw how to setup our projects to automate the build process. In this post, we will automate the process further to make Ant automatically use the passwords for our keystore and alias, label our builds to whatever name we like and put it in a specific location on your system (from where others can access it).

1. To make Ant use the passwords for our keystore automatically, we will create a separate properties file in our project folder where. Let's name it "passwords.properties". This file would contain two properties as listed below.

key.store.password=sample
key.alias.password=sample

2. We will need to make a small change in our build.xml file to tell Ant to load this property file while building. To do this, we simply add this one line in the build.xml file.

<property file="passwords.properties" />

If you try to run "ant release" command in your terminal, you will notice that Ant doesn't ask you to enter your passwords anymore. It has picked up the passwords from your passwords.properties file.

3. Adding a name and a time-stamp to your builds while making a release build needs a little more effort. We will now create another properties file called "extras.properties". This file would contain two more properties as listed below.

file_name_format=test_build_hello_world

build_location=C:/Builds/HelloWorld

The file_name_format would be used to name your output builds. Sometimes, you would want to name your builds differently based on whether it is a "daily_build" or "weekly_build" or a "release_build". Instead of renaming the output file manually, you could just change this property accordingly just before your type in "ant release", and your builds would automatically be named as you like. The other property, build_location is again a configurable value here, where Ant would put all your builds in the specified location. This could be a shared folder on your system from where anyone else can access it easily.

4. Now comes the lengthy part. To accommodate these changes in our build process, our original build.xml is not enough. We will have to tweak the actual underlying build.xml to make our build process more streamlined. Let's see how to do it. Pick up the build.xml from the sample project and replace the previous build.xml with this one. It will have a whole lot of Ant scripts. You don't have to worry about most of it, except for these lines.

    <!-- Date/Time format for naming the file-->
    <tstamp>
        <format property="time" pattern="dd_MMM" />
    </tstamp>
    <property file="local.properties" />
    <property file="passwords.properties" />
    <property file="extras.properties" />

Notice, that, we are using a time-stamp property which we would be using in our build.xml to version our builds based on the specific format. Our builds will be names as "test_build_hello_world_22_SEP.apk".

The last thing you need to change is this piece of code. You will find it somewhere in the new build.xml.

    <property name="out.release.file.name" value="${file_name_format}_${time}.apk" />
    <property name="out.release.file" location="${build_location}/${out.release.file.name}" />

5. Here, you can see that we have changed the property "out.release.file.name" to a value that we want the output file to be named as. And also, we changed the "out.release.file" to use our configured directory from the extras.properties file.

The final step is to run "ant release" for the last time, and you will see your final release build placed at your desired location.

You can find the sample project here.

Automating Builds on Android - Part 1

Do you find it hard to get a release build of an Android app? Well, you could say that it's not at all difficult. It just takes about 1 minute to get a build, sign it with your release keys and you are done. For a typical moderately big Android app, you could have a QA process where you send out builds for testing or verification to someone else. And you could be sending out the builds multiple times a day. In such situations, it becomes a tad tedious getting release builds out of your eclipse. In this post, we will try to automate this process of preparing the release builds.

Our tool of choice is Ant. Most of you perhaps already know how to do set it up. We will, however, also see how to version or auto-label your builds in next post. In this post, we will go through the basics.

1. To start off with, create a "HelloWorldAnt" Android project.

2. The next step is to prepare our project to use Ant scripts. To do this, fire up your terminal, go to the directory where your project rests and type out this command.

android update project -p .

3. A few files would be added to your project. Among these, the build.xml is the file that Ant would read and package your apk.

Updated local.properties

Added file ./build.xml

Updated file ./proguard.cfg

4. Now try running this command in the terminal. After we setup everything, this is the one single command that we would run every time we need to create a release build.

ant release

5. You will see a long log of what Ant is doing. Look towards the end of the logs and you will notice these lines:

-release-nosign:

     [echo] No key.store and key.alias properties found in build.properties.

     [echo] Please sign /workspace/HelloWorldAnt/bin/HelloWorldAntActivity-unsigned.apk manually

     [echo] and run zipalign from the Android SDK tools.

6. So, till this point, the Ant tool has prepared an unsigned apk which it has kept in the bin folder of your project and it asks you to manually sign this apk with your release keys. Next step is to automate this process.

7. Put your keystore inside your project folder. For this project, sample_keystore is the keystore that we would be using to sign this application. Now, we need to tell Ant to use this keystore to sign our builds with. Here, we will add a few files to our project.

Filename: build.properties

File Listing:

key.store=sample_keystore
key.alias=samplekeystore

 8. At this point, if you try running "ant release" command, it will ask you to enter the password for the keystore and the alias name, and finally, it would put the release and signed builds in your bin folder. 

The next post will talk about customizing the build process to the next level.

Automating Builds on Android - Part 2

You can find the sample project here.

Sign your Android applications for release

The process of application signing can be very confusing for new developers. But, once you have done it 2-3 times, it will be more like a chore for you after that. It's not very complicated at all. So, here are the steps that you need to follow.

Note: If you already have a self-signed certificate/keystore, skip to step 2(b):

Step 1: Right click on the Android project. From the context menu, select, Android Tools -> Export Signed application package. In the dialog that will open, you will see the name of your project. If you have selected the wrong project, here is a chance to correct yourself. Click on "Next".

 

Step 2:  The next screen is the most complicated screen that you will get in this process. Here, you can have two situations.

a. If you don't have a keystore already, you will need to create one first. Once created, you should preserve this keystore somewhere, safely, so that you don't accidentally delete it. You will need this keystore everytime you want to sign and update your application to the Android Market. Please, please, please, DO NOT LOSE THIS KEYSTORE.

                                       

Since, we are creating a new keystore this time, select the second radio, and browse to a location where you want you new keystore to be saved. Enter and confirm a password. Remember this password. Click on "Next".

Enter all the fields in this screen and press enter. Now your keystore will be created. Please rememeber all your passwords. Else, this keystore will be useless for you later.For simplicity, keep both the passwords same.

On this screen, specify a name and location of the apk and click on "Finish". Your signed application package will be created for you in the location you have mentioned here. You can now take this apk and directly upload it to the Android market, or put it on your phone.

b. When you already have a kestore, it's more easier to sign your application. On the second screen, select, "Use existing keystore". Enter the location of the keystore and password. Click on "Next". On the next screen, select you alias from the drop down, enter the alias password, click on "Next". On the next screen, specify a name and location where you want the apk to be created and click "Finish". You are done now.

Isn't it simple? Just one point to note: If you are using an old ADT version, this option of signing your apps from eclipse might now be there. In such a case, you will have to do it through command line. You can find many tutorials on how to achieve that.

The official document can be found here: http://developer.android.com/guide/publishing/app-signing.html#signing

Thanks,

Kumar