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I built an app with Kotlin, and my client still paid me

A few months ago I started a rewrite project for a client, and they agreed to let me use Kotlin despite the fact I had never written anything substantial in the language prior. I thought it would be fun to learn something new, but was surprised by how much more productive this new tool made me. In this talk you will learn about Kotlin, my experience writing a real production app in it, and why you should give it serious consideration.

Kotlin is a language developed by JetBrains for the JVM. It includes language features such as lambdas, data classes, extension methods and null safety, that will make even the best developer write more accurate, easier to read and maintain code. I plan to give everyone a working understanding of the syntax, features, risks and most importantly what I learned from building a production app in Kotlin. The only prerequisite for the talk will be a decent understanding of Java and Android app construction.

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private ObjectAnimator animateRegularProgress(int finalProgress) {
    ObjectAnimator animation = ObjectAnimator.ofInt(regularProgressBar, PROPERTY_NAME, 0, finalProgress);
    animation.setDuration(ANIM_PROGRESS);
    animation.setInterpolator(new LinearInterpolator());

    return animation;
}

private void animateTextProgress(float end, float total, ObjectAnimator barAnimationToCoupleTo) {

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package com.mozu.mozuandroidinstoreassistant.app.loaders;

import com.mozu.api.MozuApiContext;
import com.mozu.api.contracts.productadmin.LocationInventoryCollection;
import com.mozu.api.contracts.productruntime.Product;
import com.mozu.api.resources.commerce.catalog.admin.products.LocationInventoryResource;

import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;

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package com.mozu.mozuandroidinstoreassistant.app.loaders;

import com.mozu.api.MozuApiContext;
import com.mozu.api.contracts.productadmin.LocationInventoryCollection;
import com.mozu.api.contracts.productruntime.Product;
import com.mozu.api.resources.commerce.catalog.admin.products.LocationInventoryResource;

import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;

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package com.mozu.mozuandroidinstoreassistant.app.loaders;

import com.mozu.api.MozuApiContext;
import com.mozu.api.contracts.productadmin.LocationInventoryCollection;
import com.mozu.api.contracts.productruntime.Product;
import com.mozu.api.resources.commerce.catalog.admin.products.LocationInventoryResource;

import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;

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public class ReboundScaleActivity extends Activity implements View.OnTouchListener, SpringListener {

    private static double TENSION = 800;
    private static double DAMPER = 20; //friction

    private ImageView mImageToAnimate;
    private SpringSystem mSpringSystem;
    private Spring mSpring;

    @Override

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public class ReboundTranslateActivity extends Activity implements View.OnClickListener, SpringListener {

    private static double TENSION = 800;
    private static double DAMPER = 20; //friction

    private ImageView mImageToAnimate;
    private SpringSystem mSpringSystem;
    private Spring mSpring;

    private boolean mMovedUp = false;

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Bitmap bitmap = ((BitmapDrawable)viewHolder.productImage.getDrawable()).getBitmap();

int [] colors = new int[1];
colors[0] = bitmap.getPixel(0, 0);

Bitmap backgroundBitmap = Bitmap.createBitmap(colors, 1, 1, Bitmap.Config.ARGB_8888);

viewHolder.productImage.setBackgroundDrawable(new BitmapDrawable(backgroundBitmap));

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    Collections.sort(tenants, new ScopeComparator());
    
    public class ScopeComparator implements Comparator<Scope> {

        @Override
        public int compare(Scope lhs, Scope rhs) {

            return lhs.getName().compareTo(rhs.getName());
        }

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private CategoryFragmentListener mListener = sCategoryListener;

private static CategoryFragmentListener sCategoryListener = new CategoryFragmentListener() {

    @Override
    public void onLeafCategoryChosen() {

    }
    
};