Android開発ではじめるKotlin ref: http://qiita.com/Kogarasi/items/4bd0a37763b057e9d796

file0.txt

Preference->Plugins->Install JetBrain Plugins

file1.txt

Tools->Kotlin->Configure Kotlin in Project

file10.txt

val fab = findViewById(R.id.fab) as FloatingActionButton
fab.setOnClickListener { view -> Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show() }

file11.txt

val a = 1
a = 2

file12.txt

val fab = findViewById( R.id.fab ) as FloatingActionButton

file13.txt

fab.setOnClickListener { view -> Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show() }

file14.txt

fab.setOnClickListener {
  Snackbar.make( it, "Replace with your own action", Snackbar.LENGTH_LONG ).setAction( "Action", null).show()
}

file2.java

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

file3.txt

Code->Convert Java File to Kotlin File

file4.txt

import android.os.Bundle
import android.support.design.widget.FloatingActionButton
import android.support.design.widget.Snackbar
import android.support.v7.app.AppCompatActivity
import android.support.v7.widget.Toolbar
import android.view.View
import android.view.Menu
import android.view.MenuItem

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val toolbar = findViewById(R.id.toolbar) as Toolbar
        setSupportActionBar(toolbar)

        val fab = findViewById(R.id.fab) as FloatingActionButton
        fab.setOnClickListener { view -> Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show() }
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.menu_main, menu)
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        val id = item.itemId

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true
        }

        return super.onOptionsItemSelected(item)
    }
}

file5.java

public class MainActivity extends AppCompatActivity{ ... }

file6.txt

class MainActivity : AppCompatActivity(){ ... }

file7.txt

@Override
public boolean onOptionsItemSelected(MenuItem item){ ... }

file8.txt

override fun onCreateOptionsMenu(menu: Menu): Boolean { ... }

file9.java

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View view) {
    Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
    .setAction("Action", null).show();
  }
});