Dr. Ramkumar Lakshminarayanan article published in Tamil Computer Magazine. The content is about creating Android Animation Application.

1. ݇†ó£Œ´ ÜQ«ñû¬ù
à¼õ£‚°õ ðô API
è¬÷ õöƒA»œ÷¶. Þî¡ Íô‹
2® ñŸÁ‹ 3® à¼õƒè¬÷ à¼
õ£‚è º®»‹. ÜQ«ñû¬ù
݇†ó£Œ´ 3.0 -™ Þ¼‰¶
Šó£Šð˜†® ÜQ«ñû¡ ñŸÁ‹
MÎ ÜQ«ñû¡ â¡Á Þó‡´
º¬øè¬÷ õöƒA»œ÷¶. Šó£Š
ð†® ÜQ«ñûQ™ MÎ ÜQ
«ñû¬ù‚ 裆®½‹ ÜFè ðò¡
𣴠º¬ø Þ¼Šð Šó£Š
𘮠ÜQ«ñû¬ù«ò ÜFè‹
«ð˜ ðò¡ð´ˆ¶Aø£˜èœ. Draw
able Resource-™ àœ÷ ðìƒ
è¬÷ ªè£‡´‹, ðìƒè¬÷
å¡ø¡ H¡ å¡ø£è 裇Hˆ¶
ÜQ«ñû¬ù à¼õ£‚èô£‹.
âO¬ñò£ù ÜQ«ñû¡ å¡P¬ù à¼
õ£‚°‹ º¬øJ¬ù 𣘊«ð£‹. ¹Fò Šó£
ü‚† å¡P¬ù ªî£ìƒA Üî¡ ªðò¬ó
݇†ó£Œ®™ ÜQ«ñû¡
animation text âù ªðòK´«õ£‹.
Þ‰î ꣡P™ main xme-™ â‰î
Mî ñ£Ÿøƒè¬÷»‹ ªêŒò «ð£õ
F™¬ô. on draw º¬ø Íô‹ õ†ì
ñ£è îèõ™ ²Ÿø «õ‡´‹ â¡ð¬î
°P‚è ðò¡ð´Aø¶. Þƒ° canvas
J¬ù Parameter Ýè ªè£´‚è
«õ‡´‹. «è¡õ£v â¡ð¶ ®ó£
ªñˆî®™ Þ¼‰¶ (Draw) ãŸð´‹
call è¬÷ ¬èò£÷ ðò¡ð´Aø¶.
®ó£M¬ù ðò¡ð´ˆ¶õ 4
裋«ð£ù†èœ (Componets) ðò¡
ð´Aø¶.ܬõ H‚ê™è¬÷¬èò£÷
H†«ñŠ ®ó£‚è¬÷ ¬èò£÷
canvas âŠð® õ¬óò «õ‡´‹,
recet, path, text,bitmap ñŸÁ‹ paint
(õ¬óîL¡ õ‡íƒèœ ñŸÁ‹ v¬ì™
è¬÷ °P‚è)
Þ‰î ꣡P™ ⿈¶è¬÷ circular path-™
ðò¡ð´ˆîŠð´‹. on draw MŸè£ù Gó™-1™
ªè£´‚èŠð†´œ÷¶.
Path circle = new Path();
int centerX = canvas.getWidth() / 2;
int centerY = canvas.getHeight() / 2;
int r = Math.min(centerX, centerY);
circle.addCircle(centerX, centerY, r,
Direction.CW);
Paint paint = new Paint();
paint.setColor(Color.GREEN);
paint.setTextSize(30);
paint.setAntiAlias(true);
canvas.drawTextOnPath(AnimatedTxt, circle,
0, 30, paint);
private void createAnim(Canvas canvas) {
rotateAnim = new RotateAnimation(0,
360, canvas.getWidth() / 2,
canvas.getHeight() / 2);
rotateAnim.setRepeatMode(Animation.REVER
SE);
rotateAnim.setRepeatCount(Animation.INFINI
TE);
rotateAnim.setDuration(10000L);
rotateAnim.setInterpolator(new
AccelerateDecelerateInterpolator());
startAnimation(rotateAnim);
Gó™-1
Gó™-2
ðì‹-1
ðì‹-2
ðì‹-3

2. Ý¡†ó£Œ´ -2
Þ󣋰ñ£˜ ªô†²Iï£ó£òí¡
20
ÜQ«ñû¬ù õ†ìñ£è ªêò™ð´ˆFì,
create animation ªñˆî† ðò¡ð´ˆîŠð´‹.
rotate animation Íô‹ ¹Fò rotate animation
à¼õ£‚è «õ‡´‹. rotation Ýù¶ x,ypane-™
ãŸð´‹. â‰î ¹œO¬ò ªè£‡´ ÜQ«ñû¡
ãŸðìô£‹ â¡ðî¬ù °PŠHìô£‹. 0,0 â¡
ð¶ Þì¶ ð‚èˆF™ àœ÷ ºî™ ¹œO«ò
Ý°‹. â‰î ¹œO¬ò»‹ °PŠHìM™¬ô
â¡ø£™ 0,0 J¬ù ¹œOò£è ªè£‡´ ÜQ
«ñû¡ à¼õ£‚èŠð´‹. AK«ò† ÜQ«ñû
QŸè£ù Gó™ 2-™ ªè£´‚èŠð†´œ÷¶.
Þ‰î ꣡P™ ªìv‚†®Ÿè£ù îèõL¬ù
package com.ram.animationtext;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.os.Bundle;
import android.view.View;
import
android.view.animation.AccelerateDecelerateIn
terpolator;
import android.view.animation.Animation;
import
android.view.animation.RotateAnimation;
public class AnimationtextActivity extends
Activity {
@Override
public void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new
GraphicsView(this));
}
private static class GraphicsView extends
View {
private static final String AnimatedTxt
=
"This Sample Program Shows,
Aniamtion Using Path. This is very simple and
easy to understand.";
private Animation rotateAnim;
public GraphicsView(Context context)
{
super(context);
}
private void createAnim(Canvas
canvas) {
rotateAnim = new
RotateAnimation(0, 360, canvas.getWidth() / 2,
canvas.getHeight() / 2);
rotateAnim.setRepeatMode(Animation.REVERS
E);
rotateAnim.setRepeatCount(Animation.INFINIT
E);
rotateAnim.setDuration(10000L);
rotateAnim.setInterpolator(new
AccelerateDecelerateInterpolator());
startAnimation(rotateAnim);
}
@Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
// creates the animation the first
time
if (rotateAnim == null) {
createAnim(canvas);
}
Path circle = new Path();
int centerX = canvas.getWidth() /
2;
int centerY = canvas.getHeight() /
2;
int r = Math.min(centerX,
centerY);
circle.addCircle(centerX, centerY,
r, Direction.CW);
Paint paint = new Paint();
paint.setColor(Color.GREEN);
paint.setTextSize(30);
paint.setAntiAlias(true);
canvas.drawTextOnPath(AnimatedTxt, circle, 0,
30, paint);
}
}
animated text â¡ø ñ£PLJ™ ªè£´ˆ¶œ
«÷£‹. Gó™-3-™ ªì‚v† ÜQ«ñûQŸè£ù
º¿ Gó¬ô»‹ ªè£´ˆ¶œ«÷£‹. Þ‰î
GóL¬ù 苬ð™ (Compile) ªêŒ¶ ó¡ ªêŒ
Gó™-3

3. package ram.com.graphiceffect;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ComposePathEffect;
import android.graphics.CornerPathEffect;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathDashPathEffect;
import android.graphics.PathEffect;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
public class GraphiceffectexampleActivity
extends Activity {
/** Called when the activity is first created.
*/
@Override
protected void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new SampleView(this));
}
private static class SampleView extends
View {
private Paint mPaint;
private Path mPath;
private PathEffect[] mEffects;
private int[] mColors;
private float mPhase;
private static PathEffect makeDash(float
phase) {
return new DashPathEffect(new
float[] { 15, 5, 8, 5 }, phase);
}
private static void
makeEffects(PathEffect[] e, float phase) {
e[0] = null; // no effect
e[1] = new CornerPathEffect(10);
e[2] = new DashPathEffect(new
float[] {10, 5, 5, 5}, phase);
e[3] = new
PathDashPathEffect(makePathDash(), 12,
phase,
PathDashPathEffect.Style.ROTATE);
e[4] = new ComposePathEffect(e[2],
e[1]);
e[5] = new ComposePathEffect(e[3],
e[1]);
}
public SampleView(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
mPaint = new
Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(6);
mPath = makeFollowPath();
mEffects = new PathEffect[6];
mColors = new int[] { Color.BLACK,
Color.RED, Color.BLUE,
Color.GREEN,
Color.MAGENTA, Color.BLACK
};
}
@Override protected void
onDraw(Canvas canvas) {
canvas.drawColor(Color.WHITE);
RectF bounds = new RectF();
mPath.computeBounds(bounds, false);
canvas.translate(10 - bounds.left, 10 -
bounds.top);
makeEffects(mEffects, mPhase);
mPhase += 1;
invalidate();
for (int i = 0; i < mEffects.length;
i++) {
mPaint.setPathEffect(mEffects[i]);
mPaint.setColor(mColors[i]);
canvas.drawPath(mPath, mPaint);
canvas.translate(0, 28);
}
}
@Override public boolean onKeyDown(int
keyCode, KeyEvent event) {
switch (keyCode) {
case
KeyEvent.KEYCODE_DPAD_CENTER:
mPath = makeFollowPath();
return true;
}
return super.onKeyDown(keyCode,
event);
}
private static Path makeFollowPath() {
Path p = new Path();
p.moveTo(0, 0);
for (int i = 1; i <= 15; i++) {
p.lineTo(i*20, (float)Math.random()
* 35);
}
return p;
}
private static Path makePathDash() {
Path p = new Path();
p.moveTo(4, 0);
p.lineTo(0, -4);
p.lineTo(8, -4);
p.lineTo(12, 0);
p.lineTo(8, 4);
p.lineTo(0, 4);
return p;
}
}
} Gó™-4

4. - ªî£ì¼‹
 ðì‹ 1-™ àœ÷¶ «ð£¡ø ÜQ«ñû¡
«î£¡Á‹.
Ü´ˆî ꣡ø£è Aó£çH‚ â炆 J¬ù
à¼õ£‚°‹ º¬øJ¬ùŠ 𣘊«ð£‹. path
effect A÷£ê£ù¶ ݇†ó£Œ´ Aó£çH‚C¡
A÷£vC¬ù Ü®Šð¬ìò£è‚ ªè£‡´œ÷¶.
«ðˆ âçªð‚†®¡ «ïó®ò£ù êŠ A÷£vèœ
compose path effect ,corner path effect, dash
path effect, dis create path effect, path dash path
effect ñŸÁ‹ sum path effect «ð£¡ø¬õò£°‹.
¹Fò Šó£ªü‚† å¡P¬ù ªî£ìƒA Üî¡
ªðòK¬ù graphiceffectexample âù ªðòK´ƒ
èœ. Þ‰î ꣡P½‹ main xme-™ â‰î ñ£Ÿø
º‹ ªêŒòŠ«ð£õF™¬ô. graphiceffectexample
activity -J¬ù extend ªêŒ»ñ£Á à¼õ£‚è
«õ‡´‹. Ü´ˆîî£è sample view â¡ø extend
private static class J¬ù à¼õ£‚A MÎM¬ù
extend ªêŒ»ñ£Á à¼õ£‚è «õ‡´‹. on
create º¬øJ™ set content view(new sample
view(this) â¡Á ªè£´ˆ¶ sample view
-M¬ù ðò¡ð´ˆ¶ñ£Á à¼õ£‚è «õ‡´‹.
sample view M™ paint path ñŸÁ‹ path effect
è¬÷ ðò¡ð´ˆF ÜõŸPŸè£ù ñFŠ¹è¬÷
ªè£´‚è «õ‡´‹. make effect º¬ø Íô‹
patheffect-¡ ܬñŠH¬ù °PŠHì «õ‡´‹.
on draw method Íô‹ canvasJ¬ù ðò¡
ð´ˆF ÜQ«ñû¡ ªêò™ð£†´ º¬øJ¬ù
°PŠHì «õ‡´‹ Þî¬ù îMó on key down
eventJ¬ù ¬èò£À‹ º¬ø»‹ ðò¡ð´ˆîŠ
ð†´œ÷¶. on key down-™ KEY CODE-DPAD-
CENTER J¬ù Ü¿ˆFù£™ path J¬ù ñ£ŸP
ܬñ‚°‹ Gó™ ðò¡ð´ˆîŠ ð†´œ÷¶.KEY
CODE-DPAD-CENTER ⃰ Þ¼‚°‹ â¡ðî¬ù
ðì‹ 2™ 裇H‚èŠ ð†´œ÷¶. Aó£çH‚v
âçªð‚†®Ÿè£ù Gó™4-™ 裇H‚èŠð†´œ
÷¶. ÜŠO«èû¡ ó¡ ªêŒî¾ì¡ ðì‹ 2
ñŸÁ‹ 3-™ àœ÷¶ «ð£¡Á «î£¡Á‹.