[안드로이드 자바] 간단한 그림판 만들기(onDraw(), onTouchEvent)

 

 

디자인

 

프로젝트 설명

메뉴에서 선, 원, 사각형 형태를 선택할 수 있다.

메뉴에서 색상(빨강, 파랑, 초록)을 선택할 수 있다.

 

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"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

 

java

package com.sample.graphicdraw;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.SubMenu;
import android.view.View;

import static android.graphics.Color.BLUE;
import static android.graphics.Color.GREEN;
import static android.graphics.Color.RED;

public class MainActivity extends AppCompatActivity {

    final static int LINE = 1, CIRCLE=2, RECTANGLE = 3;
    static int curShape=LINE;
    static int curColor = Color.DKGRAY;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyGraphicView(this));
        setTitle("간단 그림판");
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);

        menu.add(0, 1, 0,"선 그리기");
        menu.add(0, 2, 0,"원 그리기");
        menu.add(0, 3, 0,"사각형 그리기");

        SubMenu sMenu = menu.addSubMenu("색상변경>>");
        sMenu.add(0,4,0, "빨강");
        sMenu.add(0,5,0, "초록");
        sMenu.add(0,6,0, "파랑");

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()){
            case 1: curShape=LINE; return true;
            case 2: curShape=CIRCLE; return true;
            case 3: curShape=RECTANGLE; return true;
            case 4: curColor = RED; return true;
            case 5: curColor = GREEN; return true;
            case 6: curColor = BLUE; return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private static class MyGraphicView extends View {
        int startX = -1, startY = -1, stopX = -1, stopY= -1;
        public MyGraphicView(Context context) {
            super(context);
        }

        @Override
        public boolean onTouchEvent(MotionEvent event) {
            switch (event.getAction()){
                case MotionEvent.ACTION_DOWN:
                    startX = (int) event.getX();
                    startY = (int) event.getY();
                    break;
                case MotionEvent.ACTION_MOVE:
                case MotionEvent.ACTION_UP:
                    stopX = (int) event.getX();
                    stopY = (int) event.getY();
                    this.invalidate();
                    break;
            }
            return true;    // super.onTouchEvent(event);
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            Paint paint = new Paint();
            paint.setAntiAlias(true);
            paint.setStrokeWidth(5);
            paint.setStyle(Paint.Style.STROKE);

            switch (curColor) {
                case RED:
                    paint.setColor(Color.RED);
                    break;
                case GREEN:
                    paint.setColor(Color.GREEN);
                    break;
                case BLUE:
                    paint.setColor(Color.BLUE);
                    break;
            }

            switch (curShape) {
                case LINE:
                    canvas.drawLine(startX, startY, stopX, stopY, paint);
                    break;
                case CIRCLE:
                    int radius = (int) Math.sqrt(Math.pow(stopX - startX, 2)
                            + Math.pow(stopY - startY, 2));
                    canvas.drawCircle(startX, startY, radius, paint);
                    break;
                case RECTANGLE:
                    Rect rect = new Rect(startX, startY, stopX, stopY);
                    canvas.drawRect(rect,paint);
                    break;
            }
        }
    }
}