[모바일프로그래밍] 7-2 터치이벤트와의 연결

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {
    final static int LINE = 1, RECT = 2, CIRCLE = 3;
    static int kindofshape = LINE;

    private static class MyGraphicView extends View {
        int startX, startY, endX, endY;
        public MyGraphicView(Context myContext) {
            super(myContext);
        }

        @Override
        public boolean onTouchEvent(MotionEvent myEvent) {
            switch (myEvent.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    startX = (int)myEvent.getX();
                    startY = (int)myEvent.getY();
                    break;
                case MotionEvent.ACTION_MOVE:
                case MotionEvent.ACTION_UP:
                    endX = (int)myEvent.getX();
                    endY = (int)myEvent.getY();
                    this.invalidate();
                    break;
            }
            return true;
        }
        protected void onDraw(Canvas myCanvas) {
            super.onDraw(myCanvas);
            Paint myPaint = new Paint();
            myPaint.setAntiAlias(true);
            myPaint.setStrokeWidth(8);
            myPaint.setStyle(Paint.Style.STROKE);
            myPaint.setColor(Color.RED);

            switch (kindofshape) {
                case LINE:
                    myCanvas.drawLine(startX, startY, endX, endY, myPaint);
                    break;
                case RECT:
                    myCanvas.drawRect(startX, startY, endX, endY, myPaint);
                    break;
                case CIRCLE:
                    int radius = (int)Math.sqrt(Math.pow((endX - startX), 2.0) + Math.pow((endY - startY), 2.0));
                    myCanvas.drawCircle(startX, startY, radius, myPaint);
                    break;
            }
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyGraphicView(this));
    }
    public boolean onCreateOptionsMenu(Menu myMenu) {
        super.onCreateOptionsMenu(myMenu);
        myMenu.add(0, 1, 0, "LINE");
        myMenu.add(0, 2, 0, "RECT");
        myMenu.add(0, 3, 0, "CIRCLE");
        return true;
    }
    public boolean onOptionsItemSelected(MenuItem myItem) {
        switch (myItem.getItemId()) {
            case 1:
                kindofshape = LINE;
                return true;
            case 2:
                kindofshape = RECT;
                return true;
            case 3:
                kindofshape = CIRCLE;
                return true;
        }
        return super.onOptionsItemSelected(myItem);
    }
}