获取SD卡根目录下图片的方法

1.获取某个目录下图片路径list

/**
     * Get pictures under directory of strPath
     * @param strPath
     * @return list
     */
    public List<String> getPictures(final String strPath) {
    	List<String> list = new ArrayList<String>();
    	
		File file = new File(strPath);
		File[] files = file.listFiles();
		
		if (files == null) {
			return null;
		}
		
		for(int i = 0; i < files.length; i++) {
			final File f = files[i];
			if(f.isFile()) {
				try{
					int idx = f.getPath().lastIndexOf(".");
					if (idx <= 0) {
						continue;
					}
					String suffix = f.getPath().substring(idx);
					if (suffix.toLowerCase().equals(".jpg") ||
						suffix.toLowerCase().equals(".jpeg") ||
						suffix.toLowerCase().equals(".bmp") ||
						suffix.toLowerCase().equals(".png") ||
						suffix.toLowerCase().equals(".gif") )
					{
						list.add(f.getPath());
					}
				} catch(Exception e) {
					e.printStackTrace();
				}
			}
		}
		
		return list;
    }

2.调用上述方法获取sd卡下的图片并显示

        List<String> list = getPictures(Environment.getExternalStorageDirectory() + "");
        if (list != null) {
        	Log.d(TAG, "list.size = " + list.size());
        	for (int i = 0; i < list.size(); i++) {
        		Bitmap bm = BitmapFactory.decodeFile(list.get(i));
        		int top = 30;
        		if (i > 0) {
        			top += BitmapFactory.decodeFile(list.get(i - 1)).getHeight() + 2;
        		}
        		canvas.drawBitmap(bm, 0, top, paint);
        	}
        } else {
        	Log.d(TAG, "list is null!!!")<br>