chao2zhang

class R;

chao2zhang

#include "rgbapixel.h"

/**
 * This function constructs a default pixel which is opaque 
 * (non-transparent) and white.
 **/
RGBAPixel::RGBAPixel()
{
	alpha = 255;
	red = 255;

chao2zhang

{
  "coordinates": null,
  "created_at": "Thu Oct 21 16:02:46 +0000 2010",
  "favorited": false,
  "truncated": false,
  "id_str": "28039652140",
  "entities": {
    "urls": [
      {
        "expanded_url": null,

chao2zhang

fun <T> observeUntilFinished(liveData: LiveData<T>, observer: Observer<T>? = null) {
    liveData.observeForever(object : Observer<T> {
        override fun onChanged(resource: Resource<T>?) {
            observer?.onChanged(resource)
            liveData.removeObserver(this) // SAM conversion is not applicable because of `this`
        }
    })
}

chao2zhang

@FunctionalInterface
public interface JavaSam {

    boolean apply(@NotNull Integer id);
}

chao2zhang

// JavaApp.java

private boolean isEven(int id) {
   return id % 2 == 0;
}

public boolean invokeJavaSam(int id, JavaSam sam) {
   return sam.apply(id);
}

chao2zhang

// KotlinApp.kt
typealias KotlinFunction = (Int) -> Boolean

fun invokeKotlinFunction(id: Int, f: KotlinFunction) = f(id)

// JavaApp.java
private void useKotlinFunction() 
   Function1<Integer, Boolean> kotlinFunc = id -> id % 2 == 0;
   KotlinAppKt.invokeKotlinFunction(3, id -> id % 2 == 0);
   KotlinAppKt.invokeKotlinFunction(4, this::isEven);

chao2zhang

fun isEven(id: Int) = id % 2 == 0

fun invokeJavaSam(id: Int, sam: JavaSam) = sam.apply(id)

fun useJavaSam() {
    val javaSam = JavaSam { id -> id % 2 == 0 }
    invokeJavaSam(3, JavaSam { id -> id % 2 == 0 })
    invokeJavaSam(4, JavaSam { isEven(it) })

    // public boolean invokeJavaSam(int id, JavaSam sam);

chao2zhang

fun invokeKotlinInterface(id: Int, i: KotlinInterface) = i.apply(id)

fun useKotlinInterface() {
    val kotlinInterface = object : KotlinInterface {
        override fun apply(id: Int) = id % 2 == 0
    }
    invokeKotlinInterface(3, object : KotlinInterface {
        override fun apply(id: Int) = id % 2 == 0
    })
    invokeKotlinInterface(4, object : KotlinInterface {

chao2zhang

fun invokeKotlinFunction(id: Int, f: KotlinFunction) = f(id)

fun useKotlinFunction() {
    val kotlinFunction : KotlinFunction = { id -> id % 2 == 0 }
    invokeKotlinFunction(3) { id -> id % 2 == 0 }
    invokeKotlinFunction(4) { isEven(it) }
    invokeKotlinFunction(4, ::isEven)
}