Android / 버튼 클릭시 숫자가 증감하는 로직

버튼 클릭시 숫자가 증감하는 간단한 로직을 구현해보자. 심심풀이로 올리는 포스팅이니 가볍게 보시길 바란다.

 

 

-예제-

 

-코드-

 

activity_main.xml

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingTop="200dp">

        <TextView
            android:id="@+id/tv_count"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="0"
            android:textSize="50sp"
            android:gravity="center"
            tools:layout_editor_absoluteX="196dp"
            tools:layout_editor_absoluteY="232dp" />

    </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:paddingTop="100dp">
        <Button
            android:id="@+id/btn_add"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:text="증가"
            tools:layout_editor_absoluteX="79dp"
            tools:layout_editor_absoluteY="461dp" />

        <Button
            android:id="@+id/btn_minus"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:text="감소"
            tools:layout_editor_absoluteX="252dp"
            tools:layout_editor_absoluteY="461dp" />
    </LinearLayout>
</LinearLayout>

 

MainActivity.java

package com.example.test;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private Button btnAdd, btnMinus;
    private TextView tvCount;
    private int count = 0;

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

        tvCount = findViewById(R.id.tv_count);
        tvCount.setText(count+"");
        btnAdd = findViewById(R.id.btn_add);
        btnMinus = findViewById(R.id.btn_minus);

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                count++;
                tvCount.setText(count+"");
            }
        });

        btnMinus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                count--;
                tvCount.setText(count+"");
            }
        });
    }
}