안드로이드

fillter() 함수

구름나드리 — Wed, 13 Feb 2019 14:02:46 +0900

fillter() 함수


public class FillterEx {

    public static void main(String[] args) {

        Integer[] numbers = {100, 200, 300, 400, 500};
        Single<Integer> single;
        Observable<Integer> source;

        // 1. first : 첫 번째 항목만 리턴 나머지는 모드 걸러낸다.
        single = Observable.fromArray(numbers).first(-1);
        single.subscribe(data -> System.out.println("first(-1) value = " + data));
        System.out.println("======================");

        // 2.  last : 마지막 항목만 리턴
        single = Observable.fromArray(numbers).last(999);
        single.subscribe(data -> System.out.println("last(999) value = " + data));
        System.out.println("======================");

        // 3.  take(N) : 처음부터  N개 데이터만 가져옴
        source = Observable.fromArray(numbers).take(3);
        source.subscribe(data -> System.out.println("take(3) value = " + data));
        System.out.println("======================");

        // 4.  takeLast(N) : 마지막 항목기준으로 N 개의 데이터를 가져 온다
        source = Observable.fromArray(numbers).takeLast(3);
        source.subscribe(data -> System.out.println("takeLast(3) value = " + data));
        System.out.println("======================");

        // 5.  skip(N) : N 개의 항목을 건너 띄고 그 다음 데이터를 활용
        source = Observable.fromArray(numbers).skip(2);
        source.subscribe(data -> System.out.println("skip(2) value = " + data));
        System.out.println("======================");

        // 6.  skipLast(N) : 마지막 옴고을 기준으로 N개의 함목을 제외한 다음 데이터를 활용
        source = Observable.fromArray(numbers).skipLast(3);
        source.subscribe(data -> System.out.println("skipLast(3) value = " + data));
        System.out.println("======================");

    }
}

map 함수

구름나드리 — Thu, 7 Feb 2019 11:23:52 +0900


public class class03 {

    public static void main(String[] args) {

        /*String[] balls = {"1", "2", "3", "4", "5"};
        Observable<String> source = Observable.fromArray(balls)
                .map(getDiamond);

        source.subscribe(System.out::println);*/

        String[] balls = {"RED", "YELLOW", "GREEN", "BLUE"};
        Observable<Integer> source = Observable.fromArray(balls)
                .map(ballToIndex);
        source.subscribe(System.out::println);

    }

    static Function<String, String> getDiamond = ball -> ball + "<>";

    static Function<String, Integer> ballToIndex = ball -> {
        switch (ball) {
            case "RED":
                return 1;
            case "YELLOW":
                return 2;
            case "GREEN":
                return 3;
            case "BLUE":
                return 5;
            default:
                return -1;
        }
    };

: map 함수는 입력값을 어떤 함수에 넣어서 원하는 값으로 변환하는 함수이다.

flatMap() 함수

구름나드리 — Wed, 23 Jan 2019 11:46:30 +0900

flatMap() 함수

:map 함수는 1대1 함수라면 flatMap함수는 일대다 혹은 일대일 Observable 함수이다.


public class FlatMap {


    public static void main(String[] args) {

        String[] ball = {"1", "2", "3", "4", "5"};
        Observable<String> source = Observable.fromArray(ball)
                .flatMap(getDoubleDiamond);
        source.subscribe(System.out::println);

    }

    static  Function<String, Observable<String>> getDoubleDiamond = ball -> Observable.just(ball + "<>", ball + "<>");

}


public class Ex4 {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        System.out.println("GuGuDan Input :" );

        int dan = Integer.parseInt(in.nextLine());

          for (int row = 1; row <= 9; row++) {
            System.out.println( dan + " *  " + row + " = " + dan * row);
        }

        System.out.println("===========================");

        // change for to Observable
        Observable<Integer> source = Observable.range(1, 9);
        source.subscribe(row -> System.out.println( dan + " *  " + row + " = " + dan * row));


        System.out.println("===========================");

        Function<Integer, Observable<String>> gugudan = num ->
                Observable.range(1, 9).map(row -> num + " * " + row + " = " + dan * row);

        Observable<String> source2 = Observable.just(dan).flatMap(gugudan);
        source2.subscribe(System.out::println);


        System.out.println("===========================");

        Observable<String> source3 = Observable.just(dan)
                .flatMap( num -> Observable.range(1, 9)
                                            .map(row -> num + " * " + row + " = " + dan * row)
                );

        source3.subscribe(System.out::println);

    }
}

RxJava Subjsct class

구름나드리 — Fri, 18 Jan 2019 18:39:56 +0900


public class Subject {

    /*
    *  1. AsyncSubject 클래스
    *
    *  Observable 에서 발행한 마지막 데이터만 얻어 어는  subject 클래스 (차가운 Ob 를 뜨거운 Ob로 변경해주는 클래스)
    *
    *  - 완료됨 과 동시에 마지막 데이터를 구독자들에게 전달 (이전 데이터는 전달하지 않는다.)
    *
    * */

    /*
     *  2. BehaviorSubject 클래스
     *
     *  구독자가 구독을 하면 가장 최근 값 혹은 기본값을 넘겨주는 클래스이다.
     *
     * */

    /*
     *  3. PublishSubject 클래스
     *
     *  가장 평범한 Subject 클래스 이다. 오직 해당시간에 발생한 데이터를 그대로 구독자에게 전달 받는다.
     *
     * */

    /*
     *  4. ReplaySubject 클래스
     *
     *  주의 : Subject 클래스의 목적은 뜨거운  Observable 을 활용하는 것인데 차가운 Observable 처럼 동작하기 때문이다.
     *  구독자가 새로 생기면 항상 데이터의 처음부터 끝까지 발행하는 것을 보장해 줍니다.
     *  그러므로 모든 데이터 내용을 저장해두는 과정 중 메로리 누수가 발생할 가능성을 염두에 두고 사용할  때 주의해야 합니다.
     *
     * */
    public static void main(String[] args) {

        // AsyncSubject class
        //ex 1
        AsyncSubject<String> subject = AsyncSubject.create();
        subject.subscribe(data -> System.out.println("subscriber #1 => " + data));
        subject.onNext("1");
        subject.onNext("3");

        subject.subscribe(data -> System.out.println("Subscriber #2 => " + data));
        subject.onNext("5");
        subject.onComplete();

        System.out.println(" ========================== ");

        // ex2
        Float[] temperature = {10.1f, 13.4f, 12.5f};
        Observable<Float> source = Observable.fromArray(temperature);

        AsyncSubject<Float> subject2 = AsyncSubject.create();
        subject2.subscribe(data -> System.out.println("Subscribe #3 => " + data));

        source.subscribe(subject2);

        System.out.println(" ==========================\nBehaviorSubject ");

        //BehaviorSubject
        //ex1
        BehaviorSubject<String> beSubject = BehaviorSubject.createDefault("6");
        beSubject.subscribe(data -> System.out.println("Subscriber #1 => "  + data));
        beSubject.onNext("1");
        beSubject.onNext("3");
        beSubject.subscribe(data -> System.out.println("Subscriber 2 => " + data));
        beSubject.onNext("5");
        beSubject.onComplete();

        System.out.println(" ==========================\nPublishSubject ");

        //PublishSubject class
        // ex1
        PublishSubject<String> puSubject = PublishSubject.create();
        puSubject.subscribe(data -> System.out.println("Subscriber #1 => " + data));
        puSubject.onNext("1");
        puSubject.onNext("3");
        puSubject.subscribe(data -> System.out.println("Subscriber #2 -> " + data));
        puSubject.onNext("5");
        puSubject.onComplete();

        System.out.println(" ==========================\nReplaySubject ");

        //ReplaySubject class
        // ex 1
        ReplaySubject<String> reSubject = ReplaySubject.create();
        reSubject.subscribe(data -> System.out.println("Subscriber #1 => " + data));
        reSubject.onNext("1");
        reSubject.onNext("3");
        reSubject.subscribe(data -> System.out.println("Subscriber #2 => " + data));
        reSubject.onNext("5");
        reSubject.onComplete();

    }

}

데이터 발행자(data source)

데이터 수신자

Observable

Single
Maybe
Subject
Completable

구독자(Subscriber)

옵서버(Observer)
소비자(Consumer)

Java8 Function, Consumer, Predicate, Supplier

구름나드리 — Thu, 10 Jan 2019 15:46:06 +0900

Function, Consumer, Predicate, Supplier


public class FunctionalInterfaceExamples {

    public static void main(String[] args) {
        /**
         *  JAVA 8
         * */

        /**
         * Function : 입력이 있으면 반드시 출력이 있다 (타입 변환)
         */
        Function<String, Integer> toInt = value -> Integer.parseInt(value);
        final Integer number = toInt.apply("100");
        System.out.println(number);
        // Function - identity 
        final Function<Integer, Integer> identity = Function.identity();
        System.out.println(identity.apply(333));

        /**
         * Consumer : 리턴값이 없는 (소비만 한다)
         */
        final Consumer<String> print = s -> System.out.println(s);
        print.accept("Hello");


        /**
         *Predicate : 리턴값은 항상 boolean 이여야 한다.
         */
        Predicate<Integer> isPositive = i -> i > 0;
        Predicate<Integer> lessThan3 = i -> i < 3;

        System.out.println(isPositive.test(1));
        System.out.println(isPositive.test(0));
        System.out.println(isPositive.test(-1));


        //predicate 활용
        List<Integer> numbers = Arrays.asList(-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5);
        /////////////////////// boil code ///////////////////////
        List<Integer> positiveNumbers = new ArrayList<>();
        for (Integer num : numbers) {
            if (isPositive.test(num)) {
                positiveNumbers.add(num);
            }
        }
        List<Integer> numbersLessThan3= new ArrayList<>();
        for (Integer num : numbers) {
            if (lessThan3.test(num)) {
                numbersLessThan3.add(num);
            }
        }

        System.out.println("positive integers:  " + positiveNumbers);
        System.out.println("numbersLessThan3 integers:  " + numbersLessThan3);
        /////////////////////// boil code ///////////////////////

        ///  private static <T> List<T> filter(List<T> list, Predicate<T> filter 메서드 사용
        System.out.println("filter isPositive:  " + filter(numbers, isPositive));
        System.out.println("filter lessThan3:  " + filter(numbers, lessThan3));
        ///////////////////////////////////////////////////////////////////////////////////////////////////


        /**
         * Supplier
         * */
        final Supplier<String> hellSupplier = () -> "Hello " ;
        System.out.println(hellSupplier.get() + "world");

        long start = System.currentTimeMillis();
        printIfValidIndex(0, () -> getVeryExpensiveValue());
        printIfValidIndex(-1, () -> getVeryExpensiveValue());
        printIfValidIndex(-2, () -> getVeryExpensiveValue());
        System.out.println("It took " + (System.currentTimeMillis() - start) / 1000 + " seconds");
    }

    private static  String getVeryExpensiveValue() {
        try {
            TimeUnit.SECONDS.sleep(3);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "Geun ho";
    }

    // predicate 활용
    private static <T> List<T> filter(List<T> list, Predicate<T> filter) {
        List<T> result = new ArrayList<>();
        for (T input :  list) {
            if (filter.test(input)) {
                result.add(input);
            }
        }
        return result;
    }

    // Supplier 활용
    /*private static void printIfValidIndex(int number, String value) {
        if (number >= 0) {
            System.out.println("The value is " + value + " .");
        } else {
            System.out.println("Invalid");
        }
    }*/


    private static void printIfValidIndex(int number, Supplier<String> valueSupplier) {
        if (number >= 0) {
            System.out.println("The value is " + valueSupplier.get() + " .");
        } else {
            System.out.println("Invalid");
        }
    }

}


public class FunctionInterfaceExamples {
    public static void main(String[] args) {

        final Product productA = new Product(1L, "A", new BigDecimal("10.00"));
        final Product productB = new Product(2L, "B", new BigDecimal("55.50"));
        final Product productC = new Product(3L, "C", new BigDecimal("17.45"));
        final Product productD = new Product(4L, "D", new BigDecimal("23.00"));
        final Product productE = new Product(5L, "E", new BigDecimal("110.00"));

        final List<Product> products = Arrays.asList( productA, productB, productC, productD, productE );

        final BigDecimal twenty = new BigDecimal("20");
        List<Product> result = filter( products, product -> product.getPrice().compareTo(twenty) >= 0);

        // DiscountedProducts
        List<Product> expensiveProducts = filter(products, product -> product.getPrice().compareTo(new BigDecimal("50")) > 0);
        List<DiscountedProducts> discountedProducts = map(expensiveProducts,
                product -> new DiscountedProducts(product.getId(), product.getName(), product.getPrice().multiply(new BigDecimal("0.5"))));


        //////////////////////////////////////////////////////////// println /////////////////////////////////////////////////////////////////////////////////

        System.out.println("total products : "  + result);
        System.out.println("products  <= 10 "  + filter(products, product -> product.getPrice().compareTo(new BigDecimal("10")) <= 0));
        System.out.println("expensive products : " + expensiveProducts);
        System.out.println("discounted products : " + discountedProducts);
        System.out.println("30 이하 products " + filter(discountedProducts, d-> d.getPrice().compareTo(new BigDecimal("30")) < 0));

        /*
        --> 이런 작업을 할 필요가 없다.
        final List<BigDecimal> prices = map(products, product -> product.getPrice());
        BigDecimal total = BigDecimal.ZERO;
        for (final BigDecimal price : prices) {
            total = total.add(price);
        }
        */
        BigDecimal total = total(products, product -> product.getPrice());
        System.out.println("total : " + total);

        BigDecimal DisCountedTotal = total(discountedProducts, product -> product.getPrice());
        System.out.println("DisCountedTotal : " + DisCountedTotal);


        Order order = new Order(1L, "on+1234", Arrays.asList(
                new OrderItem(1L, productA, 2),
                new OrderItem(2L, productB, 11),
                new OrderItem(3L, productC, 10)
        ));
        BigDecimal orderTotal = order.totalPrice();
        System.out.println("OrderTotal : " + orderTotal);
        //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    } // end main

    // 필터 compareTo 를 이용 1 , 0 , -1 를 가지고 Predicate 를 이용해서 boolean 결과값을 받고 쌓여진 List 목록을 받는다.
    private static <T> List<T> filter(List<T> list, Predicate<T> predicate) {
        final List<T> result = new ArrayList<>();
        for (final T  t: list) {
            if (predicate.test(t)) {
                result.add(t);
            }
        }
        return result;
    }

    // List<?> 에 어떤 형을 넣어서 다른 형으로 변환 시킨다 (ex) expensiveProducts --> discountedProducts  로 변한
    private static <T, R> List<R> map(List<T> list, Function<T, R> function) {
        final List<R> result = new ArrayList<>();
        for (final T t : list) {
            result.add(function.apply(t));
        }
        return result;
    }

    // 어떤형을 넣든 BigDecimal 형을 변환이 된다면(Function 이용)  total 값을 구할 수 있다.
    private static <T> BigDecimal total(List<T> list, Function<T, BigDecimal> mapper) {
        BigDecimal total = BigDecimal.ZERO;
        for (final T t : list) {
            total = total.add(mapper.apply(t));
        }
        return total;
    }

    /**
     *    lombok 이용
     *    
     *    1. 
     *    lib gradle(모듈레벨) 에 
     *    dependency 에 추가 
     *    compileOnly "org.projectlombok:lombok:1.16.18"
     *    annotationProcessor "org.projectlombok:lombok:1.16.18"
     *  
     *   2. Annotation processors 에 Enable annotation processing 에 체크 
     *   
     *   3. Sysout.out.println 한글 변환 
     *   
     *   모듈 레벨에서 
     *   
     *   dependency 밖에 선언 
     *
     *      compileJava.options.encoding = 'UTF-8'
     *      tasks.withType(JavaCompile){
     *     options.encoding = 'UTF-8'
     * }
     */

    @AllArgsConstructor
    @Data
    static class Product {
        private Long id;
        private String name;
        private BigDecimal price;
    }

    @ToString(callSuper = true)
    static class DiscountedProducts extends Product {

        public DiscountedProducts(Long id, String name, BigDecimal price) {
            super(id, name, price);
        }
    }

    @AllArgsConstructor
    @Data
    static class OrderItem {
        private Long id;
        private Product product;
        private int quantity;

        public BigDecimal getItemTotal() {
            return product.getPrice().multiply(new BigDecimal(quantity));
        }
    }

    @AllArgsConstructor
    @Data
    static class Order {
        private Long id;
        private String orderNumber;
        private List<OrderItem> items;

        public BigDecimal totalPrice() {
            return total(items, items -> items.getItemTotal());
        }
    }

} // end class

EasyPermissions

구름나드리 — Sat, 5 Jan 2019 19:03:15 +0900

EasyPermissions

implementation 'pub.devrel:easypermissions:1.3.+'


<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_permission"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="request Permission"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>


public class MainActivity extends AppCompatActivity implements EasyPermissions.PermissionCallbacks {

    public static final int REQUEST_CODE = 123;
    Button btnOpenCamera;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btnOpenCamera = findViewById(R.id.btn_permission);
        btnOpenCamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openCamera();
            }
        });

    }

    @AfterPermissionGranted(REQUEST_CODE)
    private void openCamera() {
        String[] perms = {Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE};
        if (EasyPermissions.hasPermissions(this, perms)) {
            Toast.makeText(this, "Open Camera ", Toast.LENGTH_SHORT).show();
        } else {
            EasyPermissions.requestPermissions(this, "we need permission ", REQUEST_CODE, perms);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

    @Override
    public void onPermissionsGranted(int requestCode, @NonNull List<String> perms) {
        Log.d("TAG", "why not call ");
    }

    @Override
    public void onPermissionsDenied(int requestCode, @NonNull List<String> perms) {
        if (EasyPermissions.somePermissionDenied(this, String.valueOf(perms))) {
            new AppSettingsDialog.Builder(this).build().show();
            Log.d("TAG", "onPermissionDenied if in ~");
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        Log.d("TAG", "onActivityResult if in method  ~");
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == AppSettingsDialog.DEFAULT_SETTINGS_REQ_CODE) {
            Log.d("TAG", "onActivityResult if in ~");
        }
    }
}

RecyclerView add,remove,delete

구름나드리 — Mon, 3 Dec 2018 14:39:43 +0900

implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:design:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/darker_gray"
        android:padding="4dp"
        android:scrollbars="vertical"
        android:layout_marginBottom="100dp"/>


        <EditText
            android:id="@+id/editext_insert"
            android:inputType="number"
            android:layout_alignParentBottom="true"
            android:layout_alignParentStart="true"
            android:layout_marginStart="15dp"
            android:layout_marginBottom="25dp"
            android:layout_width="40dp"
            android:layout_height="wrap_content" />

        <Button
            android:id="@+id/button_insert"
            android:text="insert"
            android:layout_alignParentBottom="true"
            android:layout_toEndOf="@+id/editext_insert"
            android:layout_marginBottom="25dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

    <EditText
        android:id="@+id/editext_remove"
        android:inputType="number"
        android:layout_alignParentBottom="true"
        android:layout_toLeftOf="@+id/button_remove"
        android:layout_marginStart="15dp"
        android:layout_marginBottom="25dp"
        android:layout_width="40dp"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/button_remove"
        android:text="remove"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_marginBottom="25dp"
        android:layout_marginRight="50dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />



</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <RelativeLayout
        android:layout_margin="4dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/imageView"
            android:padding="2dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <TextView
            android:id="@+id/textView"
            android:layout_alignParentTop="true"
            android:layout_toEndOf="@id/imageView"
            android:text="Line 1"
            android:textColor="@android:color/black"
            android:textSize="20sp"
            android:textStyle="bold"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <TextView
            android:id="@+id/textView2"
            android:layout_below="@id/textView"
            android:layout_toEndOf="@id/imageView"
            android:layout_marginStart="8dp"
            android:text="Line 2"
            android:textSize="15sp"
            android:textStyle="bold"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <ImageView
            android:id="@+id/image_delete"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_alignParentTop="true"
            android:layout_alignParentEnd="true"
            android:src="@drawable/ic_delete_black_24dp" />
    </RelativeLayout>

</android.support.v7.widget.CardView>

package com.example.devat.myapplication;

public class ExampleItem {

    private int mImageResource;
    private String mText1;
    private String mText2;

    public ExampleItem(int mImageResource, String mText1, String mText2) {
        this.mImageResource = mImageResource;
        this.mText1 = mText1;
        this.mText2 = mText2;
    }

    public int getmImageResource() {
        return mImageResource;
    }
    // 
    public void changeTExt1(String text ) {
        mText1 = text;
    }

    public String getmText1() {
        return mText1;
    }

    public String getmText2() {
        return mText2;
    }
}


public class MainActivity extends AppCompatActivity {
    private ArrayList<ExampleItem> exampleItems = new ArrayList<>();
    private RecyclerView recyclerView;
    private ExampleAdapter adapter;
    private RecyclerView.LayoutManager layoutManager;

    private Button buttonInsert;
    private Button buttonRemove;
    private EditText editTextInsert;
    private EditText editTextRemove;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        createExampleList();
        buildRecyclerView();
        setButtons();
    }

    private void setButtons() {
        buttonInsert = findViewById(R.id.button_insert);
        buttonRemove = findViewById(R.id.button_remove);
        editTextInsert = findViewById(R.id.editext_insert);
        editTextRemove = findViewById(R.id.editext_remove);

        buttonInsert.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int position = Integer.parseInt(editTextInsert.getText().toString().trim());
                insertItem(position);
            }
        });

        buttonRemove.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int position = Integer.parseInt(editTextRemove.getText().toString().trim());
                removeItem(position);
            }
        });
    }

    private void insertItem(int position) {
        //Todo modify insert division , out of index check
        exampleItems.add(new ExampleItem(R.drawable.ic_aspect_ratio_black_24dp, "new Item At Position  " + position, "Line " + position));
        adapter.notifyItemInserted(position);
    }

    private void removeItem(int position) {
        // Todo out of index  chceck
        exampleItems.remove(position);
        adapter.notifyItemRemoved(position);
    }

    public void changeItem(int position, String text) {
        exampleItems.get(position).changeTExt1(text);
        adapter.notifyItemChanged(position);
    }

    private void createExampleList() {
        exampleItems = new ArrayList<>();
        exampleItems.add(new ExampleItem(R.drawable.ic_android_black_24dp, ":Line 1", "Lind 2"));
        exampleItems.add(new ExampleItem(R.drawable.ic_adb_black_24dp, ":Line 3", "Lind 4"));
        exampleItems.add(new ExampleItem(R.drawable.ic_aspect_ratio_black_24dp, ":Line 5", "Lind 6"));
        exampleItems.add(new ExampleItem(R.drawable.ic_aspect_ratio_black_24dp, ":Line 7", "Lind 8"));
        exampleItems.add(new ExampleItem(R.drawable.ic_aspect_ratio_black_24dp, ":Line 9", "Lind 10"));
    }

    private void buildRecyclerView() {
        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        layoutManager = new LinearLayoutManager(this);
        adapter = new ExampleAdapter(exampleItems);

        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);

        adapter.setOnItemClickListener(new ExampleAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(int position) {
                changeItem(position, "Clicked");
            }

            @Override
            public void onDeleteClick(int position) {
                removeItem(position);
            }
        });
    }
}


public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> {

    private ArrayList<ExampleItem> mExampleList;
    public OnItemClickListener onItemClickListener;

    public interface OnItemClickListener {
        void onItemClick(int position);
        void onDeleteClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public static class ExampleViewHolder extends RecyclerView.ViewHolder {

        public ImageView imageView;
        public ImageView imageDelete;
        public TextView textView1;
        public TextView textView2;

        public ExampleViewHolder(@NonNull View itemView, final OnItemClickListener onItemClickListener) {
            super(itemView);
            imageView = itemView.findViewById(R.id.imageView);
            textView1 = itemView.findViewById(R.id.textView);
            textView2 = itemView.findViewById(R.id.textView2);
            imageDelete = itemView.findViewById(R.id.image_delete);
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (onItemClickListener != null) {
                        int position = getAdapterPosition();
                        if (position != RecyclerView.NO_POSITION) {
                            onItemClickListener.onItemClick(position);
                        }
                    }
                }
            });

            imageDelete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (onItemClickListener != null) {
                        int position = getAdapterPosition();
                        if (position != RecyclerView.NO_POSITION) {
                            onItemClickListener.onDeleteClick(position);
                        }
                    }
                }
            });

        }
    }

    public ExampleAdapter(ArrayList<ExampleItem> mExampleList) {
        this.mExampleList = mExampleList;
    }

    @NonNull
    @Override
    public ExampleViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.item_layout, viewGroup, false);
        ExampleViewHolder viewHolder = new ExampleViewHolder(v, onItemClickListener);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull ExampleViewHolder holder, int i) {
        ExampleItem currentItem = mExampleList.get(i);
        holder.imageView.setImageResource(currentItem.getmImageResource());
        holder.textView1.setText(currentItem.getmText1());
        holder.textView2.setText(currentItem.getmText2());

    }

    @Override
    public int getItemCount() {
        return mExampleList.size();
    }


}

imeOptions 사용

구름나드리 — Thu, 25 Oct 2018 17:12:18 +0900

imeOptions 사용


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingEnd="16dp"
android:paddingStart="16dp"
android:paddingTop="200dp"
tools:context="com.codinginflow.imeoptionsexample.MainActivity">

<EditText
    android:id="@+id/edit_text1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Username"
    android:inputType="text" />

<EditText
    android:id="@+id/edit_text2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Password"
    android:imeOptions="actionSend"
    android:inputType="textPassword" />

</LinearLayout>


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        EditText editText1 = findViewById(R.id.edit_text1);
        EditText editText2 = findViewById(R.id.edit_text2);
        editText1.setOnEditorActionListener(editorListener);
        editText2.setOnEditorActionListener(editorListener);
    }

    private TextView.OnEditorActionListener editorListener = new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            switch (actionId) {
                case EditorInfo.IME_ACTION_NEXT:
                    Toast.makeText(MainActivity.this, "Next", Toast.LENGTH_SHORT).show();
                    break;
                case EditorInfo.IME_ACTION_SEND:
                    Toast.makeText(MainActivity.this, "Send", Toast.LENGTH_SHORT).show();
                    break;
            }
            return false;
        }
    };
}

HashMap 사용방법

구름나드리 — Thu, 25 Oct 2018 15:34:12 +0900

HashMap 사용방법


public class MapIterationSample {
    public static void main(String[] agrs) {
        Map<String, String> map = new HashMap<String, String>();

        map.put("키1", "값1");
        map.put("키2", "값2");
        map.put("키3", "값3");
        map.put("키4", "값4");
        map.put("키5", "값5");
        map.put("키6", "값6");


        // 방법1
        Iterator<String> keys = map.keySet().iterator();
        while( keys.hasNext() ){
            String key = keys.next();
            System.out.println( String.format("키 : %s, 값 : %s", key, map.get(key)) );
        }

        // 방법2
        for( Map.Entry<String, String> elem : map.entrySet() ){
            System.out.println( String.format("키 : %s, 값 : %s", elem.getKey(), elem.getValue()) );
        }

        // 방법3
        for( String key : map.keySet() ){
            System.out.println( String.format("키 : %s, 값 : %s", key, map.get(key)) );
        }
    }
}

Custom AutoCompleteTextView

구름나드리 — Tue, 23 Oct 2018 16:48:01 +0900

Custom AutoCompleteTextView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <AutoCompleteTextView
        android:id="@+id/actv"
        android:completionThreshold="1"
        android:hint="Select a country"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />


</LinearLayout>


public class MainActivity extends AppCompatActivity {

    private List<CountryItem> countryList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        fillCountryList();

        AutoCompleteTextView editText = findViewById(R.id.actv);
        AutoCompleteAdapter adapter = new AutoCompleteAdapter(this, countryList);
        editText.setAdapter(adapter);

    }

    private void fillCountryList() {

        countryList = new ArrayList<>();
        countryList.add(new CountryItem("Afghanistan", R.drawable.screenshot_11));
        countryList.add(new CountryItem("albanaia", R.drawable.screenshot_12));
        countryList.add(new CountryItem("Algeria", R.drawable.screenshot_13));
        countryList.add(new CountryItem("Korea", R.drawable.screenshot_11));

    }


}


public class CountryItem {
    private String countryName;
    private int flagImage;

    public CountryItem(String countryName, int flagImage) {
        this.countryName = countryName;
        this.flagImage = flagImage;
    }

    public String getCountryName() {
        return countryName;
    }

    public int getFlagImage() {
        return flagImage;
    }

}

<?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="wrap_content"
    android:orientation="horizontal"
    android:padding="4dp"
    xmlns:tools="http://schemas.android.com/tools">

    <ImageView
        android:id="@+id/image_view_flag"
        tools:src="@drawable/screenshot_12"
        android:layout_width="60dp"
        android:layout_height="40dp" />

    <TextView
        android:id="@+id/text_view_name"
        android:layout_gravity="center_vertical"
        android:paddingStart="8dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceListItemSmall"
        tools:text="korea"/>

</LinearLayout>


class AutoCompleteAdapter extends ArrayAdapter<CountryItem> {

    private List<CountryItem> countryListFull;

    public AutoCompleteAdapter(@NonNull Context context, @NonNull List<CountryItem> countryList) {
        super(context, 0, countryList);
        countryListFull = new ArrayList<>(countryList);
    }

    @NonNull
    @Override
    public Filter getFilter() {
        return countryFilter;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(
                    R.layout.country_autocomplete_row, parent, false
            );
        }

        TextView textView = convertView.findViewById(R.id.text_view_name);
        ImageView imageView = convertView.findViewById(R.id.image_view_flag);

        CountryItem countryItem = getItem(position);

        if (countryItem != null) {
            textView.setText(countryItem.getCountryName());
            imageView.setImageResource(countryItem.getFlagImage());
        }
        return convertView;
    }

    private Filter countryFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {

            FilterResults results = new FilterResults();
            List<CountryItem> suggestions = new ArrayList<>();

            if (constraint == null || constraint.length() == 0) {
                suggestions.addAll(countryListFull);
            } else {
                String filterPattern = constraint.toString().toLowerCase().trim();

                for (CountryItem item : countryListFull) {
                    if (item.getCountryName().toLowerCase().contains(filterPattern)) {
                        suggestions.add(item);
                    }
                }
            }

            results.values = suggestions;
            results.count = suggestions.size();

            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            clear();
            addAll((List) results.values);
            notifyDataSetChanged();
        }

        @Override
        public CharSequence convertResultToString(Object resultValue) {
            return ((CountryItem) resultValue).getCountryName();
        }
    };


}