Tuesday, September 1, 2009

HelloGallery, read picture files from SD, using File ArrayList

It extend from previous exercise, HelloGallery, using Gallery Widget, but read files from SD instead of R.drawable.

Firstly, you have to Create an SD Card to existing AVD and Copying Files to a Disk Image.

All the xml files are same as previous, just keep it no change.

Modify the HelloGallery.java:

package com.exercise.HelloGallery;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;

public class HelloGallery extends Activity {
/** Called when the activity is first created. */
public void onCreate(Bundle savedInstanceState) {

Gallery g = (Gallery) findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this, ReadSDCard()));

g.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent,
View v, int position, long id) {

private List<String> ReadSDCard()
List<String> tFileList = new ArrayList<String>();

//It have to be matched with the directory in SDCard
File f = new File("/sdcard/pictures/");

File[] files=f.listFiles();

for(int i=0; i<files.length; i++)
File file = files[i];
/*It's assumed that all file in the path
are in supported type*/

return tFileList;

public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private List<String> FileList;

public ImageAdapter(Context c, List<String> fList) {
mContext = c;
FileList = fList;
TypedArray a = obtainStyledAttributes(R.styleable.Theme);
mGalleryItemBackground = a.getResourceId(

public int getCount() {
return FileList.size();

public Object getItem(int position) {
return position;

public long getItemId(int position) {
return position;

public View getView(int position, View convertView,
ViewGroup parent) {
ImageView i = new ImageView(mContext);

Bitmap bm = BitmapFactory.decodeFile(

i.setLayoutParams(new Gallery.LayoutParams(150, 100));

return i;

The source file, HelloGaller.java, can be downloaded here.

Next>>File type checking for HelloGallery

- HelloGallery, read picture files from SD, display in ImageView.


Factory Widgets said...
This comment has been removed by the author.
Ray_Haque said...

Thanks for the code! I was looking for a simple way to display images from a specific folder on the SD card, and this does it. I wonder if you could help me out? I know this post is old, but I want an ImageView displayed under the Gallery that will contain a large version of the thumbnail image. So when you click the thumbnail, the full size image loads. Could you provide that in a sample? I realize this was posted a long time ago, but that would really help me out! Thanks again!

Android Er said...

hello Ray_Haque,

Please read HelloGallery, read picture files from SD, display in ImageView.

Ray_Haque said...

Wow, if you did that new Blog entry just for me, I greatly appreciate it. Also, I can see I was going about that all wrong. Thank you!!