Display photos from SD in android.widget.Gallery

The photos in the selected folder will be loaded in a custom adapter to display in Gallery widget.

Modify main.xml, to add <Gallery>.

Modify AndroidGalleryActivity.java.

In order to reduce the resource need to keep the bitmaps, we have to implement a new class PhotoItem hold the path of individual jpg file, and the re-sized bitmap. And a custom BaseAdapter, PhotoBarAdapter, for PhotoItem is implemented for the Gallery.

 
     
 package com.AndroidGallery;

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

import android.R.color;
import android.app.Activity;
import android.app.Dialog;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.webkit.MimeTypeMap;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class AndroidGalleryActivity extends Activity {
 
 Gallery photoBar;
 
 Button buttonOpenDialog;
 Button buttonUp, buttonSelectFolder;
 TextView jpgList;
   
 String KEY_TEXTPSS = "TEXTPSS";
 static final int CUSTOM_DIALOG_ID = 0;
 
 ListView dialog_ListView;
 
 File root;
 File curFolder;
 
 private List fileList = new ArrayList();
 
 class PhotoItem{
  
  String bitmapImageSrc;
  Bitmap bitmapImage = null;
  
  final static int itemWidth = 150;
  final static int itemHeight = 150;
  
  public PhotoItem(String src){
   bitmapImageSrc = src;
   bitmapImage = resize();
  }
  
  public Bitmap getImage(){
   return bitmapImage; 
  }
  
  private Bitmap resize(){
   BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
   bmpFactoryOptions.inJustDecodeBounds = true;

   Bitmap bitmap = BitmapFactory.decodeFile(bitmapImageSrc, bmpFactoryOptions);
   
   int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)itemHeight);
   int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)itemWidth);
   
   if (heightRatio > 1 || widthRatio > 1)
   {
    if (heightRatio > widthRatio){
     bmpFactoryOptions.inSampleSize = heightRatio; 
    } else {
     bmpFactoryOptions.inSampleSize = widthRatio;  
    }  
   }
             
   bmpFactoryOptions.inJustDecodeBounds = false;
   
   bitmap = BitmapFactory.decodeFile(bitmapImageSrc, bmpFactoryOptions);
   
   return bitmap; 
  }
 }
 
 PhotoBarAdapter myPhotoBarAdapter;
 
 public class PhotoBarAdapter extends BaseAdapter {
  
  Context context;
  ArrayList arrayPhotoItem;

  
  PhotoBarAdapter(Context c){
      context = c;
      arrayPhotoItem = new ArrayList();    
  }
  
  public void clear(){
   arrayPhotoItem.clear();
  }
  
  public void addPhotoItem(PhotoItem item){
   arrayPhotoItem.add(item);    
  }
  
  @Override
  public int getCount() {
   return arrayPhotoItem.size();
  }

  @Override
  public Object getItem(int position) {
   return arrayPhotoItem.get(position);
  }

  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   
   LinearLayout viewLayout = new LinearLayout(context);
   viewLayout.setLayoutParams(new Gallery.LayoutParams(200, 200));
   viewLayout.setBackgroundColor(color.background_light);
   
   ImageView imageView;
   imageView = new ImageView(context);
   imageView.setLayoutParams(new Gallery.LayoutParams(150, 150));
   imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
   imageView.setImageBitmap(arrayPhotoItem.get(position).getImage());
   //return imageView;
   
   viewLayout.addView(imageView);
   return viewLayout;
  }
  
 }
 
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  
  photoBar = (Gallery)findViewById(R.id.photobar);
  myPhotoBarAdapter = new PhotoBarAdapter(this);
  photoBar.setAdapter(myPhotoBarAdapter);
   
  jpgList = (TextView)findViewById(R.id.jpglist);
   
  buttonOpenDialog = (Button)findViewById(R.id.opendialog);
  buttonOpenDialog.setOnClickListener(new Button.OnClickListener(){
   @Override
   public void onClick(View arg0) {
    showDialog(CUSTOM_DIALOG_ID); 
   }});
   
  root = new File(Environment
    .getExternalStorageDirectory()
    .getAbsolutePath());
   
  curFolder = root;
  //ListJpgInFolder(curFolder);
  preparePhotoBarInFolder(curFolder);
   
 }
  
 @Override
 protected Dialog onCreateDialog(int id) {
   
  Dialog dialog = null;
   
  switch(id) {
  case CUSTOM_DIALOG_ID:
   dialog = new Dialog(AndroidGalleryActivity.this);
   dialog.setContentView(R.layout.dialoglayout);
   dialog.setTitle("Select JPG");
    
   dialog.setCancelable(true);
   dialog.setCanceledOnTouchOutside(true);
    
   buttonUp = (Button)dialog.findViewById(R.id.up);
   buttonUp.setOnClickListener(new OnClickListener(){
     
    @Override
    public void onClick(View v) {
     // TODO Auto-generated method stub
     ListDir(curFolder.getParentFile()); 
    }});
   
   buttonSelectFolder = (Button)dialog.findViewById(R.id.selectfolder);
   buttonSelectFolder.setOnClickListener(new OnClickListener(){
    
   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    Toast.makeText(AndroidGalleryActivity.this,
      curFolder + " selected",
      Toast.LENGTH_LONG).show();
    dismissDialog(CUSTOM_DIALOG_ID);
    
    //ListJpgInFolder(curFolder);
    preparePhotoBarInFolder(curFolder);

   }});
   
    
   //Prepare ListView in dialog
   dialog_ListView = (ListView)dialog.findViewById(R.id.dialoglist);
    
   dialog_ListView.setOnItemClickListener(new OnItemClickListener(){
     
    @Override
    public void onItemClick(AdapterView parent, View view,
      int position, long id) {
     File selected = new File(fileList.get(position));
     if(selected.isDirectory()){
      ListDir(selected);  
     } 
    }});
        
   break;
  }
  return dialog; 
 }
  
 @Override
 protected void onPrepareDialog(int id, Dialog dialog, Bundle bundle) {
  // TODO Auto-generated method stub
  super.onPrepareDialog(id, dialog, bundle);
   
  switch(id) {
  case CUSTOM_DIALOG_ID:
   ListDir(curFolder);
   
   break; 
  } 
 }
  
 void ListDir(File f){
   
  if(f.equals(root)){
   buttonUp.setEnabled(false); 
  }else{
   buttonUp.setEnabled(true); 
  }
   
  curFolder = f;
  buttonSelectFolder.setText("Select Folder " + curFolder);
   
  File[] files = f.listFiles();
  fileList.clear();
  for (File file : files){
   if(file.isDirectory()){
    fileList.add(file.getPath()); 
   }else{
    Uri selectedUri = Uri.fromFile(file);
    String fileExtension
     = MimeTypeMap.getFileExtensionFromUrl(selectedUri.toString());
    if(fileExtension.equalsIgnoreCase("jpg")){
     fileList.add(file.getName()); 
    } 
   } 
  }
   
  ArrayAdapter directoryList
   = new ArrayAdapter(this,
     android.R.layout.simple_list_item_1, fileList);
  dialog_ListView.setAdapter(directoryList); 
 }
 
 private void preparePhotoBarInFolder(File folder){
  
  String jpgs = "JPG fiels in folder " + folder.getAbsolutePath() + "\n\n";
  
  File[] files = folder.listFiles();
  
  myPhotoBarAdapter.clear();
  
  for (File file : files){
   if(!file.isDirectory()){
    Uri selectedUri = Uri.fromFile(file);
    String fileExtension
     = MimeTypeMap.getFileExtensionFromUrl(selectedUri.toString());
    if(fileExtension.equalsIgnoreCase("jpg")){
     jpgs += file.getAbsolutePath() + "\n";
     
     PhotoItem pItem = new PhotoItem(file.getAbsolutePath());
     myPhotoBarAdapter.addPhotoItem(pItem);
     
     myPhotoBarAdapter.notifyDataSetChanged();
    }  
   }  
  }
  jpgList.setText(jpgs); 
 }
  
}