Argument Builder

WIP...

A Bundle Creator for android Activity and Fragment. it can be used for creating an initial bundler or saving their instance.

Inspired by: fragmentargs

and with a lot of help from KotlinPoet and kotlinx-metadata

I'll put all the resource that I used for creating this module in LearningResource.md file

How to use in your project:

Step 1. Add the JitPack repository to your build file

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
        ...
    }
}

Step 2. Add kotlin-kapt to your app gradle plugin (app:build.gradle)

plugins {
    ...
    id 'kotlin-kapt'
}

Step 3. Add ArgumentBuilder dependencies to your app:build.gradle

implementation "com.github.moodi1999.ArgumentBuilder:argument-annotation:${lastVersion}"
kapt "com.github.moodi1999.ArgumentBuilder:argument-processor:${lastVersion}"

you can find last version in

Step 4. Add @ArgumentBuilderTarget to your Fragment or Activity

@ArgumentBuilderTarget
class MainActivity : AppCompatActivity() {
    ...
}

Step 5. Add @Argument or @SaveInstance to your public mutable argument

Argument

options:

• custom key
• isRequired

@ArgumentBuilderTarget
class MainActivity : AppCompatActivity() {

    @Argument
    var stringArgument = ""


    @Argument
    var mapArgument: Map<Double, Float>? = null

    ...
}

SaveInstance

options:

• customKey

@ArgumentBuilderTarget
class SaveInstanceActivity : AppCompatActivity() {

    @Argument
    @SaveInstance
    var stringArgument = ""

    ...
}

Step 6. build your project.

ArgumentBuilder will generate a class like this for Arguments:

public class MainActivityCreator() {
    private var _bundle: Bundle? = Bundle()

    private val bundle: Bundle
        get() = _bundle!!

    public fun stringArgument(stringArgument: String): MainActivityCreator {
        bundle.putString(stringArgument_arg_key, stringArgument)
        return this
    }

    public fun mapArgument(mapArgument: Map<Double, Float>): MainActivityCreator {
        bundle.putBundle(mapArgument_arg_key, Bundle().apply {
            mapArgument.onEachIndexed { index, (mKey, mValue) ->
                val key_key_1650951646 = """key$index"""
                val value_key_1650951646 = """value$index"""
                putDouble(key_key_1650951646, mKey)
                putFloat(value_key_1650951646, mValue)
            }
        })
        return this
    }

    /**
     * @return copy of [bundle]
     */
    public fun createBundle(): Bundle = Bundle(bundle).also { _bundle = null }

    public companion object {
        private const val stringArgument_arg_key: String = "stringArgument_arg_key"

        private const val mapArgument_arg_key: String = "mapArgument_arg_key"

        public fun initialize(activity: MainActivity): Unit {
            val arguments = requireNotNull(activity.intent.extras) {
                "No arguments set. Have you set up this activity with the @ArgumentBuilderTarget?"
            }
            if (arguments.containsKey(stringArgument_arg_key)) {
                activity.stringArgument = requireNotNull(arguments.getString(stringArgument_arg_key))
            }
            if (arguments.containsKey(mapArgument_arg_key)) {
                activity.mapArgument = requireNotNull(arguments.getBundle(mapArgument_arg_key)?.run {
                    val outMap392637485 = mutableMapOf<Double, Float>()
                    for (index392637485 in 0..(size() / 2)) {
                        val key_key_392637485 = """key$index392637485"""
                        val value_key_392637485 = """value$index392637485"""
                        outMap392637485[getDouble(key_key_392637485)!!] =
                            getFloat(value_key_392637485)!!
                    }
                    outMap392637485
                })
            }
        }
    }
}

or an object like this for SaveInstances:

/**
 * saving Activity state for [SaveInstanceActivity]
 */
public object SaveInstanceActivitySaveInstanceBuilder {
  private const val stringArgument_saveInstance_key: String = "stringArgument_saveInstance_key"

  public fun saveInstanceState(SaveInstanceActivity: SaveInstanceActivity, outState: Bundle): Unit {
    SaveInstanceActivity.apply {
      outState.putString(stringArgument_saveInstance_key, stringArgument)
    }
  }

  public fun restoreSavedInstance(Activity: SaveInstanceActivity, savedInstanceState: Bundle?):
          Unit {
    if (savedInstanceState == null) {
      return
    }
    Activity.apply {
      stringArgument = requireNotNull(savedInstanceState.getString(stringArgument_saveInstance_key))
    }
  }
}

BOCG = Bundle Operation Code Generator

ScalarsTypeBOCG(),
ReferencesTypeBOCG(),
BoxedArrayTypeBOCG(),
EnumTypeBOCG(),
NullableIntArrayTypeBOCG(),
StringAndCharSeqArrayTypeBOCG(),
PrimaryArrayListTypeBOCG(),
ParcelableArrayListTypeBOCG(),
CollectionParameterizedArgTypeBOCG(),
ParcelableSparseArrayTypeBOCG(),
ParcelableArrayTypeBOCG(),
ParcelableTypeBOCG(),
MapEntryIterateTypeBOCG(),
SerializableTypeBOCG(),

These are code generators for supported types, you can check them in argument_processor inside operationGenerator package. They contain a property that checks if the BOCG isApplicable to the given field.

Step 7. criticize or contribute

---

Side notes:

• it just supports kotlin types.
• you can have CustomBundler for nonSupported types. example:

  object SomeLibClassCustomBundler : ArgumentBundler<SomeLibraryClass?> {
      override fun put(key: String?, value: SomeLibraryClass?, bundle: Bundle) {
          val someClassBundle = Bundle()
          requireNotNull(value).run {
              someClassBundle.putString("key", value.name)
              someClassBundle.putInt("key", value.age)
          }
          bundle.putBundle("classBundle", someClassBundle)
      }
  
      override fun <V : SomeLibraryClass?> get(key: String?, bundle: Bundle): V? {
          return bundle.getBundle("classBundle")?.let { 
              // retrieve
          } as V?
      }
  }
  
  class SomeLibraryClass(
      val name: String,
      val age: Int,
  )

---

For Now:

• "for now" it works, but it needs lots of renaming and documentation. => open for criticize and contribution
• it doesn't check all arguments and types constraints.
• there will be reconsideration for Creator class API.

future goals will be in the issue section.