2-6-2 스피너 사용하기

MainActivity

package com.example.boostcoursepractice;
 
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
 
import android.content.Context;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Spinner;
import android.widget.TextView;
 
import com.google.android.material.snackbar.Snackbar;
 
import org.w3c.dom.Text;
 
public class MainActivity extends AppCompatActivity {
 
    String[] items = {"소녀시대", "걸스데이", "티아라", "여자친구"};
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        Spinner spinner = (Spinner) findViewById(R.id.spinner);
        final TextView textView = (TextView) findViewById(R.id.textView);
 
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, items);
 
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
 
        spinner.setAdapter(adapter);
 
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                textView.setText(items[i]);
            }
 
            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {
                textView.setText("선택안됨");
            }
        });
 
    }
 
}
 

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    >
 
    <Spinner
        android:id="@+id/spinner"
        android:layout_width="395dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.499" />
 
    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="선택 :"
        android:textSize="40dp"
        app:layout_constraintBottom_toTopOf="@+id/spinner"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

 

스피너도 기본적으로 어댑터를 이용하는데 아래와 같이

 

 ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, items);

 

ArrayAdapter가 따로 있어 바로 사용할 수 있다. 

 

 

스피너의 아이템 선택 이벤트처리는 다음과 같이

 

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

            @Override

            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {

                textView.setText(items[i]);

            }

 

            @Override

            public void onNothingSelected(AdapterView<?> adapterView) {

                textView.setText("선택안됨");

            }

        });

 

AdapterView.OnItemSelectedListener를 리스너로 등록해주고 그 안의 onItemSelected, onNothingSelected를 오버라이드 해주면 된다.

 

 

결과화면