• Настройка Android Studio
• Что будем писать?
• Структура приложения
• Создаем Model
• Экран с заметками
  
  • Создаем MainView и MainPresenter
  • Реализуем поиск по заметкам
  • Реализуем сортировку заметок
• Экран с содержанием заметки
  
  • Создаем NoteView и NotePresenter
  • Реализуем сохранение заметки
• Благодарности
• Заключение

Настройка Android Studio

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-android'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "imangazaliev.notelin"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
        androidTest.java.srcDirs += 'src/androidTest/kotlin'
    }
}

dependencies {
    ...
}

kapt {
    generateStubs = true
}

buildscript {
    ext.kotlin_version = '1.0.2-eap-15'
    repositories {
        mavenCentral()
        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}
repositories {
    mavenCentral()
}

Что будем писать?

Используемые библиотеки

allprojects {
    repositories {
        jcenter()
        mavenCentral()
        maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
        maven { url "https://mvn.arello-mobile.com/" }
        maven { url "https://jitpack.io" }
        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
    }
}

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    compile "com.android.support:appcompat-v7:23.1.1"
    compile 'com.android.support:recyclerview-v7:23.1.1'
    compile 'com.android.support:cardview-v7:23.1.1'
    //дополнительные возможности для Android Kotlin
    compile 'com.pawegio.kandroid:kandroid:0.5.0@aar'
    //ActiveAndroid DB
    compile 'com.michaelpardo:activeandroid:3.1.0-SNAPSHOT'
    //FAB
    compile 'com.melnykov:floatingactionbutton:1.3.0'
    //MaterialDialog
    compile 'com.github.afollestad.material-dialogs:core:0.8.5.6@aar'
    //MVP
    compile 'com.arello-mobile:moxy:0.4.2'
    compile 'com.arello-mobile:moxy-android:0.4.2'
    kapt 'com.arello-mobile:moxy-compiler:0.4.2'
    //RX
    compile 'io.reactivex:rxjava:1.1.0'
    compile 'io.reactivex:rxandroid:1.1.0'
    //Depency Injection
    kapt 'com.google.dagger:dagger-compiler:2.0.2'
    compile 'com.google.dagger:dagger:2.0.2'
    provided 'org.glassfish:javax.annotation:10.0-b28'
    //EventBus
    compile 'org.greenrobot:eventbus:3.0.0'
}

Структура приложения

Создаем Model

• Дата создания
• Дата изменения
• Заголовок
• Текст

class Note : Model {

    @Column(name = "title")
    public var title: String? = null
    @Column(name = "text")
    public var text: String? = null
    @Column(name = "create_date")
    public var createDate: Date? = null
    @Column(name = "change_date")
    public var changeDate: Date? = null

    constructor(title: String, createDate: Date, changeDate: Date) {
        this.title = title
        this.createDate = createDate
        this.changeDate = changeDate
    }

    constructor()

    fun getInfo(): String = "Название:\n$title\n" +
                                       "Время создания:\n${DateUtils.formatDate(createDate)}\n" +
                                       "Время изменения:\n${DateUtils.formatDate(changeDate)}";
}

var note = Note("Новая заметка", Date())
note.save()
...
note.delete()

<meta-data android:name="AA_DB_NAME" android:value="Notelin.db" />
<meta-data android:name="AA_DB_VERSION" android:value="1" />

class NotelinApplication : Application() {
...
}

class NoteWrapper {

    /**
     * Создает новую заметку
     */
    fun createNote(): Note {
        var note = Note("Новая заметка", Date())
        note.save()
        return note
    }

    /**
     * Сохраняет заметку в БД
     */
    fun saveNote(note: Note) : Long {
        return note.save()
    }

    /**
     * Загружает все существующие заметки и передает во View
     */
    fun loadAllNotes() : List<Note> {
        return Select().from(Note::class.java).execute<Note>()
    }

    /**
     * Ищет заметку по id и возвращает ее
     */
    fun getNoteById(noteId:Long) : Note {
        return Select().from(Note::class.java).where("id = ?", noteId).executeSingle<Note>()
    }

    /**
     * Удаляет все существующие заметки
     */
    fun deleteAllNotes()  {
        Delete().from(Note::class.java).execute<Note>();
    }

    /**
     * Удаляет заметку по id
     */
    fun deleteNote(note:Note)  {
        note.delete()
    }

}

Экран с заметками

Создаем MainView и MainPresenter

@StateStrategyType(value = AddToEndSingleStrategy::class)
interface MainView : MvpView {

    fun onNotesLoaded(notes: ArrayList<Note>)

    fun updateView()

    fun onSearchResult(notes: ArrayList<Note>)

    fun onAllNotesDeleted()

    fun onNoteDeleted()

    fun showNoteInfoDialog(noteInfo: String)

    fun hideNoteInfoDialog()

    fun showNoteDeleteDialog(notePosition: Int)

    fun hideNoteDeleteDialog()

    fun showNoteContextDialog(notePosition: Int)

    fun hideNoteContextDialog()

}

class MainActivity : MvpAppCompatActivity(), MainView {

class MainActivity : MainView, MvpAppCompatActivity() {

@InjectViewState
class MainPresenter : MvpPresenter<MainView> {

}

@Module
class NoteWrapperModule {

    @Provides
    @Singleton
    fun provideNoteWrapper() : NoteWrapper= NoteWrapper()

}

@Singleton
@Component(modules = arrayOf(NoteWrapperModule::class))
interface AppComponent {

    fun inject(mainPresenter : MainPresenter)

}

class NotelinApplication : Application() {

    companion object {
        lateinit var graph: AppComponent
    }

    override fun onCreate() {
        super.onCreate()

        graph = DaggerAppComponent.builder().noteWrapperModule(NoteWrapperModule()).build()
    }

}

@InjectViewState
class MainPresenter : MvpPresenter<MainView> {

    @Inject
    lateinit var mNoteWrapper: NoteWrapper

    constructor() : super() {
        NotelinApplication.graph.inject(this)
    }

}

@InjectPresenter
lateinit var mPresenter: MainPresenter

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.activities.MainActivity">
    <TextView
        android:id="@+id/tvNotesIsEmpty"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/notes_is_empty"
        android:gravity="center"
        />
    <android.support.v7.widget.RecyclerView
        android:id="@+id/rvNotesList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        app:layoutManager="android.support.v7.widget.LinearLayoutManager"
        />
    <com.melnykov.fab.FloatingActionButton
        android:id="@+id/fabButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|right"
        android:layout_margin="16dp"
        android:src="@mipmap/ic_add"
        app:fab_colorNormal="@color/colorPrimary"
        app:fab_colorPressed="@color/colorPrimaryDark" />
</FrameLayout>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

    }

fabButon.attachToRecyclerView(rvNotesList)

import kotlinx.android.synthetic.main.activity_main.*

override fun onFirstViewAttach() {
    super.onFirstViewAttach()

    loadAllNotes()
    }

/**
* Загружает все существующие заметки и передает во View
*/
fun loadAllNotes() {
    mNotesList = mNoteWrapper.loadAllNotes() as ArrayList<Note>
    viewState.onNotesLoaded(mNotesList)
}

class NotesAdapter : RecyclerView.Adapter<NotesAdapter.ViewHolder> {

    private var mNotesList: List<Note> = ArrayList()

    constructor(notesList: List<Note>) {
        mNotesList = notesList
    }

    /**
     * Создание новых View и ViewHolder элемента списка, которые впоследствии могут переиспользоваться.
     */
    override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): ViewHolder {
        var v = LayoutInflater.from(viewGroup.context).inflate(R.layout.note_item_layout, viewGroup, false);
        return ViewHolder(v);
    }

    /**
     * Заполнение виджетов View данными из элемента списка с номером i
     */
    override
    fun onBindViewHolder(viewHolder: ViewHolder, i: Int) {
        var note = mNotesList[i];
        viewHolder.mNoteTitle.text = note.title;

        viewHolder.mNoteDate.text = DateUtils.formatDate(note.changeDate);
    }

    override fun getItemCount(): Int {
        return mNotesList.size
    }

    /**
     * Реализация класса ViewHolder, хранящего ссылки на виджеты.
     */

    class ViewHolder : RecyclerView.ViewHolder {

        var mNoteTitle: TextView
        var mNoteDate: TextView

        constructor(itemView: View) : super(itemView) {
            mNoteTitle = itemView.findViewById(R.id.tvItemNoteTitle) as TextView
            mNoteDate = itemView.findViewById(R.id.tvItemNoteDate) as TextView
        }

    }

}

class DateUtils {

    companion object {

        fun formatDate(date: Date?): String {
            var dateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm");
            return dateFormat.format(date)
        }

    }

}

override fun onNotesLoaded(notes: ArrayList<Note>) {
    rvNotesList.adapter = NotesAdapter(notes)
    updateView()
}

override fun updateView() {
    rvNotesList.adapter.notifyDataSetChanged()
    if (rvNotesList.adapter.itemCount == 0) {
        rvNotesList.visibility = View.GONE
        tvNotesIsEmpty.visibility = View.VISIBLE
    } else {
        rvNotesList.visibility = View.VISIBLE
        tvNotesIsEmpty.visibility = View.GONE
    }
}

public class ItemClickSupport {

    private final RecyclerView mRecyclerView;
    private OnItemClickListener mOnItemClickListener;
    private OnItemLongClickListener mOnItemLongClickListener;

    private View.OnClickListener mOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mOnItemClickListener != null) {
                RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
                mOnItemClickListener.onItemClicked(mRecyclerView, holder.getAdapterPosition(), v);
            }
        }
    };

    private View.OnLongClickListener mOnLongClickListener = new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            if (mOnItemLongClickListener != null) {
                RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
                return mOnItemLongClickListener.onItemLongClicked(mRecyclerView, holder.getAdapterPosition(), v);
            }
            return false;
        }
    };

    private RecyclerView.OnChildAttachStateChangeListener mAttachListener = new RecyclerView.OnChildAttachStateChangeListener() {
        @Override
        public void onChildViewAttachedToWindow(View view) {
            if (mOnItemClickListener != null) {
                view.setOnClickListener(mOnClickListener);
            }
            if (mOnItemLongClickListener != null) {
                view.setOnLongClickListener(mOnLongClickListener);
            }
        }

        @Override
        public void onChildViewDetachedFromWindow(View view) {

        }
    };

    private ItemClickSupport(RecyclerView recyclerView) {
        mRecyclerView = recyclerView;
        mRecyclerView.setTag(R.id.item_click_support, this);
        mRecyclerView.addOnChildAttachStateChangeListener(mAttachListener);
    }

    public static ItemClickSupport addTo(RecyclerView view) {
        ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
        if (support == null) {
            support = new ItemClickSupport(view);
        }
        return support;
    }

    public static ItemClickSupport removeFrom(RecyclerView view) {
        ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
        if (support != null) {
            support.detach(view);
        }
        return support;
    }

    public ItemClickSupport setOnItemClickListener(OnItemClickListener listener) {
        mOnItemClickListener = listener;
        return this;
    }

    public ItemClickSupport setOnItemLongClickListener(OnItemLongClickListener listener) {
        mOnItemLongClickListener = listener;
        return this;
    }

    private void detach(RecyclerView view) {
        view.removeOnChildAttachStateChangeListener(mAttachListener);
        view.setTag(R.id.item_click_support, null);
    }

    public interface OnItemClickListener {
        void onItemClicked(RecyclerView recyclerView, int position, View v);
    }

    public interface OnItemLongClickListener {
        boolean onItemLongClicked(RecyclerView recyclerView, int position, View v);
    }
}

        with(ItemClickSupport.addTo(rvNotesList)) {
            setOnItemClickListener { recyclerView, position, v -> mPresenter.openNote(this@MainActivity, position) }
            setOnItemLongClickListener { recyclerView, position, v -> mPresenter.showNoteContextDialog(position); true }
        }

/**
* Открывает активити с заметкой по позиции
*/
fun openNote(activity: Activity, position: Int) {
    val intent = Intent(activity, NoteActivity::class.java)
    intent.putExtra("note_id", mNotesList[position].id)
    activity.startActivity(intent)
}

/**
* Показывает контекстное меню заметки
*/
fun showNoteContextDialog(position: Int) {
    viewState.showNoteContextDialog(position)
}

/**
 * Прячет контекстное меню заметки
*/
fun hideNoteContextDialog() {
    viewState.hideNoteContextDialog()
}

fabButton.setOnClickListener {
            mPresenter.openNewNote(this)
}

fun openNewNote(activity: Activity) {
        val newNote = mNoteWrapper.createNote()
        mNotesList.add(newNote)
        sortNotesBy(getCurrentSortMethod())
        openNote(activity, mNotesList.indexOf(newNote))
}

Реализуем поиск по заметкам

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/action_search"
        android:icon="@android:drawable/ic_menu_search"
        android:title="@string/search"
        app:actionViewClass="android.support.v7.widget.SearchView"
        app:showAsAction="always" />

</menu>

override fun onCreateOptionsMenu(menu: Menu): Boolean {
    menuInflater.inflate(R.menu.main, menu)

    initSearchView(menu)
    return true
}

private fun initSearchView(menu: Menu) {
    var searchViewMenuItem = menu.findItem(R.id.action_search);
    var searchView = searchViewMenuItem.actionView as SearchView;
    searchView.onQueryChange { query -> mPresenter.search(query) }
    searchView.setOnCloseListener { mPresenter.search(""); false }
}

/**
* Ищет заметку по имени
*/
fun search(query: String) {
    if (query.equals("")) {
        viewState.onSearchResult(mNotesList)
    } else {
        val searchResults = mNotesList.filter { note -> note.title!!.toLowerCase().startsWith(query.toLowerCase()) }
        viewState.onSearchResult(searchResults as ArrayList<Note>)
    }
}

override fun onSearchResult(notes: ArrayList<Note>) {
    rvNotesList.adapter = NotesAdapter(notes)
}

Реализуем сортировку заметок

<item android:title="@string/sort_by">
    <menu>
        <item
            android:id="@+id/menuSortByName"
            android:title="@string/sort_by_title" />
        <item
            android:id="@+id/menuSortByDate"
            android:title="@string/sort_by_date" />
    </menu>
</item>

override fun onOptionsItemSelected(item: MenuItem): Boolean {
        when (item.itemId) {
            R.id.menuSortByName -> mPresenter.sortNotesBy(MainPresenter.SortNotesBy.NAME)
            R.id.menuSortByDate -> mPresenter.sortNotesBy(MainPresenter.SortNotesBy.DATE)
        }
    return super.onOptionsItemSelected(item)
}

/**
* Сортирует заметки
*/
fun sortNotesBy(sortMethod: SortNotesBy) {
    mNotesList.sortWith(getSortComparator(sortMethod))
    viewState.updateView()
}

fun getSortComparator(sortMethod: SortNotesBy): Comparator<Note> {
    when (sortMethod) {
        SortNotesBy.NAME -> return SortName()
        SortNotesBy.DATE -> return SortDate()
    }
}

/**
 * Cортировка заметок по дате
 */
class SortDate : Comparator<Note> {
    override fun compare(note1: Note, note2: Note): Int {
        return  note1.changeDate!!.compareTo(note2.changeDate!!)
    }

}

/**
 * Cортировка заметок по имени
 */
class SortName : Comparator<Note> {
    override fun compare(note1: Note, note2: Note): Int {
        return  note1.title!!.compareTo(note2.title!!)
    }

}

Экран с содержанием заметки

Создаем NoteView и NotePresenter

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <EditText
        android:id="@+id/etTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:background="#EEEEEE"
        android:textColor="#212121"
        android:paddingLeft="10dp"
        android:paddingTop="10dp"
        android:paddingBottom="5dp"
        android:hint="Заголовок"
        />

    <TextView
        android:id="@+id/tvNoteDate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:background="#EEEEEE"
        android:textColor="#212121"
        android:paddingLeft="10dp"
        android:paddingBottom="10dp"
        />

    <EditText
        android:id="@+id/etText"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textColor="#000000"
        android:gravity="start"
        android:hint="Текст"
        android:background="@null"
        android:paddingLeft="10dp"
        />

</LinearLayout>

class MyActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        MyActivityUI().setContentView(this)
    }
}

class MyActivityUI : AnkoComponent {

    companion object {
        val ET_TITLE_ID = View.generateViewId()
        val TV_NOTE_DATE_ID = View.generateViewId()
        val ET_TEXT_ID = View.generateViewId()
    }
    
    override fun createView(ui: AnkoContext<MainActivit>) = with(ui) {
        verticalLayout { 
            editText { 
                id = ET_TITLE_ID
                singleLine = true
                backgroundColor = 0xEE.gray.opaque
                textColor = 0x21.gray.opaque
                leftPadding = dip(10)
                topPadding = dip(10)
                bottomPadding = dip(5)
                hint = "Заголовок"
            }.lparams(matchParent, wrapContent)
            
            textView {
                id = TV_NOTE_DATE_ID
                singleLine = true
                backgroundColor = 0xEE.gray.opaque
                textColor = 0x21.gray.opaque
                leftPadding = dip(10)
                bottomPadding = dip(10)
            }.lparams(matchParent, wrapContent)
            
            editText { 
                id = ET_TEXT_ID
                textColor = Color.BLACK
                gravity = Gravity.START
                hint = "Текст"
                background = null
                leftPadding = dip(10)
            }
        }
    }
}

interface NoteView : MvpView {

    fun showNote(note: Note)

    fun onNoteSaved()

    fun onNoteDeleted()

    fun showNoteInfoDialog(noteInfo: String)

    fun hideNoteInfoDialog()

    fun showNoteDeleteDialog()

    fun hideNoteDeleteDialog()

}

class NoteActivity : MvpAppCompatActivity(), NoteView {

    @InjectPresenter
    lateinit var mPresenter: NotePresenter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_note)

        val noteId = intent.extras.getLong("note_id", -1)
        mPresenter.showNote(noteId)
    }

}

@InjectViewState
class NotePresenter : MvpPresenter<NoteView> {

    @Inject
    lateinit var mNoteWrapper: NoteWrapper
    lateinit var mNote: Note

    constructor() : super() {
        NotelinApplication.graph.inject(this)
    }

    fun showNote(noteId: Long) {
        mNote = mNoteWrapper.getNoteById(noteId)
        viewState.showNote(mNote)
    }

}

fun inject(notePresenter: NotePresenter)

override fun showNote(note: Note) {
    tvNoteDate.text = DateUtils.formatDate(note.changeDate)
    etTitle.setText(note.title)
    etText.setText(note.text)
}

Реализуем сохранение заметки

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    >
    <item
        android:id="@+id/menuSaveNote"
        android:title="@string/save"
        app:showAsAction="never"
        />
</menu>

override fun onCreateOptionsMenu(menu: Menu): Boolean {
    menuInflater.inflate(R.menu.note, menu)
    return true
}

Покажем меню в Activity:

override fun onOptionsItemSelected(item: MenuItem): Boolean {
    when (item.itemId) {
        R.id.menuSaveNote -> mPresenter.saveNote(etTitle.text.toString(), etText.text.toString())
    }
    return super.onOptionsItemSelected(item)
}

Благодарности

Заключение