Tested on Nexus One running 2.2.1. It can be noticed that there are some problem on multitouch detection on Nexus One!
MultiTouchView.java
package com.exercise.AndroidTouch;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class MultiTouchView extends View {
private final int TOUCH_CNT = 2;
private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
float[] x = new float[TOUCH_CNT];
float[] y = new float[TOUCH_CNT];
boolean[] isTouch = new boolean[TOUCH_CNT];
public MultiTouchView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public MultiTouchView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public MultiTouchView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec),
MeasureSpec.getSize(heightMeasureSpec));
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
if(isTouch[0]){
paint.setStrokeWidth(1);
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.FILL);
canvas.drawCircle(x[0], y[0], 75f, paint);
}
if(isTouch[1]){
paint.setStrokeWidth(1);
paint.setColor(Color.BLUE);
paint.setStyle(Paint.Style.FILL);
canvas.drawCircle(x[1], y[1], 75f, paint);
}
}
@Override
public boolean onTouchEvent(MotionEvent motionEvent) {
// TODO Auto-generated method stub
int pointerIndex = ((motionEvent.getAction() & MotionEvent.ACTION_POINTER_ID_MASK)
>> MotionEvent.ACTION_POINTER_ID_SHIFT);
int pointerId = motionEvent.getPointerId(pointerIndex);
int action = (motionEvent.getAction() & MotionEvent.ACTION_MASK);
int pointCnt = motionEvent.getPointerCount();
if (pointCnt <= TOUCH_CNT){
if (pointerIndex <= TOUCH_CNT - 1){
for (int i = 0; i < pointCnt; i++) {
int id = motionEvent.getPointerId(i);
x[id] = (int)motionEvent.getX(i);
y[id] = (int)motionEvent.getY(i);
}
switch (action){
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN:
case MotionEvent.ACTION_MOVE:
isTouch[pointerId] = true;
break;
default:
isTouch[pointerId] = false;
}
}
}
invalidate();
return true;
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<com.exercise.AndroidTouch.MultiTouchView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</LinearLayout>
AndroidTouch.java
package com.exercise.AndroidTouch;
import android.app.Activity;
import android.os.Bundle;
public class AndroidTouch extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
Download the files.
Related article:
- Detect single touch on custom View
- Place two multitouch custom view in a activity
- A Single touch view + a multi touch view in a activity
No comments:
Post a Comment