Dr. Ramkumar Lakshminarayanan article published in Tamil Computer Magazine. The content is about Single Touch event view in Android.

1. ݇†ó£Œ´ Þ¡Á ÜŠO«èê¡ à¼
õ£‚°õF™ ðô õ÷˜„Cè¬÷ ªðŸÁ
àœ÷ù. ð£¬îò âv®«è ðò¡ð£´ 4.0
Ýè àœ÷¶.
Ýù£™ ªð¼‹ð£ô£ù ªê™ «ðCèœ
âv®«è 2.0 -ä ðò¡ð´ˆ¶A¡øù. ݇†
󣌴 4.0 -ä Icecream Sandwich â¡Á ܬö‚
Aø£˜èœ. ݇†ó£Œ´ 2.0 õ¬èèœ Ginger
bread â¡Á‹ ݇†ó£Œ´ 3.0 õ¬èèœ Honey
comb â¡Á‹ ܬö‚èŠð´Aø¶. ݇†
󣌴 F¬óJ™ õ¬ó»‹ ÜŠO«èê¬ù ºîL™
𣘊«ð£‹.
File>New>Android Project H¡ù˜ Project
Name â¡ðF™ Single Touch View â¡Á
ªè£´‚è «õ‡´‹. Build Target â¡ðF™
݇†ó£Œ´ 4.0.3 â¡ðî¬ù «î˜‰ªî´‚è
«õ‡´‹. Ü´ˆî F¬óJ™ ÜŠO«èê¡ ðŸPò
îèõ™è¬÷ ªè£´‚è «õ‡´‹. ÞF™ Package
Name ªè£´Šð¶ ÜõCò‹. Þ‰î ꣡P™
ram.com.singletouchview â¡Á ªè£´‚èŠ
ð†´œ÷¶. (ðì‹-1) H¡ù˜ Finesh ð†ì¬ù
AO‚ ªêŒò «õ‡´‹.
package ram.com.singletouchview;
import android.content.Context;
import android.view.View;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
public class SingleTouchEventView
extends View {
private Paint paint = new Paint();
private Path path = new Path();
public SingleTouchEventView(Context
context) {
super(context);
// TODO Auto-generated
constructor stub
paint.setAntiAlias(true);
paint.setStrokeWidth(6f);
paint.setColor(Color.WHITE);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
}
@Override
protected void onDraw(Canvas canvas)
{
canvas.drawPath(path, paint);
}
@Override
public boolean
onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(eventX, eventY);
return true;
case MotionEvent.ACTION_MOVE:
path.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
// nothing to do
break;
default:
return false;
}
// Schedules a repaint.
invalidate();
return true;
}
}
VI Component Ýù MÎ Íô‹ ðòù£÷Kì
I¼‰¶ F¬óJ™ ªî£´‹ îèõ™è¬÷ ªðø
ô£‹. F¬óJ™ ªî£´‹ º¬øJ¬ù ªêò™
ð´ˆî Motion Event Class -ä ðò¡ð´ˆî «õ‡
´‹. Þ‰î ÜŠO«èêQ™ ðò¡ð´ˆîŠð´‹.
ߪõ¡†´èœ..
MotionEvent.ACTION_DOWN, MotionEvent.
ACTION-MOVE, MotionEvent.ACTION-UP, Motion
Event.ACTION-OUTSIDE Ý°‹.
F¬óJ™ ¹Fî£è ªî£´‹«ð£¶ Motion
Event.ACTION-DOWN ï¬ìªðÁ‹. F¬óJ™
Mó™ ï輋«ð£¶ MotionEvent. ACTION-MOVE
ï¬ìªðÁ‹, F¬óJ™ Mó™ «ñ™«ï£‚A ï¬ì
ªðÁ‹«ð£¶, MotionEvent. ACTION-UP ï¬ì
ªðÁ‹ Mó™ F¬óJL¼‰¶ Mô°‹«ð£¶
MotionEvent.ACTION-OUTSIDE ï¬ìªðÁ‹.
CƒAœ ì„ ßªõ¡†
Mξ‚è£ù Gó™!
Gó™-1

2. Ý¡†ó£Œ´ -2
Þ󣋰ñ£˜ ªô†²Iï£ó£òí¡
18
package ram.com.singletouchview;
import android.app.Activity;
import android.os.Bundle;
public class SingletouchviewActivity
extends Activity {
/** Called when the activity is first
created. */
@Override
public void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
setContentView(new
SingleTouchEventView(this));
}
}
View (this)); â¡Á ñ£Ÿø «õ‡´‹. ÞîŸè£ù
Gó™-2™ ªè£´‚èŠð†´œ÷¶.
Ü´ˆ¶, ç¬ðL¬ù «î˜‰ªî´ˆ¶ Run
As>Android Application â¡Á ªè£´‚è «õ‡
´‹. H¡ù˜ ⺫ô†ì˜ F¬óJ™ ñ¾v
Íô‹ õ¬óò º®»‹. (ðì‹-1) ªê™«ðCJ™
¬èJù£™ F¬ó «î£¡Á‹ «ð£¶ ܃«è
õ¬óòŠð´‹. ªî£´‹ º¬øJ™ ðô ªêò™
è¬÷ ݇†ó£Œ®™ ¬èò£÷ô£‹.
ºîL™ Single Touch Event View â¡ðîŸ
è£ù A÷£vC¬ù à¼õ£‚è «õ‡´‹. Single
TouchEventView MŸè£ù Gó™, Gó™ -1™
ªè£´‚èŠð†´œ÷¶. Single Touch Event View
-™ View Extend ªêŒòŠð†´œ÷¶.
F¬óJ™ ªî£´‹«ð£¶ ãŸð´‹ õ¬óî™
âšõ£Á Þ¼‚è «õ‡´‹ â¡ðî¬ù Single
Touch Event View (Content Context) {} Íô‹
õ¬óî™ F¬óJ™ ï¬ìªðÁAø¶. ªî£´õ
ãŸð ñ£Ÿøƒè¬÷ ÜPò OnTouchEvent ðò¡
ð´Aø¶. get Action () Ü™ô¶ MotionEvent.
ACTION-DOWN ï¬ìªðŸÁœ÷î£, Ü™ô¶
MotionEvent. ACTION-MOVE ï¬ìªðŸÁœ÷î£,
â¡ð ãŸð OnDraw() ñ£Ÿøƒè¬÷ F¬ó
J™ ܬñ‚°‹.
Ü´ˆîî£è, SingletouchviewActivity ç¬ðL™
ñ£Ÿøƒèœ ªêŒò «õ‡´‹. SetContentView
M¬ù SetContentView(new Single Touch Event - ªî£ì¼‹
Gó™-2
ðì‹-1