使用Universal-Image-Loader加载系统图片并点击放大显示

加载手机相册图片，运行效果图如下：

Universal -Image- Loader for Android的目的是为了实现异步图像加载，缓存和显示 ，支持多线程异步加载。使用用它做了一个例子，加载手机图库里的图片，点击单张图放大显示，下面是主要代码：

 public class MainActivity extends Activity {
    public static DisplayImageOptions mNormalImageOptions;
    public static final String SDCARD_PATH = Environment.getExternalStorageDirectory().toString();
    public static final String IMAGES_FOLDER = SDCARD_PATH + File.separator + "demo" + File.separator + "images" + File.separator;
    private GridView mGridView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initImageLoader(this);
        mGridView = (GridView) findViewById(R.id.multi_photo_grid);
        List datas=new ArrayList();

        datas=Util.getGalleryPhotos(this);
        mGridView.setAdapter(new ImagesInnerGridViewAdapter(datas));
    }

    private void initImageLoader(Context context) {
        int memoryCacheSize = (int) (Runtime.getRuntime().maxMemory() / 5);
        MemoryCacheAware memoryCache;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
            memoryCache = new LruMemoryCache(memoryCacheSize);
        } else {
            memoryCache = new LRULimitedMemoryCache(memoryCacheSize);
        }

        mNormalImageOptions = new DisplayImageOptions.Builder()
        .bitmapConfig(Config.RGB_565)
        .cacheInMemory(true)
        .cacheOnDisc(true)
        .resetViewBeforeLoading(true)
        .build();


        ImageLoaderConfiguration config = new ImageLoaderConfiguration
                .Builder(context)
                .defaultDisplayImageOptions(mNormalImageOptions)
                .denyCacheImageMultipleSizesInMemory()
                .discCache(new UnlimitedDiscCache(new File(IMAGES_FOLDER)))//自定义缓存路径   
                //.discCacheFileNameGenerator(new Md5FileNameGenerator())
                .memoryCache(memoryCache)
                //.memoryCacheSize(memoryCacheSize)
                .tasksProcessingOrder(QueueProcessingType.LIFO)
                .threadPriority(Thread.NORM_PRIORITY - 2)
                .threadPoolSize(3)
                .build();

        ImageLoader.getInstance().init(config);
    }

  class ImagesInnerGridViewAdapter extends BaseAdapter {
        private List datas;
        public ImagesInnerGridViewAdapter(List datas) {
            this.datas = datas;
        }

        @Override
        public int getCount() {
            return datas.size();
        }

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

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

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
           final SquareCenterImageView imageView = new SquareCenterImageView(MainActivity.this);
            imageView.setScaleType(ScaleType.CENTER_CROP);
            ImageLoader.getInstance().displayImage("file://"+datas.get(position), imageView);
            imageView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(MainActivity.this, 
                                               SpaceImageDetailActivity.class);
                    intent.putExtra("images", (ArrayList) datas);
                    intent.putExtra("position", position);

                    int[] location = new int[2];
                    imageView.getLocationOnScreen(location);
                    intent.putExtra("locationX", location[0]);
                    intent.putExtra("locationY", location[1]);

                    intent.putExtra("width", imageView.getWidth());
                    intent.putExtra("height", imageView.getHeight());
                    startActivity(intent);
                    overridePendingTransition(0, 0);
                }
            });
            return imageView;
        }

    }
}

从手机相册加载图片代码如下：

 public class Util {


    public static ArrayList getGalleryPhotos(Activity act) {
        ArrayList galleryList = new ArrayList();
        try {
            final String[] columns = { MediaStore.Images.Media.DATA,
                    MediaStore.Images.Media._ID };
            final String orderBy = MediaStore.Images.Media._ID;
            Cursor imagecursor = act.managedQuery(
                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns,null, null, orderBy);
            if (imagecursor != null && imagecursor.getCount() > 0) {
                while (imagecursor.moveToNext()) {
                       String item = new String();
                      int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
                      item = imagecursor.getString(dataColumnIndex);
                      galleryList.add(item);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        Collections.reverse(galleryList);
        return galleryList;
    }

}

下载地址：http://download.csdn.net/detail/chenhq305/9119191