횽들 안드로이드 멀티터치에 대해 질문좀 할께요 해해

[익명(58.140)]

package com.example.multitouch;

import android.app.Activity;

import android.os.Bundle;

import android.util.EventLog.Event;

import android.view.Menu;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnTouchListener;

import android.widget.TextView;

public class MultiTouchTest extends Activity implements OnTouchListener{

StringBuilder builder = new StringBuilder();

TextView textView;

float[] x = new float[10];

float[] y = new float[10];

boolean[] touched = new boolean[10];

private void updateTextView(){

builder.setLength(0);

for(int i=0;i<10;i++){

builder.append(touched[i]);

builder.append(", ");

builder.append(x[i]);

builder.append(", ");

builder.append(y[i]);

builder.append("\n");

}

textView.setText(builder.toString());

}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

textView = new TextView(this);

textView.setText("Touch and drag (multiple fingers supported)!");

textView.setOnTouchListener(this);

setContentView(textView);

}

 

@Override

public boolean onTouch(View v, MotionEvent event) {

int acti & MotionEvent.ACTION_MASK;

int pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_ID_MASK) >> MotionEvent.ACTION_POINTER_ID_SHIFT;

int pointerId = event.getPointerId(pointerIndex);

switch(action){

case MotionEvent.ACTION_DOWN:

case MotionEvent.ACTION_POINTER_DOWN:

touched[pointerId] = true;

x[pointerId] = (int)event.getX(pointerIndex);

y[pointerId] = (int)event.getY(pointerIndex);

break;

case MotionEvent.ACTION_UP:

case MotionEvent.ACTION_POINTER_UP:

case MotionEvent.ACTION_CANCEL:

touched[pointerId] = false;

x[pointerId] = (int)event.getX(pointerIndex);

y[pointerId] = (int)event.getY(pointerIndex);

break;

case MotionEvent.ACTION_MOVE:

int pointerCount = event.getPointerCount();

for(int i=0;i<pointerCount;i++){

pointerIndex = i;

pointerId = event.getPointerId(pointerIndex);

x[pointerId] = (int)event.getX(pointerIndex);

y[pointerId] = (int)event.getY(pointerIndex);

}

break;

}

updateTextView();

return true;

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

}

.

.

.

내가 안드로이드 멀티터치에 관한 예제를 책에서 봤는데...

public boolean onTouch(View v, MotionEvent event)

{

int acti & MotionEvent.ACTION_MASK;

int pointerIndex = (event.getAction() & MotionEvent.ACTION_POINTER_ID_MASK) >>                                             MotionEvent.ACTION_POINTER_ID_SHIFT;

                  

        int pointerId = event.getPointerId(pointerIndex);

        .

        . 

        .

}

이해가 안가는게

위 소스 코드에서 

대체  pointerIndex 와 

         pointerId       가

서로 무슨 차이가 있는지 모르겠네요

둘다 같은 값을 가리키고 있는거 같은데...

정확히 둘의 용도가 뭔가요?