Develop Reference

Generated code stays in build folder after Android Studio Build

I am using a gradle task to generate some code for my API and store this code into the build folder. When I am building my application the process deletes the build folder.
Is there a way to call my code generation task between the folder deletion and the start of the compilation?

I am not a Gradle expert, so their might be better answers!
In your build.gradle you can create custom tasks and make them depend on other tasks:
// this is your new task
task generateCode() {
description 'Generates some code...'
doLast {
println("generateCode")
// do your code generation here
}
}
// put the name of the task you wanna depend on, like: compileSources
project.task("compileSources").dependsOn generateCode
When you call this task ./gradlew compileSources you should see that the custom task generateCode gets executed first.

After allot of trying , i found the solution .
In the build.gradle i had to add the preBuild.finalizedBy(generateCode)

Gradle task for Sentry not compiling

I have to add the Analytics tool Sentry to our Android project. In order to make it work, one needs to create mappings for the obfuscated code (from Proguard/R8) and upload it later to Sentry.
On the website https://docs.sentry.io/platforms/android/ it is even described how to do that.
There it is written that one needs to create a gradle task looking like this:
gradle.projectsEvaluated {
android.applicationVariants.each { variant ->
def variantName = variant.name.capitalize();
def proguardTask = project.tasks.findByName(
"transformClassesAndResourcesWithProguardFor${variantName}")
def dexTask = project.tasks.findByName(
"transformClassesWithDexFor${variantName}")
def task = project.tasks.create(
name: "processSentryProguardFor${variantName}",
type: Exec) {
workingDir project.rootDir
commandLine *[
"sentry-cli",
"upload-proguard",
"--write-properties",
"${project.rootDir.toPath()}/app/build/intermediates/assets" +
"/${variant.dirName}/sentry-debug-meta.properties",
variant.getMappingFile(),
"--no-upload"
]
}
dexTask.dependsOn task
task.dependsOn proguardTask
}
}
This shall wait until Proguard is finished, than copy this properties file to the assets. However, when I add this to my Android gradle script I get the error:
Could not create task
':app:processSentryProguardForPlayStoreStagingDebug'.
No signature of method: java.util.ArrayList.multiply() is applicable for argument types: (ArrayList) values: [[sentry-cli, upload-proguard,
--write-properties, {Application-Path}/app/build/intermediates/assets/playStoreStaging/debug/sentry-debug-meta.properties,
...]] Possible solutions: multiply(java.lang.Number),
multiply(java.lang.Number)
I assume there is something wrong with the multiplication symbol * before the commandLine array. But when I remove it I get the error
Could not create task
':app:processSentryProguardForPlayStoreStagingDebug'.
Cannot cast object 'sentry-cli' with class 'java.lang.String' to class 'int'
So I tried to test this with only that line
commandLine "sentry-cli", ...
Which gave me another error
What went wrong: Cannot invoke method dependsOn() on null object
Thus I assume something went really wrong with that gradle script since it seems the dependend task can't be found. Does anyone have any idea how to fix this (or optionally have any other idea how to copy that sentry-debug-meta.properties file to my assets in another way, once Proguard/R8 is finished)?
Thanks!
-------- EDIT --------
I noticed something important.
The gradle tasks are defined in a different name than what was defined in the manual. Looking at my tasks I have them named
transformClassesAndResourcesWithR8For...
and
transformClassesWithDexBuilderFor...
However, I print the variantName then for checking but it seems my tasks are incomplete.
In my tasks list there exist
transformClassesAndResourcesWithR8ForPlayStoreStagingDebug
but not
transformClassesAndResourcesWithR8ForPlayStoreStagingRelease
and thus the task can't be found. I think that is the real problem here. So where are these gradle tasks defined?
------- EDIT 2 --------
Okay I noticed something strange here. Some variants don't have tasks. It makes sense that DEBUG tasks don't have R8 tasks but I found this here:
Variant: PlayStoreStagingRelease DexTask is null
Variant: PlayStorePreviewRelease DexTask is null
Variant: HockeyAppRelease DexTask is null
Variant: LocalServerRelease DexTask is null
Variant: PlayStoreProductionRelease DexTask is null
So how can this be?

I'd recommend using the Sentry Gradle integration (Gradle plugin) which is described here https://docs.sentry.io/platforms/android/#gradle-integration
The official Android Gradle plugin changed its task names over versions, Gradle version also affects those code snippets.
Google also replaced Proguard with R8 and it also affected those code snippets.
Is there a reason why not using the Sentry Gradle integration? if so, We'll be looking into updating them.
Thanks.

java.util.ArrayList.multiply() hints for that * in front of the [ ] list, which looks strange to me. Try removing the *[ ], only keeping List<String> (there's no ArrayList expected, to begin with):
commandLine "sentry-cli", "upload-proguard", "--write-properties", "${project.rootDir.toPath()}/app/build/intermediates/assets/${variant.dirName}/sentry-debug-meta.properties", variant.getMappingFile(), "--no-upload"
You'd have to look up how your tasks are actually being called, but it should be something alike:
def r8Task = project.tasks.findByName("transformClassesAndResourcesWithR8For${variantName}")
def d8Task = project.tasks.findByName("transformClassesWithDexBuilderFor${variantName}")
With a null check, because not every variant might have minifyEnabled true set:
if(r8Task != null) {
d8Task.dependsOn task
task.dependsOn r8Task
}
Maybe even a previous null check is required, because variant.getMappingFile() needs R8.
And that some flavors have no D8 task might be based upon the absence of code (nothing to do).

Here's a summary of the steps that I followed for integrating Sentry with my Android app. These steps are to ensure the sentry gradle plugin works as expected and automatically uploads the proguard mapping files, without you having to worry about uploading using cli. I assume you would have setup the Sentry SDK as described here:
https://docs.sentry.io/platforms/android/#integrating-the-sdk
Ensure you have Android Studio gradle plugin 3.5.0 (Not 3.6.x, that seems to break the sentry plugin. I observed that the sentry proguard or native symbol upload tasks are not configured or executed at all). This value should be in your root project's build.gradle in dependencies block
Provide a sentry.properties file the root folder of your project. The sentry.properties file should have the following values at minimum:
defaults.project=your_sentry_project_name
defaults.org=your_sentry_org_name
auth.token=sentry_project_auth_token
You can get info about generating auth tokens here: https://sentry.io/settings/account/api/auth-tokens/
(Optional: If you have build flavors) In my case, I have different flavors for my app. So, I had to put the sentry.properties inside my flavor specific folder in /app/src/ folder. Then, I wrote a gradle task to copy the flavor specific sentry.properties file into the project's root folder during gradle's configuration phase. Example:
task copySentryPropertiesTask {
if (getBuildFlavor() != null && !getBuildFlavor().isEmpty()) {
println("Copying Sentry properties file: ${getBuildFlavor()}")
copy {
from "src/${getBuildFlavor()}/"
include "sentry.properties"
into "../"
}
}
}
def getBuildFlavor() {
Gradle gradle = getGradle()
String tskReqStr = gradle.getStartParameter().getTaskRequests().toString()
Pattern pattern;
if (tskReqStr.contains("assemble"))
pattern = Pattern.compile("assemble(\\w+)(Release|Debug)")
else
pattern = Pattern.compile("generate(\\w+)(Release|Debug)")
Matcher matcher = pattern.matcher(tskReqStr)
if (matcher.find())
return matcher.group(1)
else {
println "NO MATCH FOUND"
return ""
}
}
Note 1: You can place this task in your app/build.gradle anywhere (I had placed it at the end).
Note 2: If you followed step 3 for build flavors, you can also add the root folder's sentry.properties in .gitignore. Since, it will be copied everytime you create a build.
Sentry should now be able to upload the proguard files for any release builds (or if you set minifyEnabled=true for any buildType).

Copy only certain assets to APK based on gradle flavors

I have an Android Studio project which uses NDK and CMake and externalNativeBuild. To reduce packet size I have several flavors for different texture compression formats. There are no code changes, i.e. all the resulting APKs are using exactly the same code.
productFlavors {
ETC2 {
manifestPlaceholders = [supportedTexture: "GL_OES_compressed_ETC2_RGB8_texture"]
}
DXT {
manifestPlaceholders = [supportedTexture: "GL_EXT_texture_compression_dxt1"]
}
ATC {
manifestPlaceholders = [supportedTexture: "GL_AMD_compressed_ATC_texture"]
}
//...and list goes on...
}
What this means in practice is that I have a Copy task which checks the current flavor and copies the correct texture pack into the APK. The getCurrentFlavor() function is copied from How to get current flavor in gradle:
task copyTexSD(type: Copy) {
def currentFlavor = getCurrentFlavor()
if(currentFlavor == "etc2") {
from 'bin/tex/ETC2.bin'
}
else if(currentFlavor == "dxt") {
from 'bin/tex/DXT.bin'
}
else if(currentFlavor == "atc") {
from 'bin/tex/ATC.bin'
}
//...
into 'src/main/assets/tex'
}
To build averything I use the following batch command:
call gradlew clean
call gradlew assembleETC2Release
call gradlew assembleDXTRelease
call gradlew assembleATCRelease
This works otherwise well, but for some reason the texture packets which are copied to previous APKs are also included in the subsequent APKs like this:
app-ETC2-release.apk contains only ETC2.bin file
app-DXT-release.apk contains DXT.bin and ETC2.bin
app-ATC-release.apk contains ATC.bin, DXT.bin and ETC2.bin
Why the build process includes assets from previous Gradle task? How can I make the build process to have only one texture file per APK?

Somehow I had a wrong assumption that each gradle task would be independent. Of course all the file(s) that have been copied in the assets folder in previous tasks are still there if they are not explicitly deleted.
So, there seems to be two possibilities to get this to work:
1) Modify the batch file to delete data from the texture folder before calling next gradle task.
OR
2) Create delete task in gradle file which runs before copy task. Examples can be found here: Gradle - Delete files with certain extension .

gradle copy as doLast not working

I am trying to do a very simple thing. As gradle removes all files in the build dir when cleaning I want to move the apks somewhere else when creating release versions. So I added a copy task into the chain and I set it to be the last. Anything I tried did't work. So I simplified it and added some logging to make a point. I think it just doesn't work.
Using two variables, I can check that at task definition time and execution time the input and output paths are valid. I can also check that the task is executed. I put some more files in the input directory to make sure there is also something there in any case. This is the script:
def buildPath
def outPath
task copyApks(type: Copy) {
buildPath = "$buildDir\\outputs\\apk"
outPath ="$buildDir\\outputs\\apk2"
logger.error("Source Folder is $buildPath")
logger.error("Destination Folder is $outPath")
from buildPath
into outPath
}
assembleRelease.doLast {
android.applicationVariants.all { variant ->
println "Variant $variant.name"
logger.error("Source Folder is $buildPath")
logger.error("Destination Folder is $outPath")
copyApks
}
}
And this is the output, where one can see that the paths are correct (they exist and are valid) both at definition and execution time. Also one can see that the task is executed:
What is wrong?
Executing external task 'assembleRelease'...
Parallel execution with configuration on demand is an incubating feature.
Source Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk
Destination Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk2
................
some other gradle logs
................
:app:assembleRelease
Variant debug
Source Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk
Destination Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk2
Variant release
Source Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk
Destination Folder is C:\Users\Administrator\Projects\Gradle\MB6\app\build\outputs\apk2
BUILD SUCCESSFUL

First of all, you have to know, that just adding the task name into your closure, in your case it's copyApks, doesn't really mean that this task should be executed. It's just the same, as you specified a variable, but do nothing with it.
And one more, note, the both variants paths are the same, that means that you are trying to copy tha same files twice. Actually, that not the only reason, you have to understand, that your copy task is configured yet in the configuration phase, when you are trying to call it during the execution phase, so you can't change it's from and into parameters, and this task will always behave the same.
If you want to call some tasks one after another, you have a number of choices, like task dependencies, task finalization or task ordering. You can read about it in the official user guide. There is a way to call some task like a method call, but this is a very poor solution and you have to avoid using it.
So, if you want to call a copy task, then you may try solution like this
assembleRelease.finalizedBy copyApks
This will call a copy task always every time assembling is done.

Custom Class Loading in Dalvik with Gradle (Android New Build System)

As per the introduction of Custom Class Loading in Dalvik by Fred Chung on the Android Developers Blog:
The Dalvik VM provides facilities for developers to perform custom
class loading. Instead of loading Dalvik executable (“dex”) files from
the default location, an application can load them from alternative
locations such as internal storage or over the network.
However, not many developers have the need to do custom class loading. But those who do and follow the instructions on that blog post, might have some problems mimicking the same behavior with Gradle, the new build system for Android introduced in Google I/O 2013.
How exactly one can adapt the new build system to perform the same intermediary steps as in the old (Ant based) build system?

My team and I recently reached the 64K method references in our app, which is the maximum number of supported in a dex file. To get around this limitation, we need to partition part of the program into multiple secondary dex files, and load them at runtime.
We followed the blog post mentioned in the question for the old, Ant based, build system and everything was working just fine. But we recently felt the need to move to the new build system, based on Gradle.
This answer does not intend to replace the full blog post with a complete example. Instead, it will simply explain how to use Gradle to tweak the build process and achieve the same thing. Please note that this is probably just one way of doing it and how we are currently doing it in our team. It doesn't necessarily mean it's the only way.
Our project is structured a little different and this example works as an individual Java project that will compile all the source code into .class files, assemble them into a single .dex file and to finish, package that single .dex file into a .jar file.
Let's start...
In the root build.gradle we have the following piece of code to define some defaults:
ext.androidSdkDir = System.env.ANDROID_HOME
if(androidSdkDir == null) {
Properties localProps = new Properties()
localProps.load(new FileInputStream(file('local.properties')))
ext.androidSdkDir = localProps['sdk.dir']
}
ext.buildToolsVersion = '18.0.1'
ext.compileSdkVersion = 18
We need the code above because although the example is an individual Java project, we still need to use components from the Android SDK. And we will also be needing some of the other properties later on... So, on the build.gradle of the main project, we have this dependency:
dependencies {
compile files("${androidSdkDir}/platforms/android-${compileSdkVersion}/android.jar")
}
We are also simplifying the source sets of this project, which might not be necessary for your project:
sourceSets {
main {
java.srcDirs = ['src']
}
}
Next, we change the default configuration of the build-in jar task to simply include the classes.dex file instead of all .class files:
configure(jar) {
include 'classes.dex'
}
Now we need to have new task that will actually assemble all .class files into a single .dex file. In our case, we also need to include the Protobuf library JAR into the .dex file. So I'm including that in the example here:
task dexClasses << {
String protobufJarPath = ''
String cmdExt = Os.isFamily(Os.FAMILY_WINDOWS) ? '.bat' : ''
configurations.compile.files.find {
if(it.name.startsWith('protobuf-java')) {
protobufJarPath = it.path
}
}
exec {
commandLine "${androidSdkDir}/build-tools/${buildToolsVersion}/dx${cmdExt}", '--dex',
"--output=${buildDir}/classes/main/classes.dex",
"${buildDir}/classes/main", "${protobufJarPath}"
}
}
Also, make sure you have the following import somewhere (usually at the top, of course) on your build.gradle file:
import org.apache.tools.ant.taskdefs.condition.Os
Now we must make the jar task depend on our dexClasses task, to make sure that our task is executed before the final .jar file is assembled. We do that with a simple line of code:
jar.dependsOn(dexClasses)
And we're done... Simply invoke Gradle with the usual assemble task and your final .jar file, ${buildDir}/libs/${archivesBaseName}.jar will contain a single classes.dex file (besides the MANIFEST.MF file). Just copy that into your app assets folder (you can always automate that with Gradle as we've done but that is out of scope of this question) and follow the rest of the blog post.
If you have any questions, just shout in the comments. I'll try to help to the best of my abilities.

The Android Studio Gradle plugin now provides native multidex support, which effectively solves the Android 65k method limit without having to manually load classes from a jar file, and thus makes Fred Chung's blog obsolete for that purpose. However, loading custom classes from a jar file at runtime in Android is still useful for the purpose of extensibility (e.g. making a plugin framework for your app), so I'll address that usage scenario below:
I have created a port of the original example app on Fred Chung's blog to Android Studio on my github page over here using the Android library plugin rather than the Java plugin. Instead of trying to modify the existing dex process to split up into two modules like in the blog, I've put the code which we want to go into the jar file into its own module, and added a custom task assembleExternalJar which dexes the necessary class files after the main assemble task has finished.
Here is relevant part of the build.gradle file for the library. If your library module has any dependencies which are not in the main project then you will probably need to modify this script to add them.
apply plugin: 'com.android.library'
// ... see github project for the full build.gradle file
// Define some tasks which are used in the build process
task copyClasses(type: Copy) { // Copy the assembled *.class files for only the current namespace into a new directory
// get directory for current namespace (PLUGIN_NAMESPACE = 'com.example.toastlib')
def namespacePath = PLUGIN_NAMESPACE.replaceAll("\\.","/")
// set source and destination directories
from "build/intermediates/classes/release/${namespacePath}/"
into "build/intermediates/dex/${namespacePath}/"
// exclude classes which don't have a corresponding .java entry in the source directory
def remExt = { name -> name.lastIndexOf('.').with {it != -1 ? name[0..<it] : name} }
eachFile {details ->
def thisFile = new File("${projectDir}/src/main/java/${namespacePath}/", remExt(details.name)+".java")
if (!(thisFile.exists())) {
details.exclude()
}
}
}
task assembleExternalJar << {
// Get the location of the Android SDK
ext.androidSdkDir = System.env.ANDROID_HOME
if(androidSdkDir == null) {
Properties localProps = new Properties()
localProps.load(new FileInputStream(file('local.properties')))
ext.androidSdkDir = localProps['sdk.dir']
}
// Make sure no existing jar file exists as this will cause dx to fail
new File("${buildDir}/intermediates/dex/${PLUGIN_NAMESPACE}.jar").delete();
// Use command line dx utility to convert *.class files into classes.dex inside jar archive
String cmdExt = Os.isFamily(Os.FAMILY_WINDOWS) ? '.bat' : ''
exec {
commandLine "${androidSdkDir}/build-tools/${BUILD_TOOLS_VERSION}/dx${cmdExt}", '--dex',
"--output=${buildDir}/intermediates/dex/${PLUGIN_NAMESPACE}.jar",
"${buildDir}/intermediates/dex/"
}
copyJarToOutputs.execute()
}
task copyJarToOutputs(type: Copy) {
// Copy the built jar archive to the outputs folder
from 'build/intermediates/dex/'
into 'build/outputs/'
include '*.jar'
}
// Set the dependencies of the build tasks so that assembleExternalJar does a complete build
copyClasses.dependsOn(assemble)
assembleExternalJar.dependsOn(copyClasses)
For more detailed information see the full source code for the sample app on my github.

See my answer over here. The key points are:
Use the additionalParameters property on the dynamically created dexCamelCase tasks to pass --multi-dex to dx and create multiple dex files.
Use the multidex class loader to use the multiple dex files.