Android Multi Touch, drawRect

안드로이드에서 멀티터치를 이용하여 사각형 그리기 연습

res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.example.androidapp.Rect
	    android:id="@+id/myRect"
	    android:layout_width="match_parent"
	    android:layout_height="match_parent" />
	
</LinearLayout>

TestActivity.java

package com.example.androidapp;

import android.app.Activity;
import android.graphics.Point;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.TextView;

public class TestActivity extends Activity {
	
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
	}

} 

Rect.java

package com.example.androidapp;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

public class Rect extends View {

	Paint paint;
	float[] pts;
	
	public Rect(Context context) {
		super(context);
		init();
	}

	public Rect(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}

	public void init() {
		paint = new Paint();
		paint.setColor(Color.RED);
		pts = new float[4];
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		canvas.drawRect(pts[0], pts[1], pts[2], pts[3], paint);
	}
	
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		int action = event.getAction();
		int x,y;
		String str = "";
		//Multi Touch Down,Up을 감지하기 위해서는 아래와 같이 Mask를 사용해야 함
		switch(action & MotionEvent.ACTION_MASK){
			case MotionEvent.ACTION_DOWN:
				break;
			case MotionEvent.ACTION_UP:
				break;
			case MotionEvent.ACTION_POINTER_DOWN:
				int tmp = 0;
				for(int i=0;i<event.getPointerCount();++i){
					int pointer_idx = event.findPointerIndex(i);
					if( pointer_idx == -1 ) continue;
					pts[tmp++] = event.getX(pointer_idx);
					pts[tmp++] = event.getY(pointer_idx);
				}
				break;
			case MotionEvent.ACTION_POINTER_UP:
				break;
			case MotionEvent.ACTION_MOVE:
				break;
		}
		invalidate();
		return true;
	}
}