android实现视频图片取缩略图

取缩略图不等同于缩放图片.

缩放图片是保持不失真的情况下缩放处理,并进行平滑处理.

缩略图则不然,允许失真,目的只是取出图片的轮廓.

保存Bitmap图片

	private  void saveBitmap(Bitmap bm,String picName) {
		Log.e(TAG, "保存图片");
		String icon_dir=mMedialist.get(mMedialist.size()-1).getIconpath().replace("/", "__");

		//		  String icon_dir=picName.replace("/", "__");
		File dir = new File(Environment.getExternalStorageDirectory().toString()+"/movdo/clip",icon_dir );
		if(!dir.exists())
			if(!dir.mkdir())
				Log.e(TAG, "don't create dir");
			else
				Log.i(TAG, "DIR is created");

		picName=picName.replace(".mp4", ".jpg");
		File f = new File(dir.getAbsolutePath(), "0.jpg");
		if (f.exists()) {
			f.delete();
		}
		try {
			FileOutputStream out = new FileOutputStream(f);
			bm.compress(Bitmap.CompressFormat.PNG, 90, out);
			out.flush();
			out.close();
			Log.i(TAG, "已经保存");
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

为图片取缩略图

	public Bitmap getImageThumbnail(String filename,Bitmap bmp,int width,int height) 
	{
		Bitmap bitmap=ThumbnailUtils.extractThumbnail(bmp, 300, 300);   
		saveBitmap(bitmap,filename);
		return bitmap;  
	}

 为视频取缩略图

	private Bitmap getVideoThumbnail(String videoPath, int width , int height){
		Bitmap bitmap = null;
		bitmap = ThumbnailUtils.createVideoThumbnail(videoPath, Thumbnails.MINI_KIND);
		bitmap = ThumbnailUtils.extractThumbnail(bitmap, width, height, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
		String filename=new String();
		saveBitmap(bitmap,mMedialist.get(mMedialist.size()-1).getItemname());
		return bitmap;
	}

 根据路径解析进Bitmap

			Bitmap thumb = BitmapFactory.decodeFile(filepath);
			getImageThumbnail(filename,thumb,300,300);