[Android] Time Picker

Time Picker

 

시간을 선택하기 위한 위젯을 제공하기 위해서, TimePicker 위젯을 사용하며 이것은 사용자가 친숙한 인터페이스로 시, 분을 선택하게 한다.

    여기서 여러분은 TimePickerDialog를 만들며, 이것은 버튼을 눌렀을 때 floating 다이아로그 박스에 time picker를 나타낸다. 사용자가 시간을 설정할 때, TextView가 새로운 시간을 갱신할 것이다.

 

    1. HelloTimePicker 이름의 새로운 프로젝트를 시작한다.

 

    2. res/layout/main.xml 파일을 열고 다음을 삽입한다:

 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:orientation="vertical">

    <TextView android:id="@+id/timeDisplay"

                  android:layout_width="wrap_content"

                  android:layout_height="wrap_content"

                  android:text=""/>

    <Button android:id="@+id/pickTime"

                  android:layout_width="wrap_content"

                  android:layout_height="wrap_content"

                  android:text="Change the time"/>

</LinearLayout>

 

    이것은 TextView를 가진 기본적인 LinearLayout을 만들며, 이 레이아웃은 날짜와 TimePickerDialog를 열어줄 Button을 출력한다.

 

    3. HelloTimePicker.java 파일을 열고 다음의 클래스 멤버를 클래스에 추가한다:

 

private TextView mTimeDisplay;

private Button mPickTime;

private int mHour;

private int mMinute;

static final int TIME_DIALOG_ID = 0;

 

    이것은 레이아웃 엘리먼트와 시간 필드를 위한 변수를 선언한다. TIME_DIALOG_ID는 다이아로그를 고유하게 식별하는 정적인 변수이다.

 

    4. 이제 다음의 코드를 onCreate() 메소드에 추가한다:

 

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    // capture our View elements

    mTimeDisplay = (TextView) findViewById(R.id.timeDisplay);

    mPickTime = (Button) findViewById(R.id.pickTime);

    // add a click listener to the button

    mPickTime.setOnClickListener(new View.OnClickListener() {

                  public void onClick(View v) {

                                   showDialog(TIME_DIALOG_ID);

                  }

    });

    // get the current time

    final Calendar c = Calendar.getInstance();

    mHour = c.get(Calendar.HOUR_OF_DAY);

    mMinute = c.get(Calendar.MINUTE);

    // display the current date

    updateDisplay();

}

 

    우선 content view를 main.xml로 설정한다. 그런 다음에 findViewById(int) 메소드의 반환 레이아웃으로부터 <TextView>와 <Button> 엘리먼트를 알아낸다. Button을 위한 새로운 View.OnClickListener가 만들어지며, 버튼을 클릭하였을 때 이것은 time picker 다이아로그를 위한 고유한 정수 ID를 전달하면서 showDialog(int) 메소드를 호출할 것이다. showDialog(int) 메소드를 사용하는 것은 activity가 다이아로그의 생명 주기를 관리하게 하며, 또한 이것은 출력되어야 할 Dialog를 요청하기 위해 onCreateDialog(int) 회답 호출 메소드를 호출할 것이다. on-click listener가 설정된 다음에, 현재의 시간과 분을 구하기 위해 새로운 Calendar가 만들어진다. 마지막으로 현재의 날짜를 가진 TextView를 채우지 위해 private updateDisplay() 메소드를 호출한다.

 

    5. updateDisplay()와 pad() 메소드를 추가한다:

 

// updates the time we display in the TextView

private void updateDisplay() {

    mTimeDisplay.setText(

                  new StringBuilder()

                                   .append(pad(mHour)).append(":")

                                   .append(pad(mMinute)));

}

 

private static String pad(int c) {

    if (c >= 10)

                  return String.valueOf(c);

    else

                  return "0" + String.valueOf(c);

}

 

    updateDisplay() 메소드는 시간을 위한 멤버 필드들을 사용하며, 이들을 TextView(즉, mTimeDisplay)에 삽입한다. pad() 메소드는 시간과 분에 대한 적절한 스트링 표현을 반환한다.

 

    6. TimePickerDialog.OnTimeSetListener(즉, 사용자가 새로운 시간을 설정할 때 호출됨)를 위한 클래스 멤버를 추가한다:

 

// the callback received when the user "sets" the time in the dialog

private TimePickerDialog.OnTimeSetListener mTimeSetListener =

    new TimePickerDialog.OnTimeSetListener() {

                  public void onTimeSet(TimePicker view, int hourOfDay, int minute) {

                                   mHour = hourOfDay;

                                   mMinute = minute;

                                   updateDisplay();

                  }

    };

 

    사용자가 “Set” 버튼을 클릭하여 날짜를 설정할 때, onTimeSet() 회답 호출 메소드를 호출하며, 이것은 새로운 시간으로 멤버 필드를 갱신하고 레이아웃의 TextView를 갱신한다.

 

    7. 이제 onCreateDialog(int) 회답 호출 메소드를 추가한다:

 

@Override

protected Dialog onCreateDialog(int id) {

    switch (id) {

    case TIME_DIALOG_ID:

                  return new TimePickerDialog(this, mTimeSetListener, mHour, mMinute, false);

    }

    return null;

}

 

    이것은 Activity 회답 호출 메소드이며, 여러분이 Button의 on-click listener에서 showDialog(int)로 넘겨준 식별자가 이것으로 전달된다. ID가 일치할 때, 이것은 onCreate() 메소드의 끝에서 초기화된 멤버 변수와 이전의 단계에서 만들어진 TimePickerDialog.OnTimeSetListener를 가지고 TimePickerDialog를 초기화한다.

 

    8. 응용프로그램을 실행한다. “Change the time” 버튼을 눌렀을 때, 여러분은 다음의 그림을 보아야 한다: