android 图片浏览器 APP 源码

          该应用通过ImageSwitcher和Gallery控件，来显示手机sdcard中的图片。功能还不完善，目前仅支持，查看详细和删除，功能。仅供初学者学习。
    整个的工程的源码，在这里:http://download.csdn.net/detail/mci2004/4293560。由于我没有做过android的APP开发，所以这个应用是我参考了大量晚上代码和项目的结果。这里要补充一下，在我的项目中，有一个Debug.java文件，这个是开发初期调试用的，后来没用到了，希望不会给大家带来困扰。
    下面贴出部分源码：

 

//应用的入口   

package com.alan.android;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.os.Environment;
import android.text.format.Formatter;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.Gallery.LayoutParams;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ViewSwitcher.ViewFactory;

/**
 * @author Alan
 *
 */
public class ImageViewerActivity extends Activity implements ViewFactory, OnItemSelectedListener {

	private ImageSwitcher mImgSwitcher;
	
	private Gallery mGallery;
	
	private ImageAdapter adapter;
	
	private ArrayList<String> mImgPathList;
	
	private static boolean deleteHappen = false;

	//sdcard Path
	private String mSdcardPath;
	
	//cache for the Bitmap res
	private HashMap<Integer, Bitmap> imgCache = new HashMap<Integer, Bitmap>();
	
	private static final String LOG_TAG="ImageViewer";
	
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        mImgPathList = new ArrayList<String>();
        mSdcardPath  = Environment.getExternalStorageDirectory().toString(); 
        
        saveImagePathToList(mImgPathList, mSdcardPath);
        
        //set ImageSwitcher
        mImgSwitcher = (ImageSwitcher)findViewById(R.id.imgswitcher);
        mImgSwitcher.setFactory(this);
        mImgSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,android.R.anim.fade_in));
        mImgSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,android.R.anim.fade_out)); 

        //set Gallery
        mGallery = (Gallery)findViewById(R.id.imgallery);
        adapter = new ImageAdapter(this, mImgPathList);
        mGallery.setAdapter(adapter);
        mGallery.setOnItemSelectedListener(this);
        mGallery.setOnItemLongClickListener(new OnItemLongClickListener(){

			public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
					final int position, long id) {
				// TODO Auto-generated method stub
				AlertDialog.Builder build = new Builder(ImageViewerActivity.this);
				build.setTitle("ä½ æƒ³æ‰§è¡Œä¸‹åˆ—å“ªä¸ªæ“ä½œï¼Ÿ")
				.setPositiveButton("åˆ é™¤é€‰ä¸­æ–‡ä»¶", new OnClickListener(){

					public void onClick(DialogInterface dialog, int which) {
						// TODO Auto-generated method stub
						onDelBtnDown(position);
					}				
				})
				.setNegativeButton("详细信息", new OnClickListener(){

					public void onClick(DialogInterface dialog, int which) {
						// TODO Auto-generated method stub
						onDetailBtnDown(position);
					}					
				});
				build.create().show();
				return false;
			}
        	
        });
    }
    
    //button down callbacks
	private void onDetailBtnDown(int pos) {
		// TODO Auto-generated method stub
		final View d = View.inflate(this, R.layout.detailsview,null);
		
		//Thumbnail View
		ImageView imageView = (ImageView) d.findViewById(
                R.id.details_thumbnail_image);
		Bitmap bm = BitmapFactory.decodeFile(mImgPathList.get(pos));
		imageView.setImageBitmap(bm);
		
		//Text View of Image Title
		TextView txTitle = (TextView) d.findViewById(R.id.details_image_title);
		txTitle.setText(geTitle(pos));
		
		//the picture resolution value
		int width = bm.getWidth();
		int height = bm.getHeight();
		String pictureSize = width + "*" + height;
		setDetailsValue(d, pictureSize, R.id.details_resolution_value);
		
		//the picture size
		String size = Formatter.formatFileSize(this, height*width);
		setDetailsValue(d, size, R.id.details_file_size_value);
		
		//get date
		String value = null;
		File f = new File(mImgPathList.get(pos));
		long lastMod = f.lastModified();
		if (lastMod != 0) {
            Date date = new Date(lastMod);
            SimpleDateFormat dateFormat = new SimpleDateFormat();
            value = dateFormat.format(date);
        }
        if (value != null) {
            setDetailsValue(d, value, R.id.details_date_taken_value);
        } else {
            hideDetailsRow(d, R.id.details_date_taken_row);
        }
		
		AlertDialog.Builder build = new Builder(ImageViewerActivity.this);
		build.setTitle("详细信息")
		.setView(d)
		.show();
		
	}
	
	private static void setDetailsValue(View d, String text, int valueId) {
        ((TextView) d.findViewById(valueId)).setText(text);
    }

    private static void hideDetailsRow(View d, int rowId) {
        d.findViewById(rowId).setVisibility(View.GONE);
    }

	
	private String geTitle(int pos){
		
		String title = mImgPathList.get(pos);
		int last_s = title.lastIndexOf("/");
		int last_l = title.lastIndexOf(".");
		
		title = title.substring(last_s + 1, last_l);
		return title;
		
	}
	

	private void onDelBtnDown(int pos) {
		// TODO Auto-generated method stub
		deleteHappen = true;
		Log.d(LOG_TAG,"the pos will deleted is " + pos);		
		File current = new File(mImgPathList.get(pos));
		current.delete();
		
		mImgPathList.remove(pos);		
		adapter.notifyDataSetChanged();
		mGallery.setAdapter(adapter);
		
		if(pos == 0 && mImgPathList.size() == 0){
			mImgSwitcher.setImageDrawable(null);
			Toast.makeText(this, "The Picture isn't exist, or Deleted",
                    Toast.LENGTH_SHORT).show();
		}
	}	
    
    //get image path recursively
	private void saveImagePathToList(ArrayList<String> list, String filePath) {
		// TODO Auto-generated method stub
		
		File mFile = new File(filePath);
		File[] listFile = mFile.listFiles();
		
		if(listFile != null){
			
			for(int i = 0 ; i < listFile.length ; i++){
				
				File file = listFile[i];
				
				if(isAnImageFile(file.getAbsolutePath())){
					list.add(file.getAbsolutePath());
				}else if(file.isDirectory() && !file.getAbsolutePath().contains("DCIM")){
					//get image path recursively
					this.saveImagePathToList(mImgPathList, file.getAbsolutePath());
				}
				continue;
			}
			
		}
	}
	
	//check the fils's suffix and tell whether it's an image
	private boolean isAnImageFile(String fileName){
		
		String fileNameLowerCase = fileName.toLowerCase();
		
		if(fileNameLowerCase.endsWith("jpg") || fileNameLowerCase.endsWith("gif") 
				|| fileNameLowerCase.endsWith("bmp") || fileNameLowerCase.endsWith("jpeg")
				|| fileNameLowerCase.endsWith("png")){
			return true;
		}
		return false;
		
	}

	public View makeView() {
		// TODO Auto-generated method stub
		ImageView iv = new ImageView(this);   
        //iv.setBackgroundColor(0xFF000000);   
        iv.setScaleType(ImageView.ScaleType.FIT_CENTER);   
        iv.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));   
        return iv;   
	}
	
	public class ImageAdapter extends BaseAdapter{
		
		private Context mContext;
		private int mGalleryBackground;
		private ArrayList<String> mArrayList;
		
		public ImageAdapter(Context c, ArrayList<String> list){
			mContext = c;
			mArrayList = list;
			
			//use attrs.xml to specify the Gallery's attributes
			TypedArray mTypeArray = obtainStyledAttributes(R.styleable.Gallery);
			mGalleryBackground = mTypeArray.getResourceId(R.styleable.Gallery_android_galleryItemBackground, 0);
			mTypeArray.recycle();
		}

		public int getCount() {
			// TODO Auto-generated method stub
			return mArrayList.size();
		}

		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			//new a ImageView for the image displaying
			Log.d(LOG_TAG,"getView--->and pos = " + position);
			ImageView imgView = new ImageView(mContext);
			Bitmap current = imgCache.get(position);
			if(deleteHappen || current == null){
				current = BitmapFactory.decodeFile(mArrayList.get(position));
				
				Log.e(LOG_TAG,"decodeFile path = " + mArrayList.get(position));
				
				imgCache.put(position, current);
			}
			imgView.setImageBitmap(current);	
			imgView.setScaleType(ImageView.ScaleType.FIT_XY);
			imgView.setLayoutParams(new Gallery.LayoutParams(136, 88));
			imgView.setBackgroundResource(mGalleryBackground);
			
			//deleteHappen = false;
			return imgView;
		}
		
	}

	public void onItemSelected(AdapterView<?> arg0, View arg1, int pos,
			long id) {
		// TODO Auto-generated method stub
		String imgPath = mImgPathList.get(pos);
		Log.e(LOG_TAG,"Selected Img position is " + pos + "Image Path = " + imgPath);
		Drawable drawadle = Drawable.createFromPath(imgPath);
		mImgSwitcher.setImageDrawable(drawadle); 
		
		//release Bitmap resource
		releaseBitmap();		
	}

	//just keep the bitmap in Visible range, release the rest
	private void releaseBitmap() {
		// TODO Auto-generated method stub
		int begin = mGallery.getFirstVisiblePosition();
		int end = mGallery.getLastVisiblePosition();
		
		for(int i = 0 ; i < begin ; i++){
			Bitmap delBitmap = imgCache.get(i);
			if(delBitmap != null){
				imgCache.remove(i);
				delBitmap.recycle(); 
				adapter.notifyDataSetChanged();
			}
		}
		
		for(int i = end + 1 ; i < imgCache.size() ; i++){
			Bitmap delBitmap = imgCache.get(i);
			if(delBitmap != null){
				imgCache.remove(i);
				delBitmap.recycle();
			}
		}
		
	}

	public void onNothingSelected(AdapterView<?> arg0) {
		// TODO Auto-generated method stub
		Log.e(LOG_TAG,"onNothingSelected...");
	}
	
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		// TODO Auto-generated method stub
		switch(keyCode){
			case KeyEvent.KEYCODE_BACK:
				AlertDialog.Builder builder = new AlertDialog.Builder(this);
				builder.setTitle("Are you sure want to quit!");
				builder.setCancelable(true);
		        builder.setPositiveButton("Yes", new OnClickListener(){

					public void onClick(DialogInterface dialog, int which) {
						ImageViewerActivity.this.finish();
					}
		        	
		        });
		        builder.setNegativeButton("No", null);
		        builder.show();
		}
		return super.onKeyDown(keyCode, event);
	}

	@Override
	protected void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
	}

	@Override
	protected void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
	}
}

 

        还有一些资源文件，我就不贴了，不是我偷懒，因为上个网实在是太不容易了。关于这个应用，以及一些android应用开发的体会，我后面还会发一篇文章来说说自己的想法。

         老规矩，大牛没欢迎指正我blog中的错误哈。谢谢了先....