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

1. ݇†ó£Œ®™ ðìƒè¬÷ ¬èò£À
õ ðô º¬øèœ àœ÷ù. ÜõŸ
Áœ å¼ º¬ø «èôK (Gallery) ðò¡ð´ˆ¶
õ‹.
ºîL™ «èôK â¡ø Šó£ªü‚†®¬ù
à¼õ£‚è «õ‡´‹. Þ‰î Šó£ªü‚†®¡
«ï£‚è‹ å¼ Cô ðìƒè¬÷ õK¬êò£è
F¬óJ™ 裇Hˆ¶, ãî£õ¶ ðìˆF¬ù
AO‚ ªêŒî¾ì¡ F¬óJ™ îèõL¬ù
裇HŠð«îò£°‹. ÜŠO«èû¡ â‚OŠv
ªè£‡´ à¼õ£‚°A«ø£‹.
â‚OŠvC™ à¼õ£‚èŠð´‹ ÜŠO«èê¡
è¬÷ å¼ å˜‚v«ðC™ (Work Space) «êIˆ¶
¬õ‚°‹. â¡Â¬ìò ÜŠO«èê¡èœ âù¶
èEQJ™ C:usersmeeraneelaworkspace
â¡ø ç«ð£™ìK™ «êI‚èŠð´A¡øù.
(ðì‹-1). à¼õ£‚èŠð´‹ Šó£ªü‚†´èœ
ç«ð£™ìó£è «êI‚èŠð´‹. Þƒ° Gallery
â¡ø ç«ð£™ì˜ Þ¼Šðî¬ù è£íô£‹.
Gallery/res â¡ø ç«ð£™ìK¬ù à¼õ£‚A
Sample.jpg, Sample2.jpg,sample3.jpg,sample4.
jpg,sample5.jpg,sample6.jpg ñŸÁ‹ Sample
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<Gallery
android:id="@+id/gallery"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
ðì‹-1
ðì‹-2
Gó™-1
ðìƒè¬÷
¬èò£À‹
«èôK!

2. Ý¡†ó£Œ´ -2
Þ󣋰ñ£˜ ªô†²Iï£ó£òí¡
15
7.jpg â¡Á ªðò¼¬ìò ðìƒè¬÷ «êIˆ
F´ƒèœ. (ðì‹-2)
Ü´ˆîî£è «èôK ÝŠªü‚†®¬ù main.
xml -™ ðò¡ð´ˆî «õ‡´‹. main.xml-Ÿ
è£ù¶ Gó™ -1-™ àœ÷¶ «ð£¡Á Þ¼‚°‹.
Ü´ˆîî£è Šó£ªü‚† à¼õ£‚èŠð†ì
¾ì¡ «î£¡P»œ÷ Gallery Activity.java
ç¬ðL™ àœ÷ OnCreate ªñˆî®™ Gó™-2™
àœ÷¶ «ð£¡Á Gó™è¬÷ Þ¬í‚è «õ‡
´‹.
ºîL™ main.xml-™ àœ÷ «ôܾ†®¬ù
Content View â¡Á ܬñ‚A«ø£‹.
Ü´ˆîî£è «èôK ÝŠªü‚†®¬ù find
viewById(R.id.gallery) ðò¡ð´ˆF «ôܾ†´
ì¡ Þ¬íˆFì «õ‡´‹. «èôKJ™ ðò¡
𴈶õîŸè£è BaseAdapter å¡P¬ù à¼
õ£‚è «ð£A«ø£‹. Üî¡ ªðò˜ Image
Adapter â¡ð‹.
Ü´ˆîî£è «èôKJ™ SetOnItemClick
Listener ðò¡ð´ˆF AO‚ ªêŒõîù£™
îèõ™ F¬óJ™ «î£¡Áñ£Á ܬñˆ¶œ
«÷£‹. îèõ™ F¬óJ™ 裇H‚è Toast ðò¡
ð´ˆîŠð†´œ÷¶.
Ü´ˆîî£è «èôKJ™ ðò¡ð´ˆîŠð´‹
v¬ìL¬ù (Style) °PŠH´õîŸè£è attrs.
xml â¡ø Xml ç¬ðL¬ù ðò¡ð´ˆî «ð£A
«ø£‹. attrs.xml-Ÿè£ù Gó™ -3™ ªè£´‚
Gallery gallery = (Gallery)findViewById(R.id.gallery);
gallery.setAdapter(new ImageAdapter(this));
gallery.setOnItemClickListener(new onItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View v, int position,
long id) {
// TODO Auto-generated method stub
Toast.makeText(GalleryActivity.this,""+ position, Toast.LENGTH_SHORT).show();
}} );
<?xml version="1.0" encoding="utf-
8"?>
<resources>
<declare-styleable
name="HelloGallery">
<attr
name="android:galleryItemBackground
"/>
</declare-styleable>
</resources>
èŠð†´œ÷¶. <attr> âLªñ¡† Íô‹
v“L android.gallery ItemBack ground
â¡Á °PŠH†´œ«÷£‹.
Ü´ˆîî£è ImageAdapter.java â¡ø
ç¬ðL¬ù à¼õ£‚è «õ‡´‹. à¼õ£‚èŠ
𴋫𣶠«ðv Ü죊ìK¬ù (Base
Adapter) Extend ªêŒò «õ‡´‹. (Gó™-4)
Array- J¬ù ªè£‡´ drawable Folder- ™
ެ특 ãŸð´ˆî «õ‡´‹. Ü´ˆîî£è
Class Constructor ðò¡ð´ˆîŠð†´œ÷¶.
Gó™-2
Gó™-3
ðì‹-3
ðì‹-4

3. package ram.com.gallery;
import android.content.Context;
import android.content.res.TypedArray;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
public class ImageAdapter extends
BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private Integer[] mImageIds ={
R.drawable.sample1,
R.drawable.sample2,
R.drawable.sample3,
R.drawable.sample4,
R.drawable.sample5,
R.drawable.sample6,
R.drawable.sample7
};
public ImageAdapter(Context c){
mContext = c;
TypedArray attr =
mContext.obtainStyledAttributes(R.styleab
le.HelloGallery);
mGalleryItemBackground =
attr.getResourceId(R.styleable.HelloGaller
y_android_galleryItemBackground, 0);
attr.recycle();
}
@Override
public int getCount() {
// TODO Auto-generated method
stub
return mImageIds.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method
stub
return mImageIds[position];
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method
stub
return mImageIds[position];
}
@Override
public View getView(int position, View
convertView, ViewGroup parent) {
// TODO Auto-generated method
stub
ImageView imageView = new
ImageView(mContext);
imageView.setImageResource(mImageIds
[position]);
imageView.setLayoutParams(new
Gallery.LayoutParams(150,100));
imageView.setScaleType(ImageView.Scal
eType.FIT_XY);
imageView.setBackgroundResource(mGall
eryItemBackground);
return imageView;
}
}
Gó™-4
Þƒ° Þ«ñx Ü죊켂
è£ù Context õ¬óòÁ‚èŠ
ð†´œ÷¶. Ü´ˆîî£è style
able resource â¡ðî¬ù attr
â¡ø çd™´ (Field) Íô‹
°PŠHìŠ ð†´œ÷¶.
Constructor- ¡ º®M™ Typed
Array -J¬ù ®¬õv e‡´‹
ðò¡ð´ˆîô£‹ â¡ðîŸè£è
recycle() ðò¡ð´ˆîŠð†
´œ÷¶.
Þ«ñT¬ù «èôK»ì¡
ެ특 ãŸð´ˆ¶õ
getCount(),getItem() ñŸÁ‹
getIte mId() ªñˆî†èœ ðò¡
ð´ˆîŠð†´œ÷¶. getview
ªñˆî† Íô‹ ContextMember
Íô‹ Þ«ñx MÎ à¼õ£‚èŠ
ð†´œ÷¶.
Þ«ñx MÎMŸ° drawble-
L™ àœ÷ ðìƒèÀì¡
ެ특 ãŸð´ˆîŠð†´œ
֦.
imageView.setImageResourc
e(mImageIds [position];
Þ«ñx MÎM¡ c÷ ñŸÁ‹
ÜèôˆF¬ù Gallery.Layout
params Íô‹ °PŠH†´œ
«÷£‹.

4. ðì‹-6ðì‹-5
- ªî£ì¼‹
i m a g e V i e w . S e t L a y o u t
Params (new Gallery. Layout
Params(150,100);
Þî¬ù «ð£¡«ø,
SetScaleType ñŸÁ‹ SetBack
groundResource ðò¡ð´ˆîŠ
ð†´œ÷¶. ÜŠO«èê¬ù
ªêò™ð´ˆ¶õ ºîL™
Project-Build Project â¡ð
î¬ù AO‚ ªêŒò «õ‡´‹.
H¬öèœ ã«î‹ Þ¼‰î£™
Þ‰î ªêò™ Íô‹ ÜP‰¶
ªè£œ÷ô£‹.
Ü´ˆîî£è «èôK â¡ø
Šó£ªü‚†®¬ù «î˜¾
ªêŒ¶ Run As>Android Appli
cation â¡Á AO‚ ªêŒò
«õ‡´‹. (ðì‹-3)
Run As> Android Application
â¡ðî¬ù «î˜¾ ªêŒî¾ì¡
ðì‹-4™ àœ÷¶ «ð£¡Á
«î£¡Á‹. «î¬õò£ù âº
«ô†ìK¬ù«ò£ (Emulator)
Ü™ô¶ ®¬õC¬ù«ò£
«î˜‰ ªî´ˆ¶ ªè£œ÷ô£‹.
«èôK ÜŠO«èê¡ ðì‹-5™
àœ÷¶ «ð£¡Á F¬óJ™
«î£¡Á‹ ðìˆF¬ù
®¬õvªî£´F¬óJ™ªî£†
죙 ðìˆF¡ ⇠F¬óJ™
«î£¡Á‹. (ðì‹-6)