How to generate OpenAPI sources from gradle when building Android app - android

What I'm trying to achieve
I'm trying to generate my REST API client for Android using OpenAPI Generator from the build.gradle script. That way, I wouldn't have to run the generator command line every time the specs change. Ideally, this would be generated when I build/assemble my app, and the sources would end up in the java (generated) folder, where generated sources are then accessible from the code (this is what happens with the BuildConfig.java file for example).
What I've tried so far
Following this link from their official GitHub, here's the build.gradle file I ended up with:
apply plugin: 'com.android.application'
apply plugin: 'org.openapi.generator'
...
openApiValidate {
inputSpec = "$rootDir/app/src/main/openapi/my-api.yaml"
recommend = true
}
openApiGenerate {
generatorName = "java"
inputSpec = "$rootDir/app/src/main/openapi/my-api.yaml"
outputDir = "$buildDir/generated/openapi"
groupId = "$project.group"
id = "$project.name-openapi"
version = "$project.version"
apiPackage = "com.example.mypackage.api"
invokerPackage = "com.example.mypackage.invoker"
modelPackage = "com.example.mypackage.model"
configOptions = [
java8 : "true",
dateLibrary : "java8",
library : "retrofit2"
]
}
...
First, I've never managed to get the API generated with the build/assemble task, even when I tried adding:
compileJava.dependsOn tasks.openApiGenerate
or
assemble.dependsOn tasks.openApiGenerate
The only way I could generate the sources was by manually triggering the openApiGenerate task:
Then, when I do generate my sources this way, they end up in the build folder but aren't accessible from my code, and aren't visible in the java (generated) folder:
I then have to manually copy/paste the generated source files to my project sources in order to use the API.
Even though I'm able to work around these issues by adding manual procedures, it would be way more maintainable if the whole process was simply automatic. I was able to achieve a similar result with another tool, Protobuf. Indeed, my gradle task gets triggered every time I build the app, and the sources end up in the java (generated) folder, so I don't have to do any additional work. The task is much simpler though, so I assume the main work that I'm not able to replicate with OpenAPI Generator is handled by the Protobuf plugin itself.

You have to specify path to the generated sources as a custom source set for your Gradle module, which is app in this case, as described here – https://developer.android.com/studio/build/build-variants#configure-sourcesets. That way Gradle will treat your sources as accessible from your code.
Something like this:
android {
...
sourceSets {
main {
java.srcDirs = ['build/generated/openapi/src/main/java']
}
}
...
}

I solved the issue you described like this, I'm using gradle.kts however.
See my build.gradle.kts
plugins {
// Your other plugins
id("org.openapi.generator") version "5.3.0"
}
openApiGenerate {
generatorName.set("kotlin")
inputSpec.set("$rootDir/app/src/main/openapi/my-api.yaml")
outputDir.set("$buildDir/generated/api")
// Your other specification
}
application {
// Your other code
sourceSets {
main {
java {
// TODO: Set this path according to what was generated for you
srcDir("$buildDir/generated/api/src/main/kotlin")
}
}
}
}
tasks.compileKotlin {
dependsOn(tasks.openApiGenerate)
}
You need to build the application at least once for the IDE to detect the library (at least this is the case for me in Intellij)

Your build should automatically generate the open api classes , to refer the generated classes in your java project you should add the generated class path to your source directory like it was mentioned in the other answers
https://developer.android.com/studio/build/build-variants#configure-sourcesets
As far as the task dependency goes , in android tasks are generated after configuration thus for gradle to recognize the task , wrap it inside afterEvaluate block like
afterEvaluate {
tasks.compileDebugJavaWithJavac.dependsOn(tasks.openApiGenerate)
}

I had this issue, and this answer https://stackoverflow.com/a/55646891/14111809 led me to a more informative error:
error: incompatible types: Object cannot be converted to Annotation
#java.lang.Object()
Taking a look at the generated files that were causing this error, noticed:
import com.squareup.moshi.Json;
After including a Moshi in the app build.gradle, the build succeeded and the generated code was accessible.
implementation("com.squareup.moshi:moshi-kotlin:1.13.0")

Related

Is it possible to get dependency version at runtime, including from library itself?

Background
Suppose I make an Android library called "MySdk", and I publish it on Jitpack/Maven.
The user of the SDK would use it by adding just the dependency of :
implementation 'com.github.my-sdk:MySdk:1.0.1'
What I'd like to get is the "1.0.1" part from it, whether I do it from within the Android library itself (can be useful to send to the SDK-server which version is used), or from the app that uses it (can be useful to report about specific issues, including via Crashlytics).
The problem
I can't find any reflection or gradle task to reach it.
What I've tried
Searching about it, if I indeed work on the Android library (that is used as a dependency), all I've found is that I can manage the version myself, via code.
Some said I could use BuildConfig of the package name of the library, but then it means that if I forget to update the code a moment before I publish the dependency, it will use the wrong value. Example of using this method:
plugins {
...
}
final def sdkVersion = "1.0.22"
android {
...
buildTypes {
release {
...
buildConfigField "String", "SDK_VERSION", "\"" + sdkVersion + "\""
}
debug {
buildConfigField "String", "SDK_VERSION", "\"" + sdkVersion + "-unreleased\""
}
}
Usage is just checking the value of BuildConfig.SDK_VERSION (after building).
Another possible solution is perhaps from gradle task inside the Android-library, that would be forced to be launched whenever you build the app that uses this library. However, I've failed to find how do it (found something here)
The question
Is it possible to query the dependency version from within the Android library of the dependency (and from the app that uses it, of course), so that I could use it during runtime?
Something automatic, that won't require me to update it before publishing ?
Maybe using Gradle task that is defined in the library, and forced to be used when building the app that uses the library?
You can use a Gradle task to capture the version of the library as presented in the build.gradle dependencies and store the version information in BuildConfig.java for each build type.
The task below captures the version of the "appcompat" dependency as an example.
dependencies {
implementation 'androidx.appcompat:appcompat:1.4.0'
}
task CaptureLibraryVersion {
def libDef = project.configurations.getByName('implementation').allDependencies.matching {
it.group.equals("androidx.appcompat") && it.name.equals("appcompat")
}
if (libDef.size() > 0) {
android.buildTypes.each {
it.buildConfigField 'String', 'LIB_VERSION', "\"${libDef[0].version}\""
}
}
}
For my example, the "appcompat" version was 1.4.0. After the task is run, BuildConfig.java contains
// Field from build type: debug
public static final String LIB_VERSION = "1.4.0";
You can reference this field in code with BuildConfig.LIB_VERSION. The task can be automatically run during each build cycle.
The simple answer to your question is 'yes' - you can do it. But if you want a simple solution to do it so the answer transforms to 'no' - there is no simple solution.
The libraries are in the classpath of your package, thus the only way to access their info at the runtime would be to record needed information during the compilation time and expose it to your application at the runtime.
There are two major 'correct' ways and you kinda have described them in your question but I will elaborate a bit.
The most correct way and relatively easy way is to expose all those variables as BuildConfig or String res values via gradle pretty much as described here. You can try to generify the approach for this using local-prefs(or helper gradle file) to store versions and use them everywhere it is needed. More info here, here, and here
The second correct, but much more complicated way is to write a gradle plugin or at least some set of tasks for collecting needed values during compile-time and providing an interface(usually via your app assets or res) for your app to access them during runtime. A pretty similar thing is already implemented for google libraries in Google Play services Plugins so it would be a good place to start.
All the other possible implementations are variations of the described two or their combination.
You can create buildSrc folder and manage dependencies in there.
after that, you can import & use Versions class in anywhere of your app.

Android: Add maven-publish configuration in a separate kotlin dsl script

I've written a .gradle script named publish.gradle which configures publishing {} for releasing my artifact.
Why on a separate script? I have multiple modules and by doing this every releasable module simply defines some variables.
Module build.gradle.kts:
// Module's blah blah
apply(from = "../publish.gradle")
publish.gradle:
apply plugin: 'maven-publish'
publishing {
publications {
// configure release process
}
}
I've recently decided to migrate to Gradle Kotlin DSL. However, there's an issue:
Adding publication {} like this:
plugins {
`maven-publish`
}
publication {
}
Lead to this error:
Expression 'publishing' cannot be invoked as a function. The function 'invoke()' is not found
Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
public val PluginDependenciesSpec.publishing: PluginDependencySpec defined in org.gradle.kotlin.ds
Which is summarized to
PluginDependenciesSpec is not present as a receiver
What is the difference?
TL; DR
I've added publishing {} config to a separate script which works when in .gradle groovy format but I can not convert to .gradle.kts kotlin format. The publishing is extension of PluginDependenciesSpec class which is not present in the script.
Here's what worked for me:
plugins {
id("maven-publish")
}
configure<PublishingExtension> {
publications.create<MavenPublication>("myPlugin") {
groupId = "com.myCompany.android"
artifactId = "MyPlugin"
version = "1.0.0"
pom.packaging = "jar"
artifact("$buildDir/libs/MyPlugin.jar")
}
repositories {
mavenLocal()
}
}
I understand where you're coming from, converting from groovy to kotlin script is not a simple one to one translation, and most of us, including myself, code by example. In other words, you just need to see a simple example and you can figure out the rest. This works great when examples are readily available. What you need to do when you don't find an example is to turn to the API document. For example, https://docs.gradle.org/current/dsl/org.gradle.api.publish.PublishingExtension.html shows you the available properties for the PublishingExtension and you can keep drilling in to see what properties you have at the next level. This is especially important when examples may be working with an older version and may no longer be applicable. I will say that it wasn't as obvious is that for accessing extensions in kotlin script, requires the configure block. That's a big difference, but I like that approach, because it makes it clearer what the extension properties are a part of. And by the way, kotlin wants double quote, single quotes are no longer acceptable.

Kotlin DSL add new sourceSet

On Gradle 6.1.1, how to go around adding sourceSets for android project?
The answer on other questions doesn't work anymore, getByName("name") returns error with SourceSet with name 'main' not found.
The official document said to use
sourceSets {
main {
java {
srcDir("thirdParty/src/main/java")
}
}
}
However, there are over 20 main that has to be imported and I'm not sure which one is correct.
I'm using gradle 6.5.1, however documentation suggest, that is should also work for you, try:
sourceSets {
named("main") {
java.srcDir("../buildSrc/src/main/java")
}
}
It's also works for build types (debug/release), flavours etc.
Reason for this is that groovy can somehow interpret itself and knows main etc., but on gradle kts, you have call it using named for already existing, or getByName, create etc. base on need.
Similiar situation is for implement and api in groovy you can just use implementationDebug to attach it only for debug version, but in kotlin dsl you have to call it as a string "implementationDebug", because there is no such function
----- PS -----
If named, getByName not works for you, then try to experiment with findByName and create

Testing inconvenience: Android Studio JUnit vs Gradle based: testOptions ignored by Android Studio

The following was done with Android Studio 3.4, Android Gradle Plugin 3.3.2 and Gradle 4.10.3.
In the build.gradle file, I have configured some unit test options like this:
android {
testOptions {
unitTests.all {
systemProperty "debug","true"
}
}
}
I do have a test function that tries to read this property:
package com.demo;
public class SysPropTestDemo {
#Test
public static void dumpSysProps() {
System.out.println("sysprop(debug)=" + System.getProperty("debug"));
}
}
When run via command line gradlew test --test com.demo.SysPropTestDemo I will get the property debug set correctly to true. If I run the same test via Android Studio without setting any options, the value shown will be null.
In order to get the same result from Android Studio, I explicitly have to enter some values in the "Run/Debug Configurations" panel, i.e something like -Ddebug=true in the VM options.
Now this is a trivial example, but what I really want to do, is to add some path to the java.library.path property in order to be able to load a JNI library compiled within the project. (I do need to write some tests that make use a modified SQLite lib, so not using JNI is not an option here)
It does work when setting additional options, but I think this is very inconvenient, since I can't enter a variable based value in the configuration options (or at least, I don't know how to). To sum it up: when setting or changing values, I do have to go through a bunch of config screens where I would really prefer to have one place in a config file.
Shouldn't Android Studio somehow make use of the values specified in the build.gradle file? If not, the docs don't make it clear that the testOptions.unitTests.all settings can only be used via gradlew invocation.
Skybow,
I feel you have two questions
1. How to load jni lib for androidTest(not for 'test[non instrumented unit tests])
- copy your jni library in corresponding folder [JNI libraries: [app/src/androidTestFLAVORNAMEDebug/jniLibs]
- load your jni library
static {
try {
System.loadLibrary("xyzjni");
} catch (Exception e) {
Logger.error("Exception on loading the jni library : " + e.getMessage());
}
}
2. How to make android studio use your config variables defined for unitTests.
- It would have great if some text file is there which has all configs.
- Or it is part of build.gradle
- I don't have any detail on this.

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.

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