Passing key-value pairs with Bundle is the most common approach of exchanging data across Android components. Unfortunately, much of the process of sending and receiving those key-value pairs (known as extra) requires a lot of boilerplate code. Auto Bundler aims to minify the process with annotation processing.

public class ExampleActivity extends Activity {
    @Extra String username;
    @State int position;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Bundler.bindExtras(this);
        Bundler.bindStates(this, savedInstanceState);
        // TODO: Use fields...
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        Bundler.saveStates(this, outState);
    }
}

repositories {
    mavenCentral()
}
dependencies {
    implementation "com.hendraanggrian.auto:bundle:$version"
    annotationProcessor "com.hendraanggrian.auto:bundle-compiler:$version" // or kapt for Kotlin
}

@BindExtra for binding extra value to field, field cannot be private. When key is not provided, field name will be used as the key.

@BindExtra @JvmField var username: String

Create extras with varargs argument with extrasOf(). This is optional, any Bundle would work just fine.

Intent intent = new Intent(context, ExampleActivity.class);
intent.putExtras(Bundler.extrasOf(ExampleActivity.class, "Hendra Anggrian", 24));
startActivity(intent);

@BindState for binding extra value to field, field cannot be private. When key is not provided, field name will be used as the key.

@BindExtra @JvmField var position: Int

override fun onRestoreInstanceState(savedInstanceState: Bundle) {
    super.onRestoreInstanceState(savedInstanceState)
    restoreStates(savedInstanceState)
}

Simply call Bundle.saveStates() to save states.

override fun onSaveInstanceState(outState: Bundle) {
   super.onSaveInstanceState(outState)
   saveStates(outState)
}

• primitive data types and array of them.
• CharSequence, CharSequence[], and ArrayList<CharSequence>
• String, String[], and ArrayList<String>
• Parcelable, Parcelable[], ArrayList<Parcelable> and SparseArray<Parcelable>
• Serializable

[Parceler][parceler] is supported with this library, it is a library that easily makes any object implements Parcelable with generated code, making it able to be inserted to Bundle as Parcelable.

Bundler.wrap() automatically converts the object to Parcelable. Without Bundler.wrap(), object must be wrapped using Parcels.wrap(). Head to [Parceler doc][parceler] for more information.

User user = new User("Hendra Anggrian", 24);
// with Bundler.wrap()
intent.putExtras(Bundler.wrap(UserActivity.class, user));
// without Bundler.wrap()
intent.putExtra("user", Parcels.wrap(user));

Bundler.bind() automatically converts the Parcelable back to original object.

class UserActivity : Activity {
    @Extra("user") lateinit var user : User

    override fun onCreate(savedInstanceState : Bundle) {
        super.onCreate(savedInstanceState)
        bindExtras()
    }
}

Extra bindings are required by default, an exception will be thrown if key is not found in Bundle. If this is not a desired behavior, annotate the field with @Nullable from [Android's support design library][support-annotations].

@Nullable @BindExtra String username;